28TH ANNUAL CONDENSED MATTER AND MATERIALS MEETING WAGGA WAGGA 3 – 6 FEBRUARY 2004 CONDENSED MATTER PHYSICS, ELECTRONIC MATERIALS MATERIALS SCIENCE ENGINEERING, EARTH SCIENCES NANOSCIENCE AND NANOTECHNOLOGY, PHOTONICS NEUTRON PHYSICS, SOLID STATE THEORY, MAGNETISM SYNCHROTRON PHYSICS AND SPECTROSCOPY Australian and New Zealand Institutes of Physics 28TH ANNUAL CONDENSED MATTER AND MATERIALS MEETING Charles Sturt University, Wagga Wagga, NSW 3 February – 6 February 2004 CONFERENCE HANDBOOK ISSN-1037-1214 Organised by: Stephen Collocott, John Dunlop, Paul Gwan, Don Price, Nick Savvides CSIRO Telecommunications & Industrial Physics The Organising Committee wishes to thank Dr Gerry Haddad, Chief, CSIRO Telecommunications & Industrial Physics for his and the Division’s support, Mrs Khuen Wong for her administrative support, and Peter Saunders for the Wagga 2004 web site. CONTENTS Maps General Information Sponsors Timetable Oral Sessions Wednesday poster session Thursday poster session Abstracts Participants GENERAL INFORMATION Scientific Program All poster sessions and lectures will be held at the Convention Centre. Chairpersons and speakers must keep to the lecture program schedule. An overhead projector and microphone are available. If slides are to be used, please arrange these at least 10 minutes before the relevant session. Oversee their mounting and, preferably, test one or two prior to the session. If you intend to make a PowerPoint presentation, please check that it is compatible with the facilities provided as soon as possible. Posters must be mounted and removed at the times specified in the timetable. Administration Please wear your name tag at all times. Registration and all other administrative matters should be addressed to the registration desk or a committee member. For lost keys or if locked out of your room from 0900 to 1700, contact Ray Farnham at the Convention Centre Office for assistance; after hours, contact the Accommodation and Security Office near the corner of Valder Way and Park Way or phone them at 69332288. Convention Centre Contact Numbers Registration Desk Phone (02) 6933 4989 Convention Centre Office Phone (02) 6933 4974, Fax (02) 6933 4977 After hours Emergencies, Accommodation and Security Office Phone (02) 6933 2288 Meals, Coffee & tea, Bar Facilities All meals will be served in the dining room, except the Conference Dinner on Wednesday 4 February, which will be held in the Convention Centre. You will receive a dining room pass on registration and a ticket to the Conference Dinner. The dining room pass must be produced at every meal. It may also be required as identification for use of all other campus facilities, which are at your disposal. Morning and afternoon tea will be served each day, as indicated in the timetable. Coffee and tea-making facilities are also available in the Common Room of each building. In addition, at the time for author attendance at posters on Wednesday and Thursday, the Conference Bar will be open. The Union Bar at the rear of the Convention Centre opens in the afternoon and remains open until late in the evening. Sport and Recreational Facilities The swimming pool is open from 0730 until 2200, as are the adjacent squash courts. Tennis courts opposite the oval are also available. A wide range of facilities such as exercise bikes, weight training, table tennis and basketball are available in the gymnasium. All of the facilities are free, i.e., covered by your registration fee. SPONSORS The organisers gratefully acknowledge support from: and the following industrial and commercial sponsors: Stanton Scientific AVT Services Pty Ltd Scitek Australia Pty. Ltd. Some of these companies are exhibiting their products and we encourage you to visit them during the course of the conference. Their sponsorship has helped with the costs of running the conference and their contribution is much appreciated. We acknowledge the support of the AIP, through the local Branch Committees, in assisting students to attend the conference. TIMETABLE Tuesday 3 February 1600 onwards Registration 1600 – 1800 Conference Bar Open 1800 – 1930 Dinner 1900 onwards Posters WP may be mounted Wednesday 4 February 0730 – 0830 Breakfast 0850 – 0900 Conference Opening 0900 – 1030 Oral Session: Papers WM1 – WM4 1030 – 1100 Morning Tea 1100 – 1230 Oral Session: Papers WM5 – WM9 1230 – 1330 Lunch 1400 – 1530 Oral Session: Papers WA1 – WA6 1530 – 1600 Afternoon Tea 1545 Author attendance at Posters WP1 – WP22 (until 1645) 1600 Conference Bar opens 1645 Author attendance at Posters WP23 – WP43 (until 1745) 1800 Conference Bar closes 1900 – 2100 Conference Dinner and After Dinner Talk From Fibres to Cosmology: The Square Kilometre Array Ray Norris, ATNF 2100 Removal of WP Posters and mounting of TP Posters Thursday 5 February 0730 – 0830 Breakfast 0730 – 0900 Mounting of TP Posters 0900 – 1030 Oral Session: Papers TM1 – TM4 1030 – 1100 Morning Tea 1100 – 1230 Oral Session: Papers TM5 – TM9 1230 –1330 Lunch 1400 – 1530 Oral Session: Papers TA1 – TA6 1530 – 1600 Afternoon Tea 1545 Author attendance at Posters TP1 – TP20 (until 1645) 1600 Conference Bar opens 1645 Author attendance at Posters TP21 – TP40 (until 1745) 1800 Conference Bar closes 1800 – 1900 Dinner 2000 Trivia Quiz: Union Bar (Lindsay Davis Cup) Friday 6 February 0730 – 0830 Breakfast 0900 – 1030 Oral Session: Papers FM1 – FM5 1030 – 1100 Morning Tea 1100 – 1215 Oral Session: Papers FM6 – FM9 1215 – 1230 Prizes and Closing 1230 –1330 Lunch Wednesday Morning, 4 February 0850 – 0900 Opening: Stephen Collocott Session WM-I Chairperson: Don Price 0900 – 0930 WM1 Towards Molecular Electronics: Electron Transport through Single Molecules Karl-Heinz Müller INVITED 0930 – 1000 WM2 Coupling Molecules to Electronic Materials David Cahen INVITED 1000 – 1015 WM3 Controlled Assembly of Sb and Ag Clusters on Insulating Substrates J. G. Partridge, S. A. Brown, A. D. F. Dunbar, R. Reichel, M. Kaufmann, M. Schulze, S. Scott, C. Siegert and R. J. Blaikie 1015 – 1030 WM4 Structure of Gold Clusters (Aun, n = 3…38) Benjamin Soulé de Bas, Michael J. Ford, Michael B. Cortie Session WM-II Chairperson: Robert Robinson 1100 – 1130 WM5 Neutron scattering and material function: the example of viscous flow F. Mezei INVITED 1130 – 1145 WM6 Measuring diffuse scattering D. J. Goossens, T. R. Welberry and A. P. Heerdegen 1145 – 1200 WM7 Modulated Structures in the Ta2O5-WO3 System S. A. Schmid and A. Binder 1200 – 1215 WM8 Evidence for an orbital Peierls state in YVO3 J. Sirker and G. Khaliullin 1215 – 1230 WM9 Spin Polarised Quantum-well States in Layered Magnetic Nanostructures of Cu/Co/Cu(100) D. H. Yu and M. Donath Wednesday Afternoon, 4 February Session WA Chairperson: Tam Greaves 1400 – 1415 WA1 Development of a superconducting absolute tensor gradiometer D. L. Tilbrook, K. E. Leslie, M. Bick, C. P. Foley, R. A. Binks, J. Du, R. Gnanarajan, S. K. H. Lam, B, Thorn, P. Sullivan 1415 – 1430 WA2 Nanoscale magnetite/maghemite particle-based ferrofluids: the effect of local particle arrangement on magnetic properties H. Pardoe, W. Chua-anusorn and T. St. Pierre 1430 – 1445 WA3 The Antiferromagnetic Structure of BaPrO3 R. A. Robinson, D. J. Goossens and M. F. Telling 1445 – 1500 WA4 Theoretical Studies of a Mixed-Spin Antiferromagnetic Model for the Rare Earth Nickelates R2BaNiO5 A. M. A. von Brasch and J. Oitmaa 1500 – 1515 WA5 XRD characterisation of nanoparticle size and shape distributions N. Armstrong, W. Kalceff, J. P. Cline and J. Bonevich 1515 – 1530 WA6 The eigenvalue distribution of the time-evolution operator of a non-equilibrium system Yuichi Nakamura and Naomichi Hatano Poster Session WP Author Attendance: 1545 - 1645 WP1 – WP22 1645 - 1745 WP23 – WP43 Conference Dinner and After Dinner Talk 1900 - 2100 From Fibres to Cosmology: The Square Kilometre Array Ray Norris, ATNF Thursday Morning, 5 February Session TM-I Chairperson: Nick Savvides 0900 – 0930 TM1 Microphotonic and photonic bandgap devices: Towards all- optical technology Benjamin Eggleton INVITED 0930 – 0945 TM2 2D photonic crystal-based optical microcomponents on Indium Phosphide (InP) membrane for integrated optics C. Grillet, X. Letartre, C. Seassal, P. R. Romeo and P. Viktorovitch 0945 – 1015 TM3 Left-handed materials: recent progress and perspectives I. V. Shadrivov, A. A. Zharov, A. A. Sukhorukov and Yu. S. Kivshar INVITED 1015 – 1030 TM4 The effects of GaN capping layer thickness on electrical properties of two-dimensional electron gas in GaN/AlGaN/GaN heterostructures A. Asgari and L. Faraone Session TM-II Chairperson: Nicole Gorham 1100 – 1130 TM5 Calcite Microcrystals in the Pineal Gland of the Human Brain: Second Harmonic Generators and Possible Piezoelectric Transducers Sidney B. Lang INVITED 1130 – 1145 TM6 Magnetic Materials for Hyperthermic Cancer Treatment K. M. Spiers, J. D. Cashion, K. A. Gross and S. J. Harker 1145 – 1200 TM7 Nanoparticulate Cobalt/polymer Complexes for Biomedical Applications M. A. Zalich, T. G. St. Pierre, V. V. Baranauskas and J. S. Riffle 1200 – 1215 TM8 Computer simulation studies of the rheology of soft condensed matter P. J. Daivis, I. K. Snook, M. L. Matin, T. Kairn and M. McPhie 1215 – 1230 TM9 A Novel In-Line Micro-Fourier Rheometer Julie Glasscock and Robin Smith Thursday Afternoon, 5 February Session TA Chairperson: Kathryn Spiers 1400 – 1415 TA1 Synchrotron based Measurements of the Electronic Structure of the Organic Semiconductor Copper Phthalocyanine J. E. Downes 1415 - 1430 TA2 New approaches to fitting the Mössbauer spectra of Prussian Blue T. L. Greaves and J. D. Cashion 1430 – 1445 TA3 Light Scattering from Spin Wave Excitations in Non-Collinear Thin Film Magnetisation Structures D. C. Crew and R .L. Stamps 1445 – 1500 TA4 Experimental determination of Lévy flight distributions of the energy barriers in spin glasses N. T. Gorham, R. C. Woodward, T .G. St Pierre, R. L. Stamps, M .J. Walker, D. Greig, and J. A. D. Matthew 1500 – 1515 TA5 Inductive Measurements of Ferromagnetic Resonance R. C. Woodward, K. Kennewell, D. C. Crew and R. L. Stamps 1515 – 1530 TA6 Magnetic Properties, Curie Temperature and Microstructures of PrFeB and NdFeB-based Magnets With Additives by Blending A. Ahmad and I. R. Harris Poster Session TP Author Attendence 1545 – 1645 TP1 – TP20 1645 – 1745 TP21 – TP40 Friday Morning, 6 February Session FM-I Chairperson: Trevor Finlayson 0900 – 0930 FM1 The Fabrication of Nano-Scale Devices in Silicon F. J. Ruess, M. Y. Simmons, L. Oberbeck, K. E. J. Goh, A. R. Hamilton, T. Hallam, N. J. Curson and R. G. Clark INVITED 0930 – 0945 FM2 Fabrication of a Novel Silicon Single Electron Transistor for Si:P Quantum Computer Devices S. J. Angus, C. E. A. Smith, G. L. Snider, E. Gauja, A. S. Dzurak and R. G. Clark 0945 – 1000 FM3 The Dependence of the Critical Thickness of an InGaAs/GaAs Multilayer on Quantum Well Thickness, Barrier Thickness and Number of Periods M. Madebo, B. F. Usher and J Riley 1000 – 1015 FM4 X-ray Absorption and Emission Study of Amorphous and Nanocrystalline GaN Films Containing Buried N2 B. J. Ruck, A. Koo, F. Budde, S. Granville, A. Bittar and H. J. Trodahl 1015 – 1030 FM5 Molybdenum disulphide (MoS2) – gallium arsenide (GaAs) heterostructures for solar cell applications Ian M. Jamieson and G. Jakovidis Session FM-II Chairperson: Jan Oitmaa 1100 – 1130 FM6 Nature of the Peierls- to Mott-insulator transition in one dimension H. Fehske, G. Wellein, A. Weiße, G. Hager, A. P. Kampf, M. Sekania and A. R. Bishop INVITED 1130 – 1145 FM7 Minority-Spin Band Gap of Half-Metallic NiMnSb H. J. Trodahl, C. E. A. Grigorescu, N. Strickland and A. Bittar 1145 – 1200 FM8 Transport in Layered Materials: Polarons and Angular Magneto- Resistance U. Lundin and R. H. McKenzie 1200 – 1215 FM9 Density Functional Theory calculations of Band-gaps in Diamond Nanowires. S. P. Russo, A. S. Barnard and I. K. Snook 1215 – 1230 Closing Remarks and Prizes POSTER SESSION: Wednesday, 4 February WP1 The Effects of Multiple Scattering on the W. K. Bertram Analysis of USANS Data WP2 Crystallization in polydisperse colloidal Stephen Martin, Gary Bryant and suspensions William van Megen WP3 Studies of Magnetic Structure of T. R. Finlayson, X. Wu, T. Ersez and La1-xSrxMnO3 Colossal Magnetoresistive J. C. Schulz Perovskites WP4 Taipan - A Spectrometer for Inelastic M. E. Hagen, G. Horton, R. Moore, Neutron Scattering At The Replacement G. Braoudakis and L. D. Cussen Research Reactor WP5 High Intensity and High Resolution M. E. Hagen, B. A. Hunter and T. J. Neutron Powder Diffraction at the Noakes Replacement Research Reactor WP6 A polarised neutron study of crystal field S. J. Harker, T. J. Hicks, D. J. Goossens, transitions in CeCu6 A. M. Mulders, Y. Fei, D. Yu and S. J. Kennedy. WP7 Effects of Solutes on Membrane Phase Thomas Lenné and Gary Bryant Transitions WP8 Dynamics associated with domain walls R. L. Stamps, P. Falloon, R. Jalabert, D. Weinmann and A. Mougin WP9 Electron Transport in Disordered Films K.-H. Müller, G. Wei, J. Herrmann, of Metal Nanoparticles Linked by B. Raguse and G. Baxter Organic Molecules WP10 Finite Hydrogenated Silicon Nanotubes O. Ponomarenko, M. W. Radny and And Toroids P. V. Smith WP11 Carbon- based toroidal nanostructures O. Ponomarenko, M. W. Radny and P. V. Smith WP12 Nanocrystalline diamond grown by J. R. Rabeau, P. John and J. I. B. Wilson chemical vapour deposition using He and Ar diluted H2/CH4 gas mixtures WP13 Nucleation and Optical Properties of X. Xu, M. B. Cortie and M. Stevens Gold Nano-Hemispheres on Plate Glass WP14 Electrochemical Capacitors based on Burkhard Raguse, Wenrong Yang and Self-Assembled Gold Nanoparticle Films G. Stockton Cross-Linked with Thiols WP15 Synthesis and Characterization of RF D. M. Zhu, S. Goh, G. Jakovidis and Magnetron Sputtered Carbon L. Bourgeois Nanostructures WP16 Muon spin relaxation in spin-Peierls M. Aïn, J. Lord, J. Jegoudez and phase of NaV2O5 A. Revcolevschi WP17 Magnetic properties of Dy1-xSrxCoO3-δ D. J. Goossens, K. F. Wilson and (x = 0.67 to 0.95) M. James WP18 Magnetic Structures and Valence States D. Grimm, M. Hoffman, S. J. Campbell, of YbMn2SixGe2-x A. V. J. Edge and A. Studer WP19 Soft Magnetic Properties of N. Ito Nanocrystalline Fe89-xZr7B3Cu1Cox (x = 0 to 70) Alloys WP20 The Magnetic Properties of GdNiAl4 G. A. Stewart, W. D. Hutchison, A. V. J. Edge, K. Rupprecht, G. Wortmann, K. Nishimura and Y. Ishikawa WP21 Magnetic and Crystal Field Properties of G. A. Stewart, A. V. J. Edge, A. Studer, Thulium Calcium Manganite M. Elcombe, J. Horvat and R. Lewis WP22 Structural and Magnetic Properties of J. L. Wang, S. J. Campbell, S. James, DyFe12-xNbx Compounds A. V. J. Edge and D. Grimm WP23 Exchange bias in a model system R. L. Stamps, W. Pang and Z. Celinski WP24 Analysis of an Ideal Amorphous Solid L. Th. To and Z. H. Stachurski WP25 A Comparison of the Influence of M. Jones, M. M. Suder, A. Amiet, A. V. J. Different Dopants on the Radar- Edge, G. A. Stewart, W. D. Hutchinson absorbing Properties of Barium and P. Jewsbury Hexaferrite WP26 Analysis of hydrogenated amorphous M. Rybachuk and J. M. Bell carbon films deposited using an open plasma generator under various bias voltage WP27 The Electric Field Gradient of FePS3 : a A. E. Smith, K.C. Rule, J.D. Cashion and comparison between calculated and T.J. Hicks measured values WP28 Mapping Disorder-Order Induced A. Tadich, L. Broekman, J. Riley, Changes To The Fermi Surface Of R. Leckey, T.Seyller, K.Emtsev and Cu3Au Using A New Toroidal Electron L. Ley Energy Analyser WP29 High Resolution Angle Resolving A. Tadich, L. Broekman, E. Huwald, Toroidal Electron Spectrometer R. Leckey, J. Riley, T. Seyller and L. Ley WP30 Whiskies: further EPR and Antioxidant Irwin Cheah, Steven J. Langford, Jim Efficiency Studies Kelly and Gordon Troup WP31 An EPR and Antioxidant Efficiency Irwin Cheah, Steven J. Langford and Study of the Two Pinebark Phenolic Gordon Troup Extracts Pycnogenol (R) and Endogenol WP32 Bilirubin photoisomer variable quantum G. Agati, Marina Mazzoni, R. Pratesi yield – end of a chapter and Gordon Troup WP33 High-Power Ultrasonic Treatment of A. F. Collings, P. B. Gwan and A. P. Contaminated Soils and Sediments Sosa Pintos WP34 Phase Transformations in the J. E. Daniels, M. M. Elcombe, T. R. Ca1-xSrxTiO3 Perovskite System Finlayson and E. R. Vance WP35 High-temperature viscoelastic relaxation: Ian Jackson and Ulrich Faul in search of the creep function WP36 Proximity effect in low resistivity yttria- S. K. H. Lam and S. Gnanarajan stabilized-zirconia thin films WP37 A new thin film deposition process by Thierry Paulmier, Emad Kiriakos, John cathodic plasma electrolysis Bell and Peter Fredericks WP38 The Storage of Nuclear Waste in T. M. Sabine Concrete WP39 Fermi Surface Comparisons For A. E. Smith, T.R. Finlayson, Robert Materials Susceptible To Phase Leckey and J. Riley Transitions WP40 Formation of Ion Tracks in Single- A. S. Khalil, A. M. Stewart, M. C. Crystal Indium Phosphide Irradiated by Ridgway, L. T. Chadderton, D. J. Swift Heavy Ions Llewellyn and A. P. Byrne WP41 Fe and Mg solubility in the Ca site of E. R. Vance, J G. Cashion, J .V. Hanna, zirconolite, CaZrTi2O7 Z. Garrett and M. Bhati WP42 Thermal Expansion Studies of Ni2MnGa X. D. Wu and T. R. Finlayson Shape-Memory Material WP43 Characterization of microstructural X. Y. Xiong, P. Tran, S. P. Ringer and evolution in Fe-C(-Mn) alloys during E. Pereloma early stages of ageing using atom probe POSTER SESSION: Thursday, 5 February TP1 Surface Electron Structure of Short- I. Bartos, T. Strasser, W. Schattke Period Semiconductor Superlattice TP2 Quantum pumping and geometric phases Huan-Qiang Zhou, Sam Young Cho, in nanoscale electronic devices Urban Lundin, and Ross H. McKenzie TP3 High Resolution Lithography of PMMA A. Cimmino, D. Gassull, S. Prawer, with a Scanning Probe Microscope D. Jamieson TP4 Towards a Quantum-Limited Charge N. A. Court, D. J. Reilly, T. M. Detector Buehler, R. P. Starrett, R. G. Clark and A. R. Hamilton TP5 Influence of N2 Background Pressure on T. Dieing and B. F. Usher the Incorporation of Arsenic during MBE Growth of GaAs TP6 Comparison of hydrogen resist removal T. Hallam, L. Oberbeck, F. J. Ruess, techniques for STM-fabricated nanoscale N. J. Curson, M. Y. Simmons and devices R. G. Clark TP7 Measurement and Simulation of the S. M. Hearne, M. D. H. Lay and effects of ion induced defects on ion D. N. Jamieson beam induced charge (IBIC) measurements in Si Schottky diodes TP8 Magnetic Resonance and P:Si Qubits W. D. Hutchison, D. Tempelaars, R. Bramley, A. R. Hamilton, E. Gauja and R .G. Clark TP9 Electron transport in multi-layer S. P. Lee, B. C. C. Lough, X. Z. thermionic cooling structures Shang, Q. Wang, R. A. Lewis and C. Zhang TP10 Characterization of Si-SiO2 Trap Density D. R. McCamey, M. J. Francis, J. C. Due to Ion Implantation McCallum, A. R. Hamilton, A. D. Greentree and R .G. Clark TP11 Nanofabrication of Charge-based Si:P M. Mitic, T. M. Buehler, A. J. Quantum Computer Devices using Ferguson, V. Chan, E. Gauja, F. E. Single-ion Implantation Stanley, S. J. Angus, K. H. Lee, A. D. Greentree, D. J. Reilly, A. R. Hamilton, A. S. Dzurak, R. G. Clark, C. I. Pakes, C. Yang, D. N. Jamieson and S. Prawer TP12 The diffusion mechanism of Mn in GaAs. D. James, J. Riley, R. Leckey, Yvegen Biltosky and Kathryn Prince TP13 Atomic structure of the hydrogen Th. Seyller, N. Sieber, A. Taddich, saturated a-planes of 4H-SiC D. James, J. D. Riley, R. G. C. Leckey and L. Ley TP14 Spin structure of small quantum dots C. Sloggett and O. P. Sushkov TP15 Local bonding environment of low M. T. K. Soh, N. Savvides, C. A. temperature silicon nitride thin films Musca and L. Faraone produced by plasma-enhanced chemical vapour deposition TP16 Variations in the Apparent Optical Band- K. S. A. Butchera, M. Wintrebert- gap of RPE-CVD Grown Indium Nitride Fouqueta, P. P.-T. Chena, T. L. Thin Films Tansleya and K. E. Princeb TP17 TP18 TP19 Electronic Structure of Single Crystal C. Bowles, C. Chen, A. Kheifets, Copper Measured by Electron M. Vos and E. Weigold Momentum Spectroscopy TP20 Fast Simulation of a Quantum Phase J. P. Barjaktarevic, G. Milburn and Transition in an Ion-Trap Realisable R. H. McKenzie Unitary Map TP21 Magnetic Materials for Hyperthermic K. M. Spiers, J. D. Cashion, Cancer Treatment K. A. Gross and S. J. Harker TP22 Mixed-Spin S=(½,1) Quantum Weihong Zheng and J. Oitmaa Ferrimagnet at Zero Temperature TP23 Phase Diagram of the BCC S=½ J. Oitmaa and Weihong Zheng Heisenberg Antiferromagnet with First and Second Neighbour Exchange TP24 Comparative numerical study of G. Schubert, A. Weisse and localization in disordered electron H. Fehske systems TP25 Structure factors for the alternating C. J. Hamer, Weihong Zheng and Heisenberg chain R. R. P. Singh TP26 Superconducting Correlations and Model Y. Hancock and D. M. Paganin System Design TP27 Low-lying excitations in odd-legged A. Lüscher, R. Noack, G. Misguich, spin-½ tubes with strong rung coupling V. Kotov and F. Mila TP28 Photoconductivity in Disordered GaN A. Koo, B. J. Ruck, H. J. Trodahl, F. Budde and A. Bittar TP29 TP30 Quantum Interference with Heisenberg D. J. Miller Spin Chains TP31 Schockley and Rydberg Surface States M. N. Read and Quantum Wells on the Cu(111) Surface TP32 Searches for the electron electric dipole T. N. Mukhamedjanov, O. P Sushkov, moment and nuclear anapole moments in J. M Cadogan and V. A. Dzuba solids TP33 Apparent Sizes of Solute Atoms and A. E. Smith and S. Homolya Vacancies in Aluminium from First Principles TP34 Superconducting Spiral Phases in the Oleg P. Sushkov and Valeri N. Kotov two-dimensional t-J model TP35 Corrosion Resistance of Organic Layers J. D. Smith, T. R. Finlayson, on GaAs via X-ray Reflectometry C. Kirchner and U. Klemradt Characterization TP36 New tools for the numerical calculation Alexander Weisse of dynamical correlation functions at finite temperature TP37 Does the probability density imply the Rotha P. Yu, David M. Paganin and equation of motion? Michael J. Morgan TP38 Reactive Ion Etching of Microphotonic J. Du, J. Glasscock, J. Vanajek and Structures N. Savvides TP39 An Apparent Shift in Optical Constants A. I. Maaroof and G. B. Smith in Nanostructured Metal Films Overcoated with Insulator: a New class of Multilayer Thin Film Systems TP40 Silicon Microphotonic Waveguides V. Ta’eed, M. J. Steel, C. Grillet, B. Eggleton, J. Du, J. Glasscock and N. Savvides Oral Sessions Abstracts Wednesday 4 February WM1 Towards Molecular Electronics: Electron Transport through Single Molecules Karl-Heinz Müller CSIRO Telecommunications and Industrial Physics, Sydney 2070, Australia. Molecular electronics, a new emerging science area in the field of nanotechnology, is seen as a potential replacement for silicon device-technology in the next decade. To enable such a technology, an essential initial requirement is a detailed understanding of the electrical conduction properties of molecules placed between metal electrodes. We recently investigated the electrical conduction of single molecules using first-principle quantum mechanical calculations based on the density functional theory and non-equilibrium Green’s function techniques. We demonstrate that each molecule has its own distinct current-voltage characteristic, determined by the positions of the molecular energy levels and the degree of electrode-molecule coupling. We show that the calculated attenuation factors of molecular wires made of polyenedithiol, polyphenyldithiol and alkanedithiol agree with experimental data. Furthermore we reveal that photoisomerization of azobenzene can be utilized as an electrical molecular switch and that bipyridinedithiol, in the presence of a gate electrode, can function as a single-molecule field-effect transistor. Different experimental techniques that help to elucidate the conduction properties of single molecules will be discussed. WM2 Coupling Molecules to Electronic Materials D. Cahen Department of Materials & Interfaces, Weizmann Institute of Science, Israel If we would know how to place molecules at metal-semiconductor interfaces, even if only as poorly organized, partial, rather than ideal monolayers, this could give a significant degree of electronic control over these interfaces and, thus, over the simplest of electronic devices.1 This is primarily because electron energetics at interfaces determine the electronic behaviour of semiconductor & metal contacts.2 Two types of control are distinguished, electro-static and -dynamic. For the former, requirements for (near-)ideally structured monolayers can be relaxed because the molecules can act as "gatekeepers”, leading to devices with no current flow through molecules.1 In systems with near-ideal molecular films, electronic transport through molecules is often by "through bond" tunneling.3 To make device structures reproducibly, soft contacting methods are needed.3 Results obtained with such methods show how intimate contact between molecules and metal can polarize the contacts.1,4 Experimental evidence is accumulating that in most devices with molecules, the nature of the molecule/electrode contact is crucial for the resulting junction.3,5 1. A.Vilan et al. Nature 404 (2000) 166; J. Phys. Chem B, 107 (2003) 6360; G. Ashkenasy et al. Acc. Chem. Res. 35 (2002) 121 2. D. Cahen, A. Kahn, Adv. Mater., 14 (2003) 271 3. Y. Selzer et al., J. Phys. Chem. B 106 (2002) 10432; D. Cahen, G. Hodes, Adv. Mater. 14 (2002) 789; A. Salomon, D. Cahen, S. Lindsay, C. Frisbie et al, Adv. Mater., 15 (2003) 1881. 4. A. Vilan, D. Cahen, Adv. Funct. Mater. 12 (2002) 795; H. Haick et al., to be published 5. Y. Selzer et al., Angew. Chem. Int. Ed., 41 (2002) 827. WM3 Controlled Assembly of Sb and Ag Clusters on Insulating Substrates J.G. Partridgea,b, S.A. Browna,b, A.D.F. Dunbara,b, R. Reichela,b, M. Kaufmanna,b, M. Schulzea,b, S. Scotta,b, C. Siegerta,b and R. J. Blaikiea,c a Nanostructure Engineering Science and Technology (NEST) Group and the MacDiarmid Institute of Advanced Materials and Nanotechnology b Department of Physics and Astronomy, University of Canterbury, New Zealand c Department of Electrical and Computer Engineering , University of Canterbury, New Zealand Atomic clusters exhibit a range of useful electronic, chemical and magnetic properties, and show great potential as building blocks for nanoscale electronic and photonic devices. To date, self-assembly of cluster structures has relied on surface diffusion of clusters, or of atoms which aggregate to form clusters. Chains resembling wires can be achieved through diffusion to the naturally occurring step-edges on graphite, but since the position of these surface defects is random, the placement of the wires cannot be controlled. Electrical characterization is impossible unless the wires are transplanted onto an insulating surface and contacts are introduced. The cluster assembly methods reported here occur on passivated silicon substrates. In the first method, clusters are deposited over interdigitated conducting fingers with separations equal to >10 cluster diameters. A percolating conduction path forms at a critical coverage value and the deposition can be stopped at this value. In the second method, V-grooves are employed as template elements; the momentum of the deposited clusters causes them to bounce or slide to the apex of the V-groove, where they assemble into a wire. Since diffusion is not an important factor, the assembly process is insensitive to defects and preformed lithographically defined electrical contacts ensure that the wire is self-contacting and that onset of conduction can be observed. Control of the flow rate of argon gas into the inert gas aggregation source allows control over the cluster velocity and hence the morphology and width of the wires formed. Wires have been fabricated with widths down to ~100nm and lengths exceeding 150µm. WM4 Structure of Gold Clusters (Aun, n = 3…38) Benjamin Soulé de Bas, Michael J. Ford, Michael B. Cortie Institute for Nanoscale Technology University of Technology, Sydney, PO Box 123, Broadway, NSW 2007, Australia We have investigated small gold clusters using Density Functional Theory (DFT) as implemented in the SIESTA package [1]. Simulated Annealing (SA) with a Lennard-Jones (LJ) pair potential and a Gupta n-body potential was used as a first stage geometry optimisation to locate the global minima. Low energy candidates from the SA were then used as starting points for the full ab initio structure optimisation. We have already reported geometries for clusters of 3 to 20 atoms [2]. DFT calculations predicted disordered structures for Aun with n > 9, and a transition from planar to 3-dimensional structures between Au6 to Au7. The LJ potential predicted high symmetry structures up to 20 atoms. Here we extend this work to the clusters Au21 to Au38. The LJ potential favours ordered structures, whereas the Gupta potential predicts equally ordered and disordered structures. For the magic cluster Au38, one of the low energy structures predicted by the Gupta potential is the truncated octahedron. Disordered structures are predicted by DFT for Au21 to Au38. For each of these clusters DFT also predicts a number of disordered structures lying close in energy. This was also the case for clusters in the size range 3 to 20 atoms. It is reasonable to conclude from these results that experimentally prepared gold clusters will contain a distribution of structures even if the clusters are monodisperse in size. We are now in the process of pushing these calculations towards larger sizes and are performing ab initio calculations for clusters in the range of 400 atoms. Such calculations are approaching clusters sizes that are experimentally more relevant. [1] J M Soler, E Artacho, J D Gale, A Garcia, J Junquera, P Ordejon, and D Sanchez-Portal, J. Phys.: Condens. Matter 14, 2745 (2002). [2] B Soulé de Bas, M J Ford, M B Cortie, Gold 2003 New Industrial Applications for Gold, Sept 2003, Vancouver, Canada. WM5 Neutron Scattering and Material Function: the Example of Viscous Flow F. Mezei Hahn-Meitner-Institut, Berlin and Los Alamos National Laboratory, Los Alamos Neutron scattering is the one direct probe at our disposal to explore materials in space and time on the atomic scale. Indeed, in crystalline matter it proved itself to be an extremely effective tool to provide detailed information atom by atom on the microscopic structure and motion – at least when sizable single crystals can be made. Many materials of primary interest in nature, however, are not available in the form of large single crystals or they are not even crystalline. Neutron scattering has been used with great success to study non-crystalline matter too, nevertheless in more complex substances we are far from an atom-by-atom exploration of structure and dynamics. Increasing sensitivity to be provided by advanced neutron sources and instruments combined with more powerful model calculations will offer unprecedented opportunities in this field. As a rather modest illustration the case of the exploration of supercooled liquids near the glass transition will be discussed in more detail. In such systems an unexpected dynamic process has been discovered more than a decade ago, whose nature remained a subject of guesswork for a long time. More recent evidence suggests that the flow in highly viscous media is a dynamically heterogeneous process, combining a fast and a slow component on nanoscopic length scale. WM6 Measuring Diffuse Scattering D.J. Goossens, T.R. Welberry and A.P. Heerdegen Research School of Chemistry, Australian National University, Canberra Australia. Diffuse scattering – electron, neutron, X-ray -- is a valuable probe of the short range order in a crystal [1]. Because typical diffuse scattering intensities are ~103 – 104 orders of magnitude smaller than those of Bragg peaks, in order to record diffuse scattering over substantial regions of reciprocal space, multidetectors, low noise and if possible a bright source are all desirable. Even then, the need to measure the weak diffuse in the presence of the Bragg peaks, to reduce air scattering and other sources of noise and to perform the experiments in a reasonable length of time makes the data collection demanding. Methods for the collection of diffuse scattering in the laboratory, at a synchrotron and using time-of-flight Laue neutron diffraction (at ISIS) are outlined, including the scattering geometries used. The advantages and disadvantages of these various techniques are discussed and the types of data which can be collected are illustrated using a single family of samples – benzil (C14H10O2) and its derivatives [2]. We conclude that the ability to collect diffuse scattering data is improving all the time, but that a strong interaction between the user and the instrumentation is needed to get the best results. 1. T.R. Welberry and B.D. Butler, Chem. Rev. 95 2369-2403 (1995) 2. T.R. Welberry, D.J. Goossens, A.J.Edwards and W.I.F. David, Acta Crystallographica A. A57 101-109 (2001). WM7 Modulated Structures in the Ta2O5-WO3 System S. A. Schmida and A. Binderb a School of Chemistry, The University of Sydney, NSW 2006, Australia. b Institute for Inorganic Chemistry, University of Tübingen, Germany. Systems that form modulated structures are a fascinating class of materials, which lack lattice periodicity but may still be perfectly long-range ordered. Such systems exist across the whole range of chemical disciplines from organic conductors to high-Tc superconductors and minerals. Consequently the importance of modulated structures has been recognised, but there have been few systematic studies across composition ranges of solid solutions that form modulated structures. Such a systematic investigation is expected to further our understanding of crystal chemical and structural aspects of modulated structures as well as the reasons for their existence. One example for a modulated structure, the wide-range, non-stoichiometric solid solution (1-x)Ta2O5•xWO3, 0 ≤ x ≤ 0.267, has been subject to intensive investigation over many years [2]. Owing to the phase transition at 1360°C, large single-crystals of L-Ta2O5 were impossible to grow. Thus, attempts were made to stabilise the phase by the addition of other oxides. For WO3, a series of anion-deficient α-UO3-related 'line phases' with basic structure dimensions very similar to those of L-Ta2O5 was found within the composition range (1-x)Ta2O5•xWO3, 0 ≤ x ≤ 0.267. X-ray and neutron powder diffraction data for a number of compositions were collected at the ANBF and at Lucas Heights, respectively. The results of the structure refinements using JANA [3] will be presented. 1. Withers, R. L., Schmid, S. & Thompson, J. G. (1998). Prog. Solid State Chem. 26, 1. 2. Schmid, S., Fütterer, K. & Thompson, J. G. (1996). Acta Cryst. B52, 223. 3. Petrícek, V. & Dušek, M. (2000). JANA2000, Programs for Modulated and Composite Crystals, Institute of Physics, Praha, Czech Republic. WM8 Evidence for an Orbital Peierls State in YVO3 J. Sirkera, G. Khaliullinb a UNSW, School of Physics, Sydney 2052, Australia. b Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany. Neutron spectroscopy has revealed a highly unusual magnetic structure and dynamics in YVO3, an insulating pseudocubic perovskite that undergoes a series of temperature induced phase transitions between states with different spin and orbital ordering patterns. A good description of the neutron data is obtained by a theoretical analysis of the spin and orbital correlations of a quasi-one-dimensional model with spins S=1. At small Hund's coupling JH we discover dimerization in a pure electronic system solely due to a dynamical spin-orbital coupling. Above a critical value JH, a uniform ferromagnetic state is stabilized at zero temperature. More surprisingly, we observe a temperature driven dimerization of the ferrochain, which occurs due to a large entropy released by dimer states. This leads to the tentative identification of one of the phases of YVO3 with the “orbital Peierls state'', a theoretically proposed many-body state comprised of orbital singlet bonds. [1] J. Sirker and G. Khaliullin, J. Phys. B 67, 100408(R) (2003). [2] C. Ulrich, G. Khaliullin, J. Sirker, M. Reehuis, M.~Ohl, S. Miyasaka, Y.Tokura, and B. Keimer, Phys. Rev. Lett. (in print, 2003) WM9 Spin Polarised Quantum-Well States in Layered Magnetic Nanostructures of Cu/Co/Cu(100) D. H. Yua and M. Donathb a Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia. b Physics Institute, University of Muenster, D-48149, Muenster, Germany. The unoccupied electronic structures of bilayer Co/Cu(100) and trilayer Cu/Co/Cu(100) structures have been investigated by spin-resolved inverse photoemission. For the first time, the spin-polarised unoccupied quantum-well states have been observed for both systems. The exchange splitting of the quantum-well states and the bulk-like sp band of Co (100) have been determined. A simple phase accumulation model simulated the electron confinement in the ultra-thin Co(100) film very well. The offset between the Co and Cu X4’ point provides the confinement potential for electrons in the Co film. For the sandwich structure of Cu/Co/Cu(100), in addition to the spin-polarised quantum-well states, surface states and a surface resonant state at the copper/vacuum interface, and bulk-like minority d contributions from the underlying ferromagnetic Co layer have also been identified. The quantum-well states are shown to develop into a surface resonant state as a function of the electron momentum, as evidenced by the loss of the exchange splitting. The quantum-well states in Cu/Co structure are formed by resonance due to high reflectivity, because there is no absolute confinement potential for this structure. The experiment has shown that the spin resolution provides a possible access to the penetration depth of the wave function of the surface state and surface resonant state. Acknowledgments: D H Yu would like to acknowledge the hospitality of the University of Muenster and support by the Alexander von Humboldt foundation in Germany. WA1 Development of a Superconducting Absolute Tensor Gradiometer D.L. Tilbrook, K.E. Leslie, M. Bick, C.P. Foley, R.A. Binks, J. Du, R. Gnanarajan, S. K. H. Lam, B. Thorn, P. Sullivan. CSIRO Telecommunications and Industrial Physics, PO Box 218, Lindfield, NSW, 2070, Australia. Although the use of high-temperature superconducting (HTSC) materials for the fabrication of SQUID-based magnetometers and gradiometers is now well established [1] these materials remain more difficult to use than the alternative low-temperature superconducting materials. In particular, the lack of HTSC wires and the difficulty of forming superconducting connections means that the standard low-Tc design practice of forming gradiometer coils from superconducting wires, is not applicable in high-Tc materials. Designs for HTSC axial gradiometers [2] have been implemented only by means of electronic or software subtraction of the outputs of a pair of SQUID magnetometers, and generally have insufficient dynamic range to be rotated in the earth’s magnetic field. In this work we describe the development of a new concept axial gradiometer [3] which is implemented through the use of a flux transformer pick-up loop structure patterned on flexible superconducting tape that is inductively coupled to a SQUID-based magnetometer. This is the first example of a series axial gradiometer in HTSC materials and offers significant advantages over the two-SQUID systems mentioned above. The design provides sufficient dynamic range and intrinsic noise immunity to operate while rotated in the full earth’s field. Data analysis facilitates the measurement of the absolute value of all five independent components of the magnetic gradient tensor using a set of three such gradiometers, each of which is rotated about its axis. Initial results are presented showing the measurement by a prototype instrument of the tensor gradient of a small bar magnet. 1. For example, W. Eidelloth et. al., Appl. Phys. Lett., 59, 3473 (1991); S. Knappe et. al., Cryogenics 32, 881, (1992); M. N. Keene et. al., Appl. Phys. Lett. 64, 366 (1994); G. M. Daalmans, Appl. Supercond., 3, 399, (1995); M. I. Faley, et. al., IEEE Trans. Appl. Supercond., 7, 3702 (1997). 2. For example, R. H. Koch et. al., Appl. Phys. Lett., 63, 403, (1993); H. J. M. ter Brake et. al., IEEE Trans. Appl. Supercond., 7, 2545, (1997); J. Borgmann et. al., Rev. Sci. Instrum., 68, 2730, (1997). 3. D.L. Tilbrook, “The design of a new concept HTSC axial gradiometer”, Submitted to Physica C. WA2 Nanoscale Magnetite/Maghemite Particle-based Ferrofluids: the Effect of Local Particle Arrangement on Magnetic Properties H. Pardoe, W. Chua-anusorn and T. St. Pierre School of Physics, The University Of Western Australia, Nedlands W.A. 6009, Australia. Many biological systems possess the ability to synthesise ferrimagnetic iron oxide particles as magnetite (Fe3O4). These biogenic magnetite particles have individual particle sizes of less than 100 nm, a range that limits them to single magnetic domains. The development of aqueous based ferrofluids containing ferrimagnetic particles within this size range has provided a model that can be used to study the properties of such systems. There are also a number of new biomedical and diagnostic applications that utilise ferrofluids and whose effectiveness depends on the magnetic properties of the ferrofluid. Nanoscale magnetite/maghemite-based ferrofluids were chemically synthesised by coprecipitation of Fe(III) and Fe(II) in alkaline conditions in the presence of dextran or polyvinyl alcohol. Characterisation by magnetometry, Mössbauer spectroscopy and electron microscopy and diffraction indicate that the presence of the dextran and polyvinyl alcohol affects both the particle size and the local distribution of the ferrimagnetic particles with respect to one another. We show that the arrangement of these particles, as determined by the presence of dextran or polyvinyl alcohol, plays a major role in determining the magnetic properties of the ferrofluid. The fact that the presence of dextran or polyvinyl alcohol during magnetite synthesis exerts some control over the arrangement of the particles may prove useful for applications in which specific magnetic properties are desirable, both when modelling biological systems, and utilising the magnetic properties of ferrofluids for biomedical applications. WA3 The Antiferromagnetic Structure of BaPrO3 R. A. Robinsona, D. J. Goossensa,b and M. F. Tellingc a Bragg Institute, ANSTO, PMB-1, Menai, NSW 2234 b Research School of Chemistry, ANU, Canberra, ACT 0200. c ISIS, Rutherford Appleton Laboratory, Chilton, Oxon. OX11 0QX, UK In this study, we report the magnetic space group and moment direction in the canted antiferromagnetic system BaPrO3. While previous work had shown that perovskite-based BaPrO3, which is orthorhombic crystallographically, orders antiferromagnetically below 11.7K, and that it also exhibits weak ferromagnetism at the same temperatures, the exact magnetic symmetry and moment directions were previously undetermined. In this report, we show, by means of cold-neutron high-resolution powder diffraction, that the magnetic (Shubnikov) group is in fact Pb’n’m, and that the antiferromagnetism lies along the a-axis, with µx = 0.37±0.03 µB. This is qualitatively and quantitatively consistent with previous neutron diffraction results reporting the configurational symmetry of the antiferromagnetism. Our model explicitly allows for ferromagnetism, and necessarily implies that the ferromagnetism previously observed in bulk magnetisation measurements must lie along the z-axis. We discuss ways in which this prediction might be tested, even in the absence of single crystals of BaPrO3. WA4 Theoretical Studies of a Mixed-Spin Antiferromagnetic Model for the Rare Earth Nickelates R2BaNiO5 A.M.A. von Brasch and J. Oitmaa School of Physics, University of New South Wales, Sydney 2052, Australia. An interesting class of magnetic materials was recently discovered, the rare earth nickelates R2BaNiO5, where R is a rare earth ion [1]. When the rare earth species is non-magnetic, the system is a very good experimental realisation of a Haldane-gap S = 1 antiferromagnet [2], with a gap in the excitation spectrum and the absence of long-range order [3]. If the rare earth ions are magnetic, long-range antiferromagnetic order is observed, with the associated gapless order parameter excitations. However, the Haldane excitations are also seen to co-exist in these compounds, even in the ordered phase. It has been proposed that the magnetic behaviour of these compounds could be modeled with two dimensional layers, consisting of alternating rows of S = 1 and S = ½ spins, interacting antiferromagetically [4]. We will present our preliminary studies of such a mixed-spin antiferromagnetic model, performed using cluster series expansion techniques and analytical spin-wave theory. 1. Zheludev, J.M. Tranquada, T. Vogt and D.J. Buttrey, Phys. Rev. B 54, 6437 (1996). 2. J. Darriet and L.P. Regnault, Solid State Commun. 86, 409 (1993). 3. F.D.M. Haldane, Phys. Rev. Lett. 50, 1153 (1983). 4. Y. Takushima, A. Koga, and N. Kawakami, Phys. Rev. B 61, 15189 (2000). WA5 XRD Characterisation of Nanoparticle Size and Shape Distributions N. Armstronga, W. Kalceffa, J. P. Clineb & J. Bonevichc a Department of Applied Physics, University of Technology Sydney, NSW 2007, Australia b Ceramics & c Metallurgy Divisions, National Institute of Standards and Technology, Gaithersburg, MD 20899-8523, USA The form of XRD lines and the extent of their broadening provide useful structural information about the shape, size distribution, and modal characteristics of the nanoparticles comprising the specimen. Also, the defect content of the nanoparticles can be determined, including the type, dislocation density, and stacking faults/twinning. This information is convoluted together and can be grouped into “size’’ and “defect’’ broadening contributions. Modern X-ray diffraction analysis techniques have concentrated on quantifying the broadening arising from the size and defect contributions, while accounting for overlapping of profiles, instrumental broadening, background scattering and noise components [1-4]. We report on a combined Bayesian/Maximum Entropy (MaxEnt) technique developed for use in the certification of a NIST Standard Reference Material (SRM) for size-broadened line profiles [1]. The approach used was chosen because of its generality in removing instrumental broadening from the observed line profiles, and its ability to determine not only the average crystallite size, but also the distribution of sizes and the average shape of crystallites. Moverover, this Bayesian/MaxEnt technique is fully quantitative, in that it also determines uncertainties in the crystallite-size distribution and other parameters. Both experimental and numerical simulations of size broadened line-profiles modelled on a range of specimens with spherical and non-spherical morphologies are presented to demonstrate how this information can be retrieved from the line profile data. The sensitivity of the Bayesian/MaxEnt method to determining the size distribution using varying a priori information are emphasised and discussed. [1] N. Armstrong, W. Kalceff, J. P. Cline & J. Bonevich, J. NIST Res., 108, (2003) In press [2] J. I. Langford, D. Louër & P. Scardi, J. Appl. Cyst., 33, 964-974, (2000). [3] P. Scardi, M Leoni & Y. H. Dong, Eur. Phys. J. B, 18, 23-30 (2000). [4] P. Scardi & M Leoni, Acta Cryst., A58, 190-200, (2002). WA6 The Eigenvalue Distribution of the Time-Evolution Operator of a Non-Equilibrium System Yuichi Nakamura a and Naomichi Hatano b a Department of Physics, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan b Institute of Industrial Science, University of Tokyo, Tokyo, Japan We study a one-dimensional cellular automaton as a discrete traffic-flow model. We investigate the eigenvalue distribution of the time-evolution operator of the model. We show that the eigenvalue distribution can indicate stationary flows in the non-equilibrium system with interaction. We incorporate the flux operator into the time-evolution operator; we generalize the matrix elements of the flow of a specific car from unity to e g [1]. Figure 1 shows the eigenvalue distribution for ten sites. All the eigenvalues are on the unit circle for g = 0. By increasing g , we notice in Fig.1 a remarkable difference between the free phase (the number of the cars is from one to five) and the congested phase (the number of the cars is from six to nine). We can thus regard the congested phase as a localized state and the free phase as an extended state. In the present study, we used a recently introduced algorithm of computing the eigenvalue distribution of huge non-Hermite matrices [2]. 2 car=1 (free) Fig.1: The eigenvalue 1.5 car=2 (free) distribution for g =0.5 (ten sites). car=3 (free) In the free phase, the 1 car=4 (free) eigenvalues do not depend on car=5 (free)0.5 car=6 (congested) the number of the cars and are car=7 (congested) located on the circle of radius 0 car=8 (congested) e g. In the congested phase, the -0.5 car=9 (congested) eigenvalues are located closer to the unit circle. Note that zero -1 eigenvalues exist when the -1.5 number of the cars is from two to eight. -2 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 Real Part [1] N. Hatano and D. R. Nelson, Phys. Rev. Lett. 77, 570 (1996); Phys. Rev. B 56, 8651 (1997) [2] N. Hatano and J. Yamasaki, in preparation. Imaginary Part Oral Sessions Abstracts Thursday 5 February TM1 Microphotonic and Photonic Bandgap Devices: Towards All-Optical Technology Benjamin J. Eggleton ARC Centre of Excellence for Ultra-high-bandwidth Devices for Optical Systems (CUDOS) School of Physics, University of Sydney. NSW 2006 The Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS) was created under the Australian Research Council’s Centres of Excellence program. Of the eight centres that were funded, three (including CUDOS) are heavily based around leading-edge research in optics. CUDOS’ research is aimed at the study and potential applications of linear and nonlinear optical behavior in micro-structured materials. Examples of such materials include photonic crystals and micro-structured optical fibres. The CUDOS team aims to investigate phenomena driven by high intensity optical fields propagating through these materials. This presentation will overview the CUDOS research program with particular emphasis on microstructured materials and novel microfabrication techniques. TM2 2D Photonic Crystal-based Optical Microcomponents on Indium Phosphide (InP) Membrane for Integrated Optics C. Grilleta, X. Letartreb, C. Seassalb, P. R. Romeob and P. Viktorovitchb a Centre for Ultra-high-bandwidth Devices for Optical Systems School of Physics, University of Sydney. b Laboratoire Electronique Optoelectronique Microsystemes Ecole Centrale de Lyon, France Realization of optical devices containing photonic crystals [1] seems a very promising way to fulfill the requirements of miniaturization of integrated optics [2]. Photonic Crystals (PC) are periodic dielectric structures conceived so as to modify the behavior of the photons in the same way that a semi conductor crystalline affects electrons properties. They thus provide an effective control of light on a wavelength scale. Moreover insertion of defects in the periodic lattice allows the realization of microcavities which can be exploited either to reinforce the interaction matter-radiation (light emission and detection), or to filter and redirect the light on very short distances. We first describe concepts and general characteristics related to two-dimensional (2D) planar (finite height) photonic crystal and their fabrication. Then, we focus on 2D PC waveguides realized on InP membrane. Original experimental studies [3], carried out by a diffracted photoluminescence technique, allow us to release, as well the modal properties of the guide, as the access to the propagation losses. 1. E. Yablonovitch, Phys. Rev. Lett. 58, 2059 (1987). 2. R. D. Meade, A. Devenyi, J. D. Joannopoulos, O. L. Alerhand, D. A. Smith, and K. Kash, J. Appl. Phys. 75, 4753 (1994). 3. X. Letartre, C. Grillet, P. R. Romeo, C. Seassal, P. Viktorovitch, M. Le Vassor d’Yerville, D. Cassagne, and C. Jouanin, Appl. Phys. Lett. 79, 2312 (2001) TM3 Left-Handed Materials: Recent Progress and Perspectives I. V. Shadrivova, A. A. Zharova,b, A. A. Sukhorukova, and Yu. S. Kivshara aNonlinear Physics Group, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200, Australia bInstitute for Physics of Microstructures, GSP-105 Nizhny Novgorod, Russia Left-handed materials (LHM) or materials with negative refraction received much attention due to many recent experimental demonstrations, even though they were predicted theoretically almost 40 years ago [1]. LHMs are artificially created structures with simultaneously negative dielectric permittivity and magnetic permeability. In such media electromagnetic waves have the electric field, the magnetic field, and the wave vector forming a left set of vectors in contrast with conventional materials, where these vectors form a right set. As a result, in LHM all waves are backward, i.e. the wave front propagates in the direction opposite to that of the energy flow. The most famous properties of LHMs are negative refraction, reversed Doppler effect, and reversed Vavilov-Cherenkov effect. In this talk, we overview the basic properties of LHMs and recent experimental results as well as discuss possible applications. All types of LHMs do not exist in nature, but they are artificial composite structures containing arrays of metallic resonators with the negative parameters in a microwave frequency range. We underline requirements to the composite structures which make these composites left-handed. Also, we present our recent results demonstrating a number of novel phenomena in LHMs, such as nonlinear switching of material properties between left- and right-handed types, effective second-harmonic generation in novel geometries, nonlinear lenses, and photonic crystals based on LHMs with a novel type of the bandgap. We show that nonlinear magnetic phenomena are strongly enhanced in LHM composites. 1. V. G. Veselago, Usp. Fiz. Nauk 92, 517 (1967) [Sov. Phys. Usp. 10, 509 (1968)]. TM4 The Effects of GaN Capping Layer Thickness on Electrical Properties of Two-dimensional Electron Gas in GaN/AlGaN/GaN Heterostructures A. Asgari♣, L. Faraone School of Electrical, Electronic and Computer Engineering, The University of Western Australia, Crawley, WA 6009, Australia In this article we present a study of the effect of GaN capping layer thickness on the two-dimensional electron gas (2DEG) electrical properties. This study is undertaken using a fully numerical calculation for unintentionally doped GaN/AlxGa1-xN/GaN heterostructures with different Al mole fraction in the AlxGa1-xN barrier, and for various values of barrier layer thickness [1,2,3]. The results of our analysis clearly indicate that increasing the GaN capping layer thickness leads to a decrease in the 2DEG density. Furthermore, it is found that the room temperature 2D-electronmobility reaches a maximum value of approximately 1.8x103 cm2/Vs for GaN capping layer thickness grater than 500 Å with an Al0.32Ga0.68N barrier layer of 200 Å thick. In contrast, for same structure, the 2DEG density decreases monotonically with GaN capping layer thickness, and eventually saturates at approximately 6x1012 cm-2 for capping layer thickness greater than 500 Å. A comparison between our calculated results with published experimental data is shown to be in good agreement for GaN capping layers up to 500 Å thick. PACS: 72. 10. –d; 73. 20. –r; Keywords: mobility; AlGaN/GaN; capping layer; HFET. 1 A. Asgari, M. Kalafi, and L. Faraone, J. Appl. Phys. (in press) 2 M. Kalafi and A. Asgari, Physica E 19, 321 (2003). 3 I. P. Smorchkova, L. Chen and T. Mates, L. Shen and S. Heikman, B. Moran, S. Keller, S. P. DenBaars and J. S. Speck, and U. K. Mishra, J. Appl. Phys. 90, 5196 (2001). ♣ asgari@ee.uwa.edu.au TM5 Calcite Microcrystals in the Pineal Gland of the Human Brain: Second Harmonic Generators and Possible Piezoelectric Transducers Sidney B. Lang Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel A new form of biomineralization in the pineal gland of the human brain has been studied. It consists of small crystals that are less than 20 µm in length and that are completely distinct from the often-observed mulberry-type hydroxyapatite concretions. Cubic, hexagonal and cylindrical morphologies have been identified using scanning electron microscopy. Energy dispersive spectroscopy, selected-area electron diffraction and near infrared Raman spectroscopy established that the crystals were calcite. Experiments at the European Synchrotron Radiation Facility (ESRF) to study the biomineralization showed the presence of sulfur originating from both sugars and proteins. Other studies at the ESRF furnished information on the complex texture crystallization of the calcite. With the exception of the otoconia structure of the inner ear, this is the only known non-pathological occurrence of calcite in the human body. The calcite microcrystals are believed to be responsible for the previously observed second harmonic generation (SHG) in pineal tissue sections. There is a strong possibility that the complex twinned structure of the crystals may lower their symmetry and permit the existence of a piezoelectric effect. TM6 Magnetic Materials for Hyperthermic Cancer Treatment K.M. Spiers, J.D. Cashion, K.A. Gross and S.J. Harker School of Physics and Materials Engineering, Monash University, Victoria 3800, Australia. One method of hyperthermic treatment of tumours is by hysteresis heating of a magnetic implant. This project aims at developing a suitable combination of magnetic material and AC magnetic field which could provide a means of treating deep-seated cancers such as liver cancer. The first part is the production of a smooth-shelled magnetic powder, of micrometre dimensions, which can be introduced by injection into a suitable artery. Magnetite, Fe3O4, and maghemite, γ-Fe2O3, are the prime candidates. Since the heating power is proportional to the frequency, the second part is to develop an AC magnet with sufficient strength and which is capable of operating at suitable frequencies. Most work to date has used air-cored solenoids, but we are trialling a pole-piece electromagnet system which will provide a more focussed magnetic field and hence reduce the resistive heating of nearby tissue. Samples of magnetite were produced from a solution of FeSO4.7H2O by adding KOH/KNO3. The washed and dried precipitate was heated in flowing air to convert the magnetite to maghemite. XRD analysis confirmed the structures. Squid measurements were taken at 40oC in fields of ±24 kA/m (±300 Oe) to determine the hysteresis loop area. Maghemite produced the larger hysteresis area. Mössbauer spectra of the maghemite showed a quite symmetrical sextet structure for which a left and right sextet gave a better fit than did an inner and outer sextet. However, some other workers [e.g. 1,2] have obtained distinctively asymmetrical sextets. There is disagreement in the literature regarding the extent to which ordering of the iron vacancies occurs and it probably preparation dependent. Further fitting and modelling of the spectra are being undertaken to try and determine how much information can be obtained about vacancy ordering in the maghemite structure. [1] R.J. Pollard, Hyperfine Interact. 41, 509 (1988) [2] G.M. da Costa, E. De Grave, L.H. Bowen, R.E. Vandenberghe and P.M.A. de Bakker, Clays and Clay Min. 42 628 (1994). TM7 Nanoparticulate Cobalt/Polymer Complexes for Biomedical Applications M. A. Zalicha, b, T. G. St. Pierrea, V. V. Baranauskasb and J. S. Riffleb a School of Physics, The University of Western Australia, Western Australia 6009, Australia. b Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA The preparation of cobalt nanoparticles is of great interest for biomedical applications owing to their high magnetic susceptibility. Of the transition metals, cobalt (bulk) has one of the largest magnetic susceptibilities per gram of material (1400 emu cm-3); however, cobalt readily oxidizes to form an antiferromagnetic oxide. The presence of antiferromagnetic cobalt oxide on the surface of cobalt metal detracts from the magnetic response of the material. Protecting cobalt nanoparticles against oxidation would be advantageous in preparing highly responsive core elements for developing technologies to address retinal detachment disorders, targeted drug delivery and toxin removal from biological fluids. Cobalt nanoparticles (~10 nm) were prepared by the thermal decomposition of dicobalt octacarbonyl in poly(styrene-b-4-vinylphenoxyphthalonitrile) nanoreactors. A portion of the sample was subsequently pyrolyzed at 700 oC for 4 hours. The magnetic properties of the pre- (sample 1) and post-pyrolyzed (sample 2) materials were investigated using SQUID magnetometry. Transmission electron microscopy (TEM) was used to probe the structure and chemistry of the materials while small angle x-ray scattering (SAXS) was used to investigate particle size and distribution. Magnetic measurements indicated that each sample contained both magnetically blocked and unblocked particles. Zero-field-cooled/field-cooled hysteresis loops at 5K indicated the presence of a cobalt oxide layer in sample 1, whereas sample 2 contained little or no cobalt oxide. In addition, the pyrolyzed sample was found to have a high saturation magnetization of 71 emu/g sample (sample 2). In conclusion, the data show that pyrolysis of polymer coatings around metallic cobalt nanoparticles can produce coatings that protect the nanoparticles from oxidation while retaining a high magnetic susceptibility. TM8 Computer Simulation Studies of the Rheology of Soft Condensed Matter P. J. Daivis, I. K. Snook, M. L. Matin, T. Kairn and M. McPhie Department of Applied Physics, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001, Australia. The rheology of soft condensed matter systems, such as polymer melts, polymer solutions and colloidal dispersions, is a subject of enduring interest - not only because of its importance in materials processing technology, but also because of the fascinating theoretical challenges it presents. Many of the rheological features possessed by these systems, such as normal stress differences, non-Newtonian viscosity and elasticity, are spectacularly evident on the macroscopic scale, but these properties are also crucial to emerging modern technologies such as micro- and nano-fluidics. Over the last seven years, we have studied many different aspects of the rheology of soft condensed matter systems using non-equilibrium molecular dynamics computer simulation techniques. Of particular importance, has been our development of a new algorithm for studying elongational flow [1], a comparison of the planar elongational and shear flow rheology of molecular fluids [2], our examination of the approach to the Brownian limit in colloidal fluids [3], and our detailed investigation of the concentration dependence of the viscosity and normal stress differences in short-chain polymer solutions [4]. In this paper, we review the results of these investigations, discuss the current capabilities and limitations of non-equilibrium molecular dynamics simulations, and discuss our current work and future directions. 1. B. D. Todd and P. J. Daivis, Comp.Phys. Commun. 117, 191 (1999). 2. P. J. Daivis, M. L. Matin and B. D. Todd, J. Non-Newtonian Fluid Mech. 111, 1 (2003). 3. I. Snook, B. O’Malley, M. McPhie and P. Daivis, J. Molec. Liq. 103-104, 405 (2003). 4. T. Kairn, P. J. Daivis, M. L. Matin and I. K. Snook, accepted, Polymer (2004). TM9 A Novel In-Line Micro-Fourier Rheometer J.A. Glasscock and R.S. Smith CSIRO Telecommunications and Industrial Physics PO Box 218 Lindfield, NSW 2070, Australia. A new rheometer has been designed which is capable of being used in industrial process flows. This instrument is able to measure the rheological parameters of a process fluid in a very short time across a frequency range of at least two orders of magnitude in situ. Product quality can be monitored and maintained through rapid manipulation of process variables in response to product fluctuations that are visible as changes in the measured rheological properties of the fluid. The rheometer is constructed such that no process fluid can be trapped in the measurement volume which would lead to errors in subsequent measurements due to fouling or contamination. All parts of the rheometer in contact with the process stream are stainless steel, allowing for the rigorous cleaning procedures commonly required in industry. The operation of this rheometer is described and results from measurements of flowing sunflower oil are presented [1]. The instrument shows an excellent level of reproducibility and its ability to capture and release discrete samples is demonstrated. Static (no flow) measurements have been undertaken on the viscoelastic standard SRM 2490 supplied by NIST [2] in order to compare the results obtained by the in-line micro-Fourier rheometer with those obtained by NIST using a common controlled strain rheometer. The rheological data was compared using a correlation analogous to the Cox-Merz rule [3] using an “effective shear rate". The rheological properties as determined by both instruments were in good agreement showing a similar trend and magnitude. [1] J. Glasscock, R. Smith, J. Vanajek, and J. Winter, Review of Scientific Instruments 74, 4925 (2003). [2] C. Schultheisz and S. Leigh, Tech. Rep. 260143, National Institute of Standards and Technology (2002). [3] D. Doraiswamy, A. Mujumdar, I. Tsao, and A. Beris, Journal of Rheology 35, 647 (1991). TA1 Synchrotron-based Measurements of the Electronic Structure of the Organic Semiconductor Copper Phthalocyanine J. E. Downes MacDiarmid Institute, Victoria University, Wellington, New Zealand. Copper phthalocyanine (CuPc) is a prototypical molecular organic semiconductor that is currently used in the construction of many organic electronic devices such as organic light emitting diodes (OLEDs) [1]. Although the material is currently being used, and despite many experimental [2,3] and theoretical [4] studies, it’s detailed electronic structure is still not completely understood. This is likely due to two key factors. Firstly, the interaction of the Cu 3d and phthalocyanine ligand 2p electrons leads to the formation of a complex arrangement of localized and delocalized states near the Fermi level. Secondly, thin films of the material are subject to damage by the photon beam used to make measurements of their electronic structure. Using the synchrotron-based techniques of soft x-ray emission spectroscopy (XES) and x-ray photoemission spectroscopy (XPS), we have measured the detailed electronic structure of in- situ grown thin film samples of CuPc. Beam damage was minimized by continuous translation of the sample during data acquisition. The results obtained differ significantly from previous XES and ultraviolet photoemission measurements, but are in excellent agreement with recent density functional calculations. The reasons for these discrepancies will be explained, and their implications for future measurements on similar materials will be explored. [1] S.R. Forrest, Chemical Reviews 97, 1793 (1997) [2] I.G. Hill, A. Kahn, Z.G. Soos, et al., Chemical Physics Letters 327, 181 (2000) [3] E.Z. Kurmaev, S.N. Shamin, V.R. Galakhov, et al., Physical Review B (Condensed Matter and Materials Physics) 64, 045211/1 (2001) [4] M.-S. Liao and S. Scheiner, Journal of Chemical Physics 114, 9780 (2001) TA2 New Approaches to Fitting the Mössbauer Spectra of Prussian Blue T. L. Greaves and J. D. Cashion School of Physics and Materials Engineering, Monash University, Victoria 3800, Australia. The Mössbauer spectra of Prussian Blue have traditionally been fitted using one singlet and one doublet, to fit the ferrocyanide and ferric iron sites. However, it is widely accepted in the literature that there are several possible configurations for the ferric site, and each of these should be fitted individually to obtain a meaningful fit. According to the literature, there are two possible Prussian Blue structures, Insoluble Prussian Blue (IPB), Fe3+4[FeII(CN)6]3.14H2O, and Soluble Prussian Blue (SPB) KFe3+[FeII(CN)6]. In IPB there are ten uniquely different coordinations for the ferric site due to many different arrangements of cyanide and water ligands. In SPB there is a more continuous range of ferric sites, due to the presence of potassium ions in voids throughout the cubic lattice. A variety of samples have been prepared which, according to the literature, should have produced three IPB and three SPB samples. However, all the samples appear to be best represented by the IPB structure. A number of different methods have been used to fit the Mössbauer spectra of Prussian Blue, using both Gaussian and Voigtian line shapes. The point charge model has been used to calculate the quadrupole splitting for each ferric site, and the corresponding isomer shifts have been estimated from the partial isomer shifts for each ligand. These theoretical parameters have been used to obtain excellent fits to a range of Prussian Blue samples. Details will be given of improvements in our knowledge of the structure of these well known, but crystallographically complex compounds. TA3 Light Scattering from Spin Wave Excitations in Non-Collinear Thin Film Magnetisation Structures D.C. Crewa and R.L. Stampsa a School of Physics M013, The University of Western Australia, Nedlands WA 6009 We present a theory of Brillouin Light Scattering (BLS) for spectra obtained by scattering from spin wave excitations in highly non-collinear magnetisation structures. As an application we present calculated results for BLS spectra from the spiral state found in exchange coupled hard/soft bilayers during reversal. Effects observable in Stokes/Anti-Stokes ratio asymmetry are described in relation to recent experimental measurements [1]. The thin film structure is modelled as a system of coupled atomic layers in which the material parameters can vary from layer to layer. First, the ground state of the system is found, then a spin spectral density is calculated using a semi-classical Heisenberg model. The cross section for inelastic light scattering spectra is calculated using this spin spectral density together with classical electromagnetic Green's functions appropriate for a multilayer geometry. This model allows the calculation of spin wave excitations in non-uniform magnetisation structures, which are becoming increasingly common in magnetic nanotechnology where two different magnetic materials are exchange coupled across an interface. The layer by layer model can also be applied to the problem of scattering of excitations at disordered interfaces, which is a topic of particular practical as well as basic interest. As an application of the model we consider a recently measured exchange spring system[1]. The exchange spring system has been found to display characteristic structure in the magnetic hysteresis, which allows important information on interface exchange and the effects of magnetic anisotropies to be obtained. Spin wave frequencies can also be used [2] to provide measures of interlayer exchange and anisotropy energies. Here we show the application of the model to data taken from an exchange spring bilayer, Co/CoPt, using BLS. 1. D.C. Crew, R.L Stamps, H.Y Liu, Z.K. Wang, M.H. Kuok, S.C. Ng, K. Barmak, J. Kim, L.H. Lewis, ICM 2003, Rome Italy (2003) Paper 1-ppm14 in press 2. D.C. Crew and R.L. Stamps, J. Appl. Phys. 93 6483 (2003) TA4 Experimental Determination of Lévy Flight Distributions of the Energy Barriers in Spin Glasses N.T. Gorham a, R.C. Woodward a, T.G. St Pierre a, R.L. Stamps a, M.J. Walker b, D. Greig b, and J.A.D. Matthew c a School of Physics, The University of Western Australia, Perth WA, 6009, Australia b Department of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK c Department of Physics, University of York, York, YO10 5DD, UK "Spin glass" was a term originally developed to describe certain magnetic alloys in which there was observed a freezing transition to a low temperature phase where the magnetic moments (or spins) are aligned in fixed but random directions. Although the study of spin glasses is at least three decades old, our current understanding of some very basic issues is still quite limited. Observable characteristics associated with spin glasses are thought to result from the complex dynamics associated with a large number of metastable magnetic states separated by a broad distribution of energy barriers to magnetic reversal. To date, a number of models have been developed which produce this type of energy landscape including the random energy model and the hierarchical energy model. In this study we use a technique previously developed for the study of magnetic nanoparticles [1,2] to characterise the apparent magnetic energy barrier distribution that results from this complex energy landscape for a series of Pd40Ni40-xFexP20 (x=10-20) alloys. The distributions observed are best described by a stretched exponential in the form of a truncated Lévy flight distribution. This form would appear to suggest a hierarchical landscape of apparent energy barriers arising from interactions between randomly oriented magnetic clusters of spins within the material. The degree of stretching of the exponential form of the energy barrier distributions is found to increase with decreasing iron concentration. 1. T.G. St Pierre et al., Phys. Rev. B, 65 (2002) 024436 2. N.T. Gorham et al., J. Magn. Magn. Mat., (in press) TA5 Inductive Measurements of Ferromagnetic Resonance R. C. Woodward*, K. Kennewell, D. C. Crew and R. L. Stamps School of Physics, The University of Western Australia, M013, 35 Stirling Hwy Crawley WA 6009 Australia. The rapid advance in magnetic data storage has driven groundbreaking work in the science that underpins the properties of ferromagnetic materials at high frequencies. Recent work in this area has included the use of precession in order to produce ultra-high speed switching of magnetic elements [1], the generation of excited dynamical structures by application of inhomogeneous field pulses [2], and examination of the propagation of localized spin waves [3]. This paper describes explorations of ultra-fast magnetization dynamics being undertaken at The University of Western Australia. We have studied the differences in magnetization dynamics in simple permalloy films when a sample is excited with sharp pulse compared to the to the dynamics generated by the application of a small amplitude continuous wave signal. We have observed a difference in the resonant frequency determined from these two excitations and will propose reasons for the different resonance responses of the system. Using the ultra-fast techniques described above we have measured dynamical properties that are significantly different to the static properties. These results are explained by the dynamical measurements being made on time scales smaller than the characteristic relaxation time. Future applications of these devices will be to examine broadening of line widths and frequency shifts associated with the excitation of magnetostatic modes, factors limiting quasiballistic reversal and differences between the dynamic and static properties of magnetic materials. 1. H.W. Schumacher, C. Chappert, R.C. Sousa, P.P. Freitas and J. Milat, Phys. Rev. Lett. 90, 017204, (2003) 2. M. Covington, T.M. Crawford and G.J. Parker, Phys. Rev Lett., 89, 237202, (2002) 3. M. Bailleul, D. Olligs and C Fermon, Phys. Rev Lett., 91, 137204, (2002) * corresponding author: woodward@physics.uwa.edu.au TA6 Magnetic Properties, Curie Temperature and Microstructures of PrFeB and NdFeB-based Magnets with Additives by Blending A.Ahmada and I.R.Harrisb a Department of Metallurgical and Materials Engineering, University of Engineering and Technology, Lahore, Pakistan b School of Metallurgy and Materials, The University of Birmingham, UK Since the invention of rare earth based magnets a great deal of research activity has been devoted to improve their magnetic properties by adding alloying elements. In the present study PrFeB and NdFeB-based magnets were made with the additives Co, Al, V, Co-Al (combined addition) and Co-Cu (combined additions) by conventional powder metallurgical process. However the additions of these elements were made by powder blending technique. By blending powders prior to sintering a wide range of compositions can be assessed rapidly using only a small number of starting alloys. The properties of the blended magnets produced have been compared with the magnets produced from alloys modified at a pre- casting stage. The paper describes the microstructure, domains structure, magnetic properties and Curie temperature of the sintered magnets. It has been found that blending is an effective way of adding elements to RFeB alloys. The magnetic properties and Curie temperature of blended magnets have been improved by Co, Co-Al and Co-Cu additions. The coercivity of as-sintered Pr-based magnets after these additions has been found to be better than those of the corresponding Nd-based magnets. Oral Sessions Abstracts Friday 6 February FM1 The Fabrication of Nano-Scale Devices in Silicon F.J. Ruess, M.Y. Simmons, L. Oberbeck, K.E.J. Goh, A.R. Hamilton, T. Hallam, N. J. Curson and R.G. Clark Centre for Quantum Computer Technology, School of Physics, University of New South Wales, Sydney 2052, Australia Over the last three years our group has solved several key issues in the fabrication of nano- scale devices in silicon [1] using an ultra-high vacuum (UHV) scanning tunneling microscope (STM) and silicon molecular beam epitaxy (MBE). These steps include: the placement of single phosphine (PH3) molecules at predefined locations on a silicon surface using STM lithography [2], the controlled phosphorus incorporation from the PH3 molecules into the top layer of the silicon surface with ~ 1 nm accuracy [3] and the encapsulation of P δ-doped layers with minimal segregation using MBE [4,5]. In this talk we present our results for arguably one of the most critical steps of device fabrication using a scanning tunneling microscope – that of connecting the STM patterned buried phosphorus devices outside the vacuum environment to perform electrical measurements. We have achieved this by etching registration markers into the Si surface that allow us to align and contact the nano-scale device fabricated in the UHV system using conventional optical lithography. We present electrical transport data showing a cross over from two-dimensional to one-dimensional behaviour by confining dopants to a 90nm wide quantum wire using STM based lithography. Our results highlight the potential of this fabrication approach for the creation of electronic nano-scale devices in Si down to the atomic level [6] including the realisation of atomically ordered transistors, quantum cellular automata, single atom memory devices and a solid-state quantum computer. 1. J.R. Tucker, T.-C. Shen, Solid State Electronics 42, 1061 (1998). 2. J.L. O’Brien et al., Phys. Rev. B 64, 161401 (2001). 3. S.R. Schofield et al., Phys. Rev. Lett. 91, 136104 (2003). 4. L. Oberbeck et al., Appl. Phys. Lett. 81, 3197 (2002). 5. T.-C.Shen et al., Appl. Phys. Lett. 80 (2002) 1580. 6. F.J. Ruess et al., manuscript in preparation. FM2 Fabrication of a Novel Silicon Single Electron Transistor for Si:P Quantum Computer Devices S.J. Angusa, C.E.A. Smitha, G.L. Sniderb, E. Gaujaa, A.S. Dzuraka and R.G. Clarka a Centre for Quantum Computer Technology, University of New South Wales, Sydney, NSW 2052, Australia. b Department of Electrical Engineering, University of Notre Dame, IN, USA. Quantum computation relies on the successful measurement of quantum states. Single electron transistors (SETs) are known to be able to perform fast and sensitive charge measurements [1] of solid state qubits. However, due to their sensitivity, SETs are also very susceptible to random charge fluctuations in a solid-state materials environment. In previous dc transport measurements [2], silicon-based SETs have demonstrated greater charge stability than Al/Al2O3 SETs. We have designed and fabricated a novel silicon SET architecture for a comparison of the noise characteristics of silicon and aluminium based devices. The silicon SET described here is designed for controllable and reproducible low temperature operation. It is fabricated using a novel dual gate structure on a silicon-on-insulator substrate. A silicon quantum wire is formed in a 100nm thick high-resistivity superficial silicon layer using reactive ion etching. Carriers are induced in the silicon wire by a back gate in the silicon substrate. The tunnel barriers are created electrostatically, using lithographically defined metallic electrodes (~40nm width). These tunnel barriers surround the surface of the quantum wire, thus producing excellent electrostatic confinement. This architecture provides independent control of tunnel barrier height and island occupancy, thus promising better control of Coulomb blockade oscillations than in previously investigated silicon SETs. The use of a near intrinsic silicon substrate offers compatibility with Si:P qubits in the longer term. 1. M.H. Devoret and R.J. Schoelkopf, Nature 406, 1039 (2000). 2. N.M. Zimmerman, W.H. Huber, A. Fujiwara and Y. Takahashi, Appl. Phys. Lett. 79, 3188 (2001). FM3 The Dependence of the Critical Thickness of an InGaAs/GaAs Multi-layer on Quantum Well and Barrier Thicknesses and Number of Periods M. Madebo, B.F. Usher and J. Rileya Department of Electronic Engineering, La Trobe University, Victoria, 3086, Australia. aDepartment of Physics, La Trobe University. Strained-layer superlatices (SLS’s) and multiple-quantum-wells (MQW’s), in which multilayer structures are grown lattice mismatched to a substrate, but with individual layer thicknesses smaller than their critical thicknesses, have become increasingly important in electronic and optoelectronic device applications. Despite the widespread application of SLS’s and MQW’s, there have been serious shortcomings in previous attempts [1,2] to predict the stability criteria for multi-layered structures. In view of this, Madebo et al [3] have developed a Threading Dislocation Configuration (TDC) model that can be applied to any strained layer structure to predict its critical thickness. This paper uses the TDC model to predict the number of MQW periods and the corresponding GaAs barrier thickness required for a given InGaAs layer thickness if the formation of misfit dislocations is to be avoided. This approach follows the evolution of the threading dislocation’s configuration as each monolayer is added to the structure. It is observed that in MQW structures with strained layer thicknesses less than half the critical thickness, there are ranges of quantum well periods for which the barrier thickness required to forbid the formation of a misfit dislocation is the same. But for thicker strained layers (greater than half the critical thickness) the relationship between the minimum barrier thickness required for a given number of quantum well periods is logarithmic in form. [1] G. Allen Vawter and D. R. Myers, J. Appl. Phys., 65, 4769 (1989). [2] R. Hull, J. C. Bean, F. Cerdeira, A. T. Fiory, and J. M. Gibson, Appl. Phys. Lett., 48, 56 (1986). [3] M. Madebo, B.F. Usher and J.D. Riley, Conference on Optoelectronic and Microelectronic Materials and Devices,” UNSW Sydney, Australia, pp 209, IEEE, Piscataway NJ (2003). FM4 X-ray Absorption and Emission Study of Amorphous and Nanocrystalline GaN Films Containing Buried N2 B.J. Rucka, A. Kooa, F. Buddea, S. Granvillea, A. Bittarb, H.J. Trodahla a School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand. b Industrial Research Ltd, P.O. Box 31-310, Lower Hutt, New Zealand. It has been predicted that amorphous gallium nitride (a-GaN) may possess a well-defined wide band gap, and is thus a potential substitute for the more expensive crystalline form used in short wavelength optoelectronic devices [1]. Experimental investigations of disordered GaN have lent support to this prediction, but the picture is complicated because the properties of the amorphous state are not unique, and instead depend on the exact nature of the disordered structure. We have pioneered a novel ion-assisted growth technique that produces GaN films with a microstructure that ranges from nanocrystalline, with crystallite size of order 3 nm, to fully amorphous, depending on the exact growth conditions. This presentation will give an overview of our research into the properties of disordered GaN, including characterization of the physical structure of the films and their electronic energy levels, and also their photoconductive response. In particular I will focus on synchrotron radiation studies of samples with a range of different microstructures. X-ray absorption spectroscopy (XAS) and x-ray emission spectroscopy (XES) provide particularly powerful tools for examining a sample’s empty and filled electronic energy levels, respectively. The details of the absorption and emission processes make it possible to obtain atom-specific information and to investigate the symmetry of the electronic levels. An example of the information obtained is shown in Figure 1. The thin solid curve shows XAS data, which is a measure of the nitrogen p-projected density of unfilled electronic states in this nanocrystalline GaN sample. The thick solid curve shows XES data from the same sample, which provides complementary information about the occupied valence band states. Although the spectral features are broader in fully amorphous films than in nanocrystalline samples, a well-defined band gap exists in both cases with magnitude similar to that of crystalline GaN. There are additional feature present in both spectra that have no analogue in crystalline GaN. The strong absorption peak near 402 eV and the narrow emission line near 393 eV are related to nitrogen atoms trapped within our disordered films in the form of N2 molecules embedded during growth. The coupling between the trapped N2 and the GaN matrix appears to be weak, although there is some evidence for interaction between the two. 2 1 0 380 390 400 410 420 Photon energy (eV) Figure 1: XAS (thin line) and XES (thick line) spectra of a nanocrystalline GaN film. The large peak in the absorption at 402 eV and the peaks in the emission at 393 eV and just over 400 eV are the signatures of molecular nitrogen trapped within the films. The rest of the spectral features represent the valence (XES) and conduction (XAS) band density of states in the GaN. 1. P. Stumm and D.A. Drabold, Phys. Rev. Lett. 79(4), 677 (1997). XAS or XES (arb. units) FM5 Molybdenum Disulphide (MoS2) – Gallium Arsenide (GaAs) Heterostructures for Solar Cell Applications I.M. Jamieson and G. Jakovidis School of Physics and Materials Engineering, Monash University, Victoria 3800, Australia Heterostructures provide a means of absorbing a greater range of the broad solar spectrum in photovoltaic cells compared with single band gap materials. Several layered transition metal dichalcogenides are potential candidates since they have near ideal top layer band gap energy, high absorption coefficients, long minority carrier lifetimes, and large diffusion lengths [1]. One major problem with heterostructures has been the lattice parameter mismatch leading to misfit dislocations. Such defects act as recombination centres that are detrimental to cell performance. Two dimensional layered materials overcome this difficulty because a weak Van der Waals interaction exists at the interface instead of the usual epitaxial growth, with crystallographic texture an important film structural property. If the layered compounds are to be useful as solar cells then they must be grown in a highly textured manner with the c-axis perpendicular to the substrate. Much effort has been devoted to such growth [2–4], to date there is no method which does not rely on metal particles [5] or substrates that promote precursor phases [6] to achieve this aim. In this study, thin films of a model material from this class, molybdenum disulphide, MoS2, (band gap Eg = 1.8 eV), has been deposited by radio frequency magnetron sputtering and pulsed laser deposition techniques on a gallium arsenide substrate (Eg =1.4 eV). Thin film structures are characterised mainly by angle dispersive x-ray diffraction, scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. These techniques reveal that there exists a region of parameter space where substantial desired bulk texturing of MoS2 takes place without the need for metal or precursor phases. It was found that higher substrate temperatures, lower power density and higher sputtering gas pressures favoured the desired texture. [1] A. Aruchamy, (Ed.), Photoelectrochemistry and photovoltaics of Layered Semiconductors, (Kluwer Academic Publishers, Dordrecht, 1992). [2] P.A. Bertrand, J. Mater. Res. 4, 180-4, (1989). [3] J. Moser and F. Levy, J. Mater. Res. 7, 734-40, (1992). [4] E. Gourmelon, J.C. Bernede, J. Pouzet and S.Marsillac, Journal of Applied Physics 87, 1182-6, (2000). [5] J.C. Bernede, J.Pouzet, E. Gourmelon and H. Hadouda, Synthetic Metals 99, 45-52, (1999). [6] N. Barreau, J.C. Bernede, J. Pouzet, M. Guilloux-Viry and A. Perrin, Physica Status Solidi A 187, 427-37, (2001). FM6 Nature of the Peierls- to Mott-Insulator Transition in One Dimension H. Fehskea, G. Welleinb, A. Weissec, G. Hagerb, A. P. Kampfd, M. Sekaniad, A. R. Bishope aInstitut für Physik, Ernst-Moritz-Arndt Universität Greifswald, Greifswald, Germany. bRegionales Rechenzentrum, Friedrich-Alexander-Universität Erlangen, Erlangen, Germany. cSchool of Physics, The University of New South Wales, Sydney, Australia. dInstitut für Physik, Universität Augsburg, Augsburg, Germany. eLos Alamos National Laboratory, Los Alamos, New Mexico, U.S.A. In order to clarify the physics of the crossover from a Peierls insulator to a correlated Mott- Hubbard insulator, we analyze ground-state and spectral properties of the one-dimensional half-filled Holstein-Hubbard model using quasi-exact numerical techniques. In particular the spin and charge excitation gaps are determined by a density-matrix renormalization group finite-size scaling analysis. Moreover we calculate the spin- and charge structure factors, the optical conductivity as well as the photoemission and inverse photoemission spectra and use these quantities to establish the phase diagram of the model. While polaronic features emerge only at strong electron-phonon couplings, pronounced phonon signatures, such as multi- quanta band states, can be found in the Mott insulating regime as well. In the adiabatic limit the Peierls-Mott transition is connected to the band to Mott insulator transition of the ionic Hubbard model. Depending on the strengths of the electron-phonon coupling and the Hubbard interaction this transition is either first order or evolves continuously across an intermediate phase with finite spin, charge, and optical excitation gaps. H. Fehske, A. P. Kampf, M. Sekania, and G. Wellein, Eur. Phys. Jour. B 31, 11 (2003). H. Fehske, G. Weillein, G. Hager, A. Weiße and A. R. Bishop, submitted to Phys. Rev. Lett. FM7 Minority-Spin Band Gap of Half-Metallic NiMnSb H.J. Trodahla, C.E.A. Grigorescub, N. Stricklandc and A. Bittarc a MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University, Wellington, New Zealand. b Institute for Research and Development of Optoelectronics, Bucharest, Romania . c Industrial Research Ltd., Lower Hutt, New Zealand NiMnSb is expected to be a ferromagnetic half metal, an expectation that is based in part on band structure calculations. We report optical conductivity studies of the band structure for a film prepared by pulsed laser deposition onto a Si substrate held at a relatively low temperature required for some device applications, films which are susceptible to site disorder associated with the vacant site in this half-Heusler compound. We demonstrate that the direct interband transitions are essentially unshifted in comparison with bulk material, though they are somewhat broadened. Below the direct-transition absorption edge we report the presence of indirect transitions between the Fermi energy (Ef) and the extrema of the minority-spin valence and conduction bands, providing a measure of the band edge energies. Both of these edges appear closer to Ef than is seen in well-ordered bulk NiMnSb, with the conduction band minimum showing weight at only 200 cm-1 above Ef, close enough to have substantial occupation at ambient temperature. FM8 Transport in Layered Materials: Polarons and Angular Magneto-Resistance Urban Lundina and Ross H. McKenziea a Department of Physics, University of Queensland, Brisbane Qld 4072, Australia. Many of the most interesting strongly correlated materials have a layered crystal structure and highly anisotropic electronic properties. This talk will address two striking properties of this class of materials: The difference in temperature dependence of interlayer and intralayer transport, and the appearance of so called ''Magic Angles'' (MA) in quasi-one-dimensional organic conductors. We have developed a model, based on coherence of quasi-particles, that is capable of explaining many aspects of the different temperature dependence. The quasi- particles within each layer has two contributions, one from coherent states (dominant at low temperatures) and another from incoherent states (dominant at higher temperatures). The temperature dependence comes from scattering of the quasi-particles on phonons (in a polaron model). At low temperatures the polarons are coherent and occasionally scatters off phonons in the layers, but at higher temperatures bound, incoherent, polarons exist on each site. We extract information about the resistivity, spectral function, optical conductivity, and thermopower, quantities which can be directly measured in experiments [1]. For the quasi- one-dimensional materials we will show how incoherent transport between the conducting chains gives rise to the MA seen in many organic quasi-one-dimensional materials when a magnetic field is applied [2]. 1. Urban Lundin, Ross H. McKenzie and V. White, Phys. Rev. B 68, 81101(R) (2003). 2. Urban Lundin and Ross H. McKenzie, (in manuscript) FM9 Density Functional Theory Calculation of Band-gaps in Diamond Nanowires S.P. Russo, A.S. Barnard and I.K. Snook Department of Applied Physics, RMIT University, Melbourne, Australia. Diamond has been found to possess remarkable electronic and chemical properties, and development of diamond nanowires are now considered feasible [1,2]. In an attempt to predict the electronic properties of diamond nanowires, we have used ab initio (plane wave-DFT) techniques [3] to calculate the T=0oK band-gaps of structurally stable hydrogenated and dehydrogenated diamond nanowires, with cubic, cylindrical and dodecahedral morphology. Our results indicate the nanowire band-gap dependence on structural parameters such as the nanowire diameter, surface morphology and surface hydrogenation. [1] A.S. Barnard, S.P.Russo, and I.K.Snook , Nano Letters 3 (2003) 1323 [2] A.S. Barnard, S.P.Russo, and I.K.Snook, Physical Review B 68 (2003) 073406 [3] G. Kresse and J. Hafner, Phys. Rev. B 54 (1996) 11 169 Poster Session Abstracts Wednesday 4 February WP1 The Effects of Multiple Scattering on the Analysis of USANS Data W. K. Bertram Materials Division, Australian Nuclear Science and Technology Organisation, Menai, NSW 2234, Australia Small-angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS) are widely used to investigate the micro- and nano-structure of condensed matter. However, measurements on materials such as cements, clays etc. are often affected by multiple scattering. If a substantial number of neutrons experience more than one scattering event within a sample, the result is broadening of the angular distribution profile. Often samples cannot be made thin enough to guarantee single scattering and even in cases where it is possible to make thin samples, surface effects can sometimes lead to results that are not representative of the bulk material. In addition, for many SANS and USANS measurements there is no reliable method for determining whether or not a sample is thin enough to produce predominantly single scattering. Here we present a new method for extracting singly-scattered data from data affected by multiple scattering. One of the main advantages over our previously published method [1] is that this method is much easier to apply as it requires no initial modeling and fitting of the data. [1] Sabine T. M. and Bertram W. K., Acta Cryst. A 55 (1999), 500-507 WP2 Crystallization in Polydisperse Colloidal Suspensions Stephen Martina, Gary Bryanta and William van Megena a Department of Applied Physics, RMIT University, Melbourne 3001, Australia. Crystallization and glass formation in colloidal hard spheres has been a very active area of research over the last 15-20 years. For most of this time particle polydispersity has been considered to be a minor concern in these studies. However, over the last few years an increasing number of simulations, theoretical work and experiments have shown that consideration of the polydispersity is critical in understanding these phenomena [1-4]. In this paper we provide an overview of recent crystallization studies [5-6] on particles with two very different particle size distributions. These particles exhibit very different equilibrium crystal structures and crystallization kinetics. Based on these measurements and time lapse photographs, we propose a growth mechanism whereby crystallization occurs in conjunction with a local fractionation process near the crystal-fluid interface, which significantly alters the kinetics of crystallite nucleation and growth. This fractionation effect becomes more significant as polydispersity or skewness increases. The unusual crystal structures observed are explained using a schematic model that explains the structure in terms of stacks of planes, which are unregistered due to a high incidence of stacking faults caused by the incorporation of a large number of small particles. [1] D.A. Kofke and P.G. Bolhuis, Phys. Rev. E 59, 618, 1999. [2] P. Bartlett, J. Phys.: Condens. Matter 12, A275, 2000. [3] S. Auer and D. Frenkel, Nature, London, 413, 711, 2001. [4] S.R. Williams, I.K. Snook, and W. van Megen, Phys. Rev. E, 64, 021506, 2001. [5] S. Martin, G. Bryant and W. van Megen, Phys. Rev. E. 67, 061405, 2003. [6] S. Martin, G. Bryant and W. van Megen, Phys. Rev. Lett. 90, 255702, 2003. WP3 Studies of Magnetic Structure of La1-xSrxMnO3 Colossal Magnetoresistive Perovskites T.R. Finlayson a, X. Wua, T. Ersez b and J.C. Schulzc a School of Physics and Materials Engineering, Monash University, Victoria 3800, Australia. b Nuclear Technology, ANSTO, Lucas Heights, NSW 2234, Australia. c Bragg Institute, ANSTO, Lucas Heights, NSW 2234, Australia. This class of materials, based on the compound LaMnO3, continues to be the focus of attention because they exhibit colossal magnetoresistance (CMR) [1] which could lead to possible applications in magnetic recording and field sensors. In addition to the technological applications, the materials are important from a fundamental point of view due to the strong correlations between transport, structural and magnetic behaviour. The origin of the CMR effect has been attributed to the presence of magnetic polarons above the ferromagnetic ordering temperature, Tc. From recent research, using a combination of powder neutron diffraction, polarisation analysis and small-angle neutron scattering together with magnetic measurements, we present diffuse scattering, spin dynamics and lattice and magnetic correlations results for the La1-xSrxMnO3 (x=0.125 and 0.175) compounds. The diffuse scattering in the neutron diffraction patterns increases as the temperature approaches Tc from low temperature and continues to increase above Tc. The scattering peak in the forward direction above Tc (Tc, <110> and <111>). As these measurements are resolved in both energy and momentum and the measured intensity is directly proportional to the momentum density they provide a comprehensive comparison for current solid state calculations. Cu 100 Cu 110 Cu 111 0 0 0 -5 -5 -5 -10 -10 -10 0 0.5 1 1.5 2 2.5 3 0 0.5 1 1.5 2 2.5 3 0 0.5 1 1.5 2 2.5 3 momentum (au) momentum (au) momentum (au) The data are compared to the full-potential linear muffin-tin orbital (FP-LMTO) method within the framework of density functional theory, which is a first-principles band structure method [1]. EMS gives a very complete description of the electronic structure of copper that includes peak intensities, peak shapes (width and asymmetries) as well as dispersion, and satellite intensities, which provide detailed tests of electronic structure theories. [1] A. S. Kheifets, D. R. Lun, S. Yu. Savrasov, J.:Phys Condens. Matter, 11, 6779 (1999) TP20 Fast Simulation of a Quantum Phase Transition in an Ion-trap Realisable Unitary Map J P Barjakatevic a, G Milburn a, R H McKenzie a a University of Queensland We demonstrate a method of exploring the quantum critical point of the Ising universality class using unitary maps that have recently been demonstrated in ion trap quantum gates. We reverse the idea with which Feynman conceived quantum computing, and ask whether a realisable simulation corresponds to a physical system. We proceed to show that a specific simulation (a unitary map) is physically equivalent to a Hamiltonian that belongs to the same universality class as the transverse Ising Hamiltonian. We present experimental signatures, and numerical simulation for these in the six-qubit case. TP21 Magnetic Materials for Hyperthermic Cancer Treatment K.M. Spiers, J.D. Cashion, K.A. Gross and S.J. Harker School of Physics and Materials Engineering, Monash University, Victoria 3800, Australia. One method of hyperthermic treatment of tumours is by hysteresis heating of a magnetic implant. This project aims at developing a suitable combination of magnetic material and AC magnetic field which could provide a means of treating deep-seated cancers such as liver cancer. The first part is the production of a smooth-shelled magnetic powder, of micrometre dimensions, which can be introduced by injection into a suitable artery. Magnetite, Fe3O4, and maghemite, γ-Fe2O3, are the prime candidates. Since the heating power is proportional to the frequency, the second part is to develop an AC magnet with sufficient strength and which is capable of operating at suitable frequencies. Most work to date has used air-cored solenoids, but we are trialling a pole-piece electromagnet system which will provide a more focussed magnetic field and hence reduce the resistive heating of nearby tissue. Samples of magnetite were produced from a solution of FeSO4.7H2O by adding KOH/KNO3. The washed and dried precipitate was heated in flowing air to convert the magnetite to maghemite. XRD analysis confirmed the structures. Squid measurements were taken at 40oC in fields of ±24 kA/m (±300 Oe) to determine the hysteresis loop area. Maghemite produced the larger hysteresis area. Mössbauer spectra of the maghemite showed a quite symmetrical sextet structure for which a left and right sextet gave a better fit than did an inner and outer sextet. However, some other workers [e.g. 1,2] have obtained distinctively asymmetrical sextets. There is disagreement in the literature regarding the extent to which ordering of the iron vacancies occurs and it probably preparation dependent. Further fitting and modelling of the spectra are being undertaken to try and determine how much information can be obtained about vacancy ordering in the maghemite structure. [1] R.J. Pollard, Hyperfine Interact. 41, 509 (1988) [2] G.M. da Costa, E. De Grave, L.H. Bowen, R.E. Vandenberghe and P.M.A. de Bakker, Clays and Clay Min. 42 628 (1994). TP22 Mixed-Spin S=(½,1) Quantum Ferrimagnet at Zero Temperature Weihong Zheng and J. Oitmaa School of Physics, The University of New South Wales, Sydney NSW 2052, Australia. Ferrimagnets are materials where ions on different sublattices have opposing magnetic moments which do not cancel in the ordered phase [1]. There is growing interest in such systems, both from fundamental physics and through their technological potential. Arguably the simplest such structures are bipartite (A,B) lattices structures with S A ≠ SB . Realizations include bimetallic chains, rare-earth nickelates R2BaNiO5 and an Fe-Ni cyanide bridged network [2]. In this work [3] we investigate bipartite AB systems with S A = 1/ 2, SB = 1 in 1-dimension, 2- dimensions (square lattice) and 3-dimensions (simple cubic lattice). The model used is the Heisenberg antiferromagnet with nearest neighbour exchange, including exchange anisotropy H = J ∑[S z z x x y yi S j + γ (Si S j + Si S j )] We use a combination of high-order linked cluster expansions and second-order spin wave theory to calculate the ground state energy, sublattice magnetizations and magnon energies. At the isotropic point γ = 1 one of the two magnon branches becomes gapless, with quadratic dispersion while the other remains gapped. Agreement between series results and second- order spin wave theory is found to be excellent. 1 W.P. Wolf, Rep. Prog. Phys. 24, 212 (1961). 2 P.J. Koningsbruggen, et al. Inorg. Chem. 29, 3325(1990), A. Zheludev et al. Phys. Rev. Lett. 80, 3630(1998), J.W. Park et al. cond-mat/0206319. 3 W. Zheng & J. Oitmaa, Phys. Rev. B67, 224421(2003). TP23 Phase Diagram of the BCC S=½ Heisenberg Antiferromagnet with First and Second Neighbour Exchange J. Oitmaa and Weihong Zheng School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia. The occurrence of competing exchange interactions in magnetic materials can give rise to a rich variety of magnetic ordered states, and of phase transitions between them. Studies of such phenomena, within the classical "molecular-field" approximation go back half a century [1] or more. It is perhaps surprising that open questions remain, but, at least for quantum models, this is the case. In this work [2] we use linked-cluster series expansions, both at T=0 and at high temperature, to analyse the phase structure of the spin-1/2 Heisenberg antiferromagnet on the body- centred-cubic lattice with first and second-neighbor exchange H = J1∑Si ⋅ S j + J 2 ∑Sk ⋅ S l [kl ] At zero temperature we find a first-order quantum phase transition at J 2 / J1 = 0.705 ± 0.005 between AF1 (Néel) and AF2 ordered phases. The high temperature series yield quite precise estimates of the critical line separating the AF1 and paramagnetic phases, and an apparent critical line for the AF2 phase, with a bicritical point at J 2 / J1 = 0.71, kBT / J1 = 0.34 . The possibility that this latter transition is first-order cannot be excluded. 1 J.S. Smart, Effective Field Theories of Magnetism, (Saunders, Philadelphia, 1966). 2 J. Oitmaa & W. Zheng, submitted to Phys. Rev. B. TP24 Comparative Numerical Study of Localization in Disordered Electron Systems G. Schuberta, A. Weisseb and H. Fehskea aInstitut für Physik, Ernst-Moritz-Arndt Universität Greifswald, Greifswald, Germany. b School of Physics, The University of New South Wales, Sydney, Australia. Taking into account that a proper description of disordered systems should focus on distribution functions, the authors develop a powerful numerical scheme for the determination of the probability distribution of the local density of states (LDOS), which is based on a Chebyshev expansion with kernel polynomial refinement and allows the study of large finite clusters (up to 1003 ). For the three-dimensional Anderson model it is demonstrated that the distribution of the LDOS shows a significant change at the disorder induced delocalization- localization transition. Consequently, the so-called typical density of states, defined as the geometric mean of the LDOS, emerges as a natural order parameter. The calculation of the phase diagram of the Anderson model proves the efficiency and reliability of the proposed approach in comparison to other localization criteria, which rely, e.g., on the decay of the wavefunction, the inverse participation number or the conductance. In addition the method is successfully applied to the study of the metal-insulator transition in one dimensional systems with correlated disorder and to the quantum percolation problem on a simple cubic lattice. G. Schubert, A. Weisse, and H. Fehske, cond-mat/0309015 TP25 Structure Factors for the Alternating Heisenberg Chain C.J. Hamer and Weihong Zheng University of New South Wales and R.R.P. Singh UC Davis We develop a linked cluster method to calculate the spectral weights of many-particle excitations at zero temperature. The dynamical structure factor, which is measured in neutron scattering experiments, is expressed as a sum of “exclusive” structure factors, each representing the contribution of a specific excited state. We apply these methods to the alternating Heisenberg chain, where complete wave-vector and frequency dependent spectral weights for one- and two-particle excitations (continuum and bound states) are calculated near the dimerized limit (λ = 0). We also examine the variation of the spectral weights as the uniform chain (λ = 1) is approached. In agreement with Schmidt and Uhrig, we find that the spectral weight is dominated by 2-triplet states, even at λ = 1, which implies that a description in terms of triplet-pair excitations remains a good quantitative description even for the uniform, undimerized chain. TP26 Superconducting Correlations and Model System Design Y. Hancock and D.M. Paganin School of Physics and Materials Engineering, Monash University, Victoria 3800, Australia. The mechanism which leads to Cooper pair formation in high TC superconducting systems is a point of intense controversy and remains a “hot topic” in current condensed matter research [1]. Recently the trend has been to move away from conventional BCS theory and to use a range of minimal models, which assume very little about the pair formation mechanism [2]. In this case pair formation arises as an emergent phenomenon, thereby giving greater freedom for uncovering new microscopic effects. In this work the superconducting (s-wave) pair correlation functions are calculated for small ring cluster systems of up to 12 atoms. The results are determined by exact diagonalization of various single band Hubbard-type Hamiltonians, namely, the Hirsch (correlated hopping) model [2], the t-t′-U Hubbard model (with next nearest neighbour hopping) [3] and the anisotropic extended Hubbard model [4]. Combinations of these systems and the role of inhomogeneity are studied with the Hubbard model [5] used as the base comparison. The pair correlation is found to be strongly influenced by variations in model energetics. The underlying microscopic mechanisms for these trends are explained together with predictions for new cluster designs that exhibit enhanced pairing effects. 1. A.A. Aligia and L. Arrachea, Phys. Rev. B 64, 214518 (2001). 2. J.E. Hirsch, Phys. Rev. B 48, 3327 (1993); http://physics,ucsd.edu/~jorge/jh.html. 3. M.E. Torio, A.A. Aligia and H.A. Ceccatto, Phys. Rev. B 67, 165102 (2003). 4. H. Otsuka, Phys. Rev. Lett. 84, 5572 (2000). 5. J. Hubbard, Proc. Roy. Soc. London A 276, 238 (1963). TP27 Low-lying Excitations in Odd-legged Spin-½ Tubes with Strong Rung Coupling A. Lüschera, R. Noackb, G. Misguichc, V. Kotovd, F. Milad a School of Physics, University of New South Wales, Sydney 2052, Australia b Institut für Theoretische Physik III, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany c Service de Physique Théorique, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France d Institut de théorie des phénomènes physiques, École Polytechnique Fédérale de Lausanne BSP, CH-1015 Lausanne, Switzerland We study the low-lying excitations of odd-legged spin-½ tubes with nearest-neighbour Heisenberg interactions Si⋅• Sj in the limit of strong rung coupling. The periodic boundary conditions applied in the rung direction give rise to an effective model with spin and chirality degrees of freedom, interacting with one another by a geometry dependent coupling constant. By means of DMRG calculations, we show that spin and chirality excitations are gapped. These gaps exhibit a power-law dependence on the coupling strength, which is derived in a mean-field approach and compared to numerical results. The nature of excitations is revealed using Wang's variational approach [1] and the DMRG calculations. Bound soliton states (magnon-like excitations), the deconfinement and the onset of the unbound two-soliton states (spinon-like excitations) are observed in the chirality channel for increasing coupling between spin and chirality degrees of freedom. 1 H.-T. Wang, Phys. Rev. B 64, 174410 (2001). TP28 Photoconductivity in Disordered GaN A. Kooa, B. J.Rucka, H. J. Trodahla, F. Buddea and A. Bittar b a MacDiarmid Institute and School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand b Industrial Research Limited, Lower Hutt, New Zealand Disordered semiconductors and their optoelectronic behaviour are of interest for their potentially exploitable characteristics. Moreover the relationship between the ordering of the sample, the presence of oxygen and hydrogen and the optoelectronic behaviour presents an interesting and complex problem. In the case of gallium nitride with a band gap of 3.4 eV, various degrees of order are able to be produced when depositing thin films by Ion Assisted Deposition (IAD). The introduction of water vapour into the vacuum chamber during deposition induces amorphisation and a significant change in the band edge photoconductive response. More disordered samples exhibit much slower response times, on the scale of hours, and a much stronger response, by several orders of magnitude as shown in the figure below. The difference in recombination characteristics displayed by these results correlates well with the Rose exponents extracted from the intensity dependence of the photoconductivity. 1 amorphous GaN 0.1 0.01 0.001 nanocrystalline GaN 0.0001 Light On Light Off 0 2000 4000 6000 8000 10000 Time (s) Figure 1. Time dependence of photoconductivity for two GaN films. Current (nA) TP29 TP30 Quantum Interference with Heisenberg Spin Chains D. J. Miller a Centre for Time, University of Sydney, NSW 2006. Spins coupled via the Heisenberg interaction on lattices of various dimensions have been of interest in condensed matter physics for many years. Recently it has been shown that systems of that type can be used for quantum computation and quantum communication [1,2]. Modern advances in experimental condensed matter physics have broadened the range of physical objects whose mutual interactions can be described in terms of the simple Heisenberg interaction which was previously associated mainly with the spins of atoms or nuclei. A notable example is the interaction between spins on quantum dots [3]. Consequently, it has become possible to fabricate structures of interacting Heisenberg “spins” which are different from the conventionally studied lattice. The purpose of the present work is to investigate the consequences of using configurations of Heisenberg spins to emulate quantum interference devices equivakent to the 2-slit experiment and the Mach-Zehnder interferometer. As one might expect, it is found that the interference effects are sensitive to the interaction between the spins and this means the effects could lead to practical applications which are discussed. [1] D. P. DiVincenzo, D. Bacon, J. Kempe, G. Buckard and K. B. Whaley, Nature 408, 339 (2000); quant-ph/0005116. [2] S. Bose, Phys. Rev. Lett. 91, 207901 (2003); quant-ph/0212041. [3] G. Buckard, D. Loss and D. P. DiVincenzo, Phys. Rev. B 59, 2070 (1999). TP31 Shockley and Rydberg Surface States and Quantum Wells on the Cu(111) Surface M. N. Read School of Physics, University of New South Wales, NSW 2052, Australia. Adsorbed alkali metals such as Na on (111) noble (and near-noble) metal surfaces form quantum well systems where the electron is trapped between the surface barrier and crystal substrate forming a quasi-2-dimensional electron gas. Such systems can be used as metal- based nanostructured quantum electronic devices. As a preliminary to the study of the surface states of these systems we have calculated the band structure of surface states for the clean Cu(111) surface from just below the Fermi level to 30 eV above it. An advantage for this surface is that the Shockley state is so accurately known from photoemission (PE) data because it occurs in a bulk band gap: the energy is – 0.39(1) eV with respect to the Fermi level at Γ with an effective mass of 0.46(1). This is precisely the energy at which saturation occurs from the image barrier. Also the unoccupied Rydberg resonances have been measured using STM. We have used our layer-by-layer-KKR method to theoretically reproduce these states and resonances. Because we have reproduced bulk band edges with respect to the Fermi level we have been able to determine the vacuum energy level for Fermi energy electrons at Γ , which fixes the barrier height for electrons in this energy region for our theoretical bulk potential. An exponentially saturated image barrier with truncation in the region of the jellium discontinuity is found to reproduce experimental results. This is a different form of saturation from that earlier estimated by an approximation method by other investigators. We have found excited surface features which could elicit the variation of the self-energy of the electron with energy and momentum as well as higher energy variation of the image potential. These higher energy features should be observable in inverse photoemission (IPE) and very low energy electron diffraction (VLEED) and other surface spectroscopies. TP32 Searches for the Electron Electric Dipole Moment and Nuclear Anapole Moments in Solids T.N. Mukhamedjanov, O.P. Sushkov, J.M. Cadogan, V.A. Dzuba School of Physics, University of New South Wales, Sydney 2052, Australia. We consider effects caused by the electron electric dipole moment (EDM) in gadolinium garnets. Our estimates show that the experimental studies of these effects could improve the current upper limit on the electron EDM by several orders of magnitude. We suggest a consistent theoretical model and perform calculations of observable effects in gadolinium gallium garnet and gadolinium iron garnet. It is also possible to probe for nuclear anapole moments in a solid state experiment. We suggest such NMR-type experiment and perform estimates of the expected results. TP33 Apparent Sizes of Solute Atoms and Vacancies in Aluminium from First Principles A. E. Smith and S. Homolya School of Physics and Materials Engineering, Monash University, Victoria 3800, Australia. First-principles methods, including the full potential augmented plane wave method within the the density functional theory scheme [1] and employing the Perdew-Burke-Ernzerhof GGA exchange correlation functional [2], are used to investigate substitutional defects in fcc aluminium. Defects considered include copper, silver and tin atoms, as well as vacancies. Results of ground state calculations are presented for supercells containing one solute atom or vacancy and up to 63 aluminium atoms. The distortion of the fcc lattice by the defect is calculated for each system by minimising ground state energy with respect to supercell lattice parameters and all atomic positions. The optimised supercell geometry is used to calculate the apparent sizes of solute atoms and vacancies, defined either in terms of microscopic or in terms of bulk properties properties of the system. Significant discrepancy between microscopic and macroscopic definitions of apparent defect size is attributable to the long- range nature of the strain in the fcc lattice near defects, which extends well beyond nearest neighbour sites. However, for copper and silver solute atoms the apparent sizes of defects defined in terms of the density of the bulk material show good quantitative agreement with previously reported experimental results. The results also show that the formation of isolated substitutional tin defects is energetically highly unfavourable, as would be expected from experiment [3,4]. 1. P. Blaha et al.,WIEN2K, An Augmented Plane Wave + Local Orbitals Program for Calculating Crystal Properties (Karlheinz Schwarz, Techn. Universität Wien, Austria, 2001). 2. J.P. Perdew, K. Burke, and M. Ernzerhof, Phys.Rev. Lett. 77, 3865 (1996). 3. D. A. Porter and K.E. Easterling, Phase transformations in metals and alloys, Chapman & Hall, (1992). 4. I.J. Polmear, Light Alloys, Butterworth Heinemann, (2000). TP34 Superconducting Spiral Phases in the Two-Dimensional t-J model. Oleg P. Sushkov a and Valeri N. Kotov b a School of Physics, University of New South Wales, Sydney 2052, Australia. b Institute of Theoretical Physics, University of Lausanne, CH-1015 Lausanne, Switzerland The t-J model has been suggested in 1987 by P. W. Anderson and V. J. Emery to describe the essential low-energy physics of the high-Tc cuprates. Formation of spirals in the doped t-J model was proposed by Shraiman and Siggia in 1989. The idea that the spiral state is the ground state of a cuprate attracted a lot of attention in 90s, however the question of stability of the state remained unresolved. Recently the interest in the spiral state was renewed because of the strong experimental indications that at small doping the cuprates behave as spin glasses or even exhibit some kind of magnetic ordering. The data also shows that magnetic ordering and superconductivity coexist. The spin glass behavior is consistent with the spiral scenario: since doping is not uniform the pitch of the spiral is varying from point to point and hence on large scales it leads to spin glass behavior . In the present work we analyse the t-t'-t''-J model. By using chiral perturbation theory we have determined the ground state to be a spiral for small doping δ << 1 near half filling. In this limit our solution does not contain any uncontrolled approximations. We evaluate the spin-wave Green's functions and address the issue of stability of the spiral state, leading to the phase diagram of the model. At t'=t''=0 the spiral state is unstable towards a local enhancement of the spiral pitch, and the nature of the true ground state remains unclear. However, for values of t' and t'' corresponding to real cuprates the spiral state is stable. We show that at δ = 0.119 the spiral is commensurate with the lattice with a period of 8 lattice spacings in agreement with experimental data. Even more important, we have demonstrated that the magnetic spiral and superconductivity coexist. Even though one cannot classify the superconducting gap symmetry according to the lattice representations (s,p,d,...) since the symmetry of the lattice is spontaneously broken by the spiral, the gap always has lines of nodes along (1,1) and (1,-1) directions. TP35 Corrosion Resistance of Organic Layers on GaAs via X-Ray Reflectometry Characterization J.D.Smith, T.R. Finlayson, C. Kirchner and U. Klemradt School of Physics and Materials Engineering, Monash University, Victoria 3800, Australia. Two different solutions of (3-mercaptopropyl) trimethoxysilane (MPT) were deposited on GaAs surfaces to provide passivation against corrosion by oxygen and to prevent AsO 3-3 escape into the surrounding environment. The solutions were compared to each other for their relative corrosion resistance by determining the resultant buried oxide layer and MPT layer thicknesses and densities. All samples were scanned using grazing incidence X-ray reflectometry at DESY, Hamburg, Germany. The samples were prepared under Argon during HCl etching and deposition. It was hoped that the corrosion of the surface and thus the relative thickness of the buried oxide layer could be reduced by changing from ethanol to methanol since ethanol is known to by hydrophilic. Even small quantities of moisture at the GaAs interface can lead to oxidation and corrosion. It was found from the models fitted that all samples had buried oxide layers due to surface corrosion. Further study is required regarding the effectiveness of thiol overlayers against arsenic and oxygen diffusion on the GaAs surface. TP36 New Tools for the Numerical Calculation of Dynamical Correlation Functions at Finite Temperature Alexander Weisse School of Physics, The University of New South Wales, Sydney, Australia. The calculation of dynamical correlation functions, like optical conductivities, spin structure factors and other (linear) response functions, is one of the typical problems in condensed matter physics. In many cases real materials are in a parameter regime where analytical methods are not applicable and therefore the use and development of numerical methods is indispensable. At zero temperature Chebyshev expansion and the Kernel Polynomial Method [1] proved to be a valuable tool for this kind of problems, for both interacting and non-interacting quantum systems. In this contribution we present a non-trivial extension of these methods to finite temperature. To demonstrate the power of the approach we calculate the optical conductivity of non-interacting electrons in a random potential (Anderson model), and transport properties of interacting (1D) quantum models [1] Silver, Roeder, Phys. Rev. E 56, 4822 (1997) [2] cond-mat/0309015 TP37 Does the Probability Density Imply the Equation of Motion? Rotha P. Yu, David M. Paganin and Michael J. Morgan School of Physics and Materials Engineering, Monash University, Victoria 3800, Australia. The laws of physics dictate the evolution of matter and radiation. Quantum mechanics postulates that the matter or radiation is associated with a field whose magnitude is interpreted as the probability density, which is the only observable quantity. In general this field is either a single-component or multi-component complex scalar field, whose laws of evolution may be expressed in the form of partial differential equations. One may ask does the probability density of the complex scalar field imply the evolution of the field? Here we answer this fundamental question by examining a means for measuring the equation of motion of a single- component complex scalar field associated with a non-dissipative and nonlinear system, given measurements of the probability density. Applications of this formalism, to a number of systems in condensed matter physics, will be discussed. TP38 Reactive Ion Etching of Microphotonic Structures J. Du, J. Glasscock, J. Vanajek and N. Savvides CSIRO Telecommunications & Industrial Physics, Lindfield, NSW 2070, Australia Fabrication of microphotonic structures such as planar waveguides and other periodic structures based on silicon technology has become increasingly important due to the potential for integration of planar optical devices. We have fabricated various periodic microstructures on silicon wafers using standard optical lithography and reactive ion etching (RIE). For optical applications the surface roughness and the sidewall angle or steepness of microstructures are the most critical factors. In particular, sidewall roughness of the etched waveguide core accounts for most of the optical propagation loss. We show that by varying the main RIE parameters such as gas pressure, RF power and CF4/Ar/O2 gas composition it is possible to produce microstructures with near-vertical sidewalls and very smooth surfaces. In addition to plasma etching conditions, poor edge quality of the mask often causes sidewall roughness. We employed Ni/Cr metal masks in these experiments for deep etching, and used Ar+ ion milling instead of wet chemical etching to open the mask. This improves the edge quality of the mask and ultimately results in smooth sidewalls. Figure 1. Waveguides etched in silicon Figure 2. Square array etched in silicon using CF4/Ar at 50 W RF power. using CF4/Ar at 50 W RF power. TP39 An Apparent Shift in Optical Constants in Nanostructured Metal Films Overcoated with Insulator: a New class of Multilayer Thin Film Systems A.I. Maaroof and G.B. Smith Department of Applied Physics University of Technology, Sydney PO BOX 123 BROADWAY NSW 2007 email g.smith@uts.edu.au Thin metal films which contain arrays of nano-size voids have interesting optical responses, including higher than expected transmittance and larger than expected delays in electromagnetic energy transport over certain wavelength bands, mainly in the near infra red (NIR). As scattering is not observed an effective homogeneous complex refractive index applies. The result is a strongly elevated real part (from the delays) and strongly reduced imaginary part (from enhanced transmittance) relative to both a void free metal, and a “classical” metal with voids. This far field response depends on void nanostructure, grain size and plasmon frequency of the metal. It is shown that these indices cannot be explained by classical effective medium models which utilise quasi-static electric polarisation. Instead films have their NIR properties dictated by the special surface plasmons that form in the presence of nano-holes. Photon resonance with these excitations enhances delay times and effective response requires a dynamic field treatment at all size scales, since localised surface plasmon currents and associated magnetic fields are present. Sensitivity to surface plasmons is dramatically illustrated when an insulating layer is present on such films. The apparent indices of the metal layer change, in some cases substantially. Classical multilayer thin film models in which each layer’s refractive indices are independent of the neighbouring medium, cannot then be used. Results on two distinct nano-void systems are included, for which super high resolution SEM images from a new LEO SEM will be shown. Measured refractive indices will be used to demonstrate how thin metal layers containing nano-voids depart from the expected response of a metal with voids, to a degree dictated by the refractive index of the neighbouring medium. TP40 Silicon Microphotonic Waveguides V. Ta’eeda, M. J. Steela, C. Grilleta, B. Eggletona, J. Dub, J. Glasscockb and N. Savvidesb a CUDOS, School of Physics, The University of Sydney, NSW 2006, Australia. b CSIRO Telecommunications & Industrial Physics, Lindfield NSW 2070, Australia. Silicon microphotonic devices have been drawing increasing attention in the past few years. The high index-difference between silicon and its oxide (∆n = 2) suggests a potential for high- density integration of optical functions on to a photonic chip. Additionally, it has been shown that silicon exhibits strong Raman nonlinearity [1], a necessary property as light interaction can occur only by means of nonlinearities in the propagation medium. The small dimensions of silicon waveguides require the design of efficient tapers to couple light to them. We have used the beam propagation method (RSoft BeamPROP) to understand the principles and design of an inverse-taper mode-converter as implemented in several recent papers [2-3]. We report on progress in the design and fabrication of silicon-based waveguides. Preliminary work has been conducted by patterning silicon-on-insulator (SOI) wafers using optical lithography and reactive ion etching. Thus far, only rib waveguides have been designed [4], as single-mode ridge-waveguides are beyond the capabilities of conventional optical lithography. We have recently moved to electron beam lithography as the higher resolutions permitted will provide the flexibility to begin fabricating sub-micron waveguides. 1. Ricardo Claps et al., “Observation of Raman emission in silicon waveguides at 1.54um”, Opt. Express, 10(22) 1305-1313, (2002) 2. T. Shoji et al., “Low loss mode size converter from 0.3µm square Si wire waveguides to singlemode fibres”, Electron. Letters, 38 (25), (2002) 3. Laurent Vivien et al., “2-D Taper for low-loss coupling between polarization-insensitive microwaveguides and single-mode optical fibers”, J. Light. Tech., Dec, 2002 4. Olly Powell, “Single-mode condition for silicon rib waveguides”, J. Light. Tech., 20(10), 1851-1855, (2002) Participants PARTICIPANTS Ahmad Akhlaq UET,Lahore, Pakistan aamalik87@hotmail.com TA6 Ain Michael ANSTO mai@ansto.gov.au WP16 Allan Rodney UTS Rodney.S.Allan@uts.edu.au Angus Susan UNSW susan.angus@student.unsw.edu.au TP11, FM2 Armstrong Kevin AVT Services Exhibitor Armstrong Nicholas UTS nicholas.armstrong@uts.edu.au WA5 Asgari Nasim Sabbah UWA asgari@ee.uwa.edu.au Asgari Asghar UWA asgari@ee.uwa.edu.au TM4 Barjaktarevic John Paul UQ jpb@physics.uq.edu.au TP20 Bartos Igor UNSW ibartos@phys.unsw.edu.au TP1 Baxter Geoff CSIRO geoff.baxter@csiro.au WP9 Bertram Bill ANSTO wkb@ansto.gov.au WP1 Bigelow Roberta Monash roberta.bigelow@spme.monash.edu.au Bowles Cameron ANU cameron.bowles@anu.edu.au TP19 Broekman Leonard Latrobe L.Broekman@latrobe.edu.au WP28, WP29 Bryant Gary RMIT gary.bryant@rmit.edu.au WP2, WP7 Cahen David Weizmann Inst Israel david.cahen@weizmann.ac.il WM2 Cashion John Paul Monash John.Cashion@spme.monash.edu.au WP27, WP41, TM6, TA2, TP21 Chai Roger CSIRO roger.chai@csiro.au Chen Cheng ANU chc107@rsphysse.anu.edu.au TP19 Cho Sam QUT sycho@physics.uq.edu.au TP2, TP7 Cimmino Alberto Melbourne a.cimmino@physics.unimelb.edu.au TP3 Collocott Stephen CSIRO stephen collocott@csiro.au Court Nadia UNSW ncourt@phys.unsw.edu.au TP4 Crew David UWA dcrew@physics.uwa.edu.au TA3, TA5 Daivis Peter RMIT peter.daivis@rmit.edu.au TM8 Dieing Thomas Latrobe t.dieing@ee.latrobe.edu.au TP5 Downes James VUW, NZ james.downes@vuw.ac.nz TA1 Dunbar Alan Canterbury, NZ alan.dunbar@canterbury.ac.nz WM3 Dunlop John CSIRO john.dunlop@csiro.au Edge Vernon UNSW, ADFA v.edge@adfa.edu.au WP18, WP20, WP21, WP22, WP25 Eggleton Ben Sydney U egg@Physics.usyd.edu.au TM1, TP38, TP40 Fehske Holger Uni Greifswald, DE fehske@physik.uni-greifswald.de TP24, FM6 Finlayson Trevor Monash Trevor.Finlayson@spme.monash.edu.auWP3, WP34, WP39, WP42, TP35 Fleming Robert Monash Robert.Fleming@spme.monash.edu.au Fletcher Neville ANU neville.fletcher@anu.edu.au Foley Cathy CSIRO Cathy.Foley@csiro.au WA1 Ford Mike UTS mike.ford@uts.edu.au WM4 Gassull Daniel Melbourne dgassull@ph.unimelb.edu.au TP3 Glasscock Julie CSIRO julie.glasscock@csiro.au TM9, TP38, TP40 Goossens Darren ANU goossens@rsc.anu.edu.au WM6, WA3, WP6, WP17 Gorham Nicole UWA gorham@physics.uwa.edu.au TA4 Greaves Tam Monash tamar.greaves@spme.monash.edu.au TA2 Greentree Andy UNSW a.d.greentree@unsw.edu.au TP10, TP11 Grillet Christian Sydney U grillet@Physics.usyd.edu.au TM2, TP38, TP40 Grimm Douglas UNSW, ADFA dbg@ph.adfa.edu.au WP18, WP22 Gwan Paul CSIRO paul.gwan@csiro.au WP33 Hagen Mark ANSTO mhz@ansto.gov.au WP4, WP5 Hallam Toby UNSW toby@phys.unsw.edu.au FM1, TP6 Hamer Chris UNSW cjh@phys.unsw.edu.au TP25 Hancock Yvette Monash Yvette.Hancock@spme.monash.edu.au TP26 Harker Stephen Monash Stephen.Harker@spme.monash.edu.au WP6, TM6, TP21 Hearne Sean Melbourne smh@physics.unimelb.edu.au TP7 Hutchison Wayne UNSW, ADFA w.hutchison@adfa.edu.au WP20, WP25, TP8 Ito Naoki Monash Naoki.Ito@spme.monash.edu.au WP19 Jakovidis Greg Monash Greg.Jakovidis@sci.monash.edu.au WP15, FM5 Jackson Ian ANU Ian.Jackson@anu.edu.au WP35 Jamieson Ian Monash Ian.Jamieson@spme.monash.edu.au TP7, FM5 Koo Annette VUW, NZ a.koo@irl.cri.nz FM4, TP28 Lam Simon CSIRO simon.lam@csiro.au WA1, WP36 Lamb Belinda NYST belinda.lamb@nyst.edu.au Lang Sidney Ben Gurion U lang@bgumail.bgu.ac.il TM5 Lee Sueping UOW sueping@uow.edu.au TP9 Lenné Thomas RMIT Thomas.lenne@rmit.edu.au WP7 Lewis Roger UOW roger@uow.edu.au WP21, TP9 Lundin Urban UQ ludin@physics.uq.edu.au TP2, FM8 Luscher Andreas UNSW andreas.luescher@a3.epfl.ch TP27 Maaroof Abbas UTS amaaroof@uts.edu.au TP39 Madebo Mebratu Latrobe m.mebratu@latrobe.edu.au FM3 Marshall Craig Scitek Aust Exhibitor McCamey Dane UNSW dane.mccamey@unsw.edu.au TP10 Mezei Ferenc Hahn-Meitner Inst, DE mezei@wanadoo.fr WM5 Miller David Sydney U davmille@arts.usyd.edu.au TP30 Mitic Mladen UNSW m_mitic2003@yahoo.com TP11 Mukhamedjanov Timur UNSW tmukham@phys.unsw.edu.au TP32 Muller Karl CSIRO karl.muller@csiro.au WM1, WP9 Nakamura Yuichi Tokyo Uni, Japan yuichi@iis.u-tokyo.ac.jp WA6 Norris Ray ATNF Ray.Norris@csiro.au Oitmaa Jaan UNSW j.oitmaa@unsw.edu.au WA4, TP22, TP23 Pardoe Heath UWA hpardoe@physics.uwa.edu.au WA2 Paulmier Thierry QUT t.paulmier@qut.edu.au WP37 Price Don CSIRO don.price@csiro.au Ponomarenko Olena Newcastle olena@engmail.newcastle.edu.au WP10, WP11 Rabeau James Melbourne jrabeau@physics.unimelb.edu.au WP12 Read Marlene UNSW m.read@unsw.edu.au TP31 Riley John Paul Latrobe j.riley@latrobe.edu.au WP28, WP29, WP39, TP12, TP13, FM3 Roberts Mark CSIRO mark.roberts@csiro.au Robinson Robert ANSTO rro@ansto.gov.au WA3 Rosse Meg Latrobe M.Rosse@latrobe.edu.au Ruck Benjamin VUW, NZ avekony@paradise.net.nz FM4, TP28 Russo Salvy RMIT salvy.russo@rmit.edu.au FM9 Rybachuk Maksym QUT m.rybachuk@qut.edu.au WP26 Sabine Terry UTS terencesabine@hotmail.com WP38 Savvides Nick CSIRO Nick.Savvides@csiro.au TP15, TP38, TP40 Shadrivov Ilya ANU ivs124@rsphysse.anu.edu.au TM3 Schmid Siggi Sydney U siegbert@chem.usyd.edu.au WM7 Sirker Jesko UNSW sirker@phys.unsw.edu.au WM8 Sloggett Clare UNSW clares@phys.unsw.edu.au TP14 Smith Andrew Monash Andrew.Smith@spme.monash.edu.au WP27, WP39, TP33 Smith Geoff UTS g.smith@uts.edu.au TP39 Smith Justin Monash Justin.Smith@spme.monash.edu.au TP35 Simmons Michelle UNSW Michelle.Simmons@unsw.edu.au TP6, FM1 Soh Martin UWA msoh@ee.uwa.edu.au TP15 Sosa Pintos Andreas UWS andreas.sosapintos@csiro.au WP33 Soule de Bas Benjamin UTS benjamin.souledebas@uts.edu.au WM4 Spiers Kathryn Monash kathryn.spiers@spme.monash.edu.au TM6, TP21 Stamps Robert UWA stamps@lps.u-psud.fr WP8, WP23, TA3, TA4, TA5 Stanton Bill Stanton Scientific Exhibitor Stachurski Zbigniew ANU zbigniew.stachurski@anu.edu.au WP24 Stewart Andrew ANU andrew.stewart@anu.edu.au WP40 Stewart Glen UNSW, ADFA g.stewart@adfa.edu.au WP20, WP21, WP25 Studer Andrew ANSTO ajs@ansto.gov.au WP18, WP21, WP25 Sushkov Oleg UNSW sushkov@phys.unsw.edu.au TP14, TP32, TP34 Suwuntanasarn Nakorn UNSW, ADFA n.suwantanasarn@student.adfa.edu.au Ta'eed Vahid Sydney U vahid@Physics.usyd.edu.au TP40 Tadich Anton Latrobe a.tadich@latrobe.edu.au WP28, WP29 Tansley Trevor Macquarie Trevor.tansley@mq.edu.au TP16 Tempelaars Dave UNSW, ADFA d.tempelaars@student.adfa.edu.au WP8 Tilbrook David CSIRO david.tilbrook@csiro.au WA1 Trodahl Joe VUW, NZ Joe.Trodahl@vuw.ac.nz FM4, FM7, TP28 Troup Gordon Monash gordon.troup@spme.monash.edu.au WP30, WP31, WP32 Usher Brian Latrobe B.Usher@latrobe.edu.au TP5, FM3 Vance Lou ANSTO erv@ansto.gov.au WP34, WP41 Von Brasch Alexander UNSW alexvb@phys.unsw.edu.au WA4 Wang Jianli UNSW, ADFA jlw@ph.adfa.edu.au WP22 Wang Qian UOW qian@uow.edu.au TP9 Warnes Bill Monash bill.warnes@spme.monash.edu.au Weisse Alexander UNSW aweisse@phys.unsw.edu.au TP24, TP36, FM6 White Guy CSIRO guy.white@csiro.au Woodward Robert UWA woodward@physics.uwa.edu.au TA4, TA5 Wu XD Monash Xiaodong.wu@spme.monash.edu.au WP3, WP42 Xiong Xiangyuan Monash xiangyuan.xiong@spme.monash.edu.au WP43 Xu David UTS xiaoda.xu@uts.edu.au WP13 Yang Wenrong CSIRO wenrong.yang@csiro.au WP14 Yu Dehong ANSTO dyu@ansto.gov.au WM9, WP6 Yu Rotha Monash rotha.yu@spme.monash.edu.au TP37 Zalich Michael UWA mzalich@cyllene.uwa.edu.au TM7 Zhu DeMing Monash Deming.Zhu@spme.monash.edu.au WP15