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    Polarized neutron reflectometry of epitaxial Fe[0.25 + x] Pt[0.75 – x] layers.
    (Institute of Electrical and Electronics Engineers (IEEE), 2018-04-27) Mankey, GJ; Causer, GL; Cortie, DL; Wang, X; Zhu, H; Lonescu, M; Klose, F
    Epitaxial Fe[0.25 + x]Pt[0.75 - x] layers can be either antiferromagnetic (AF) or ferromagnetic (FM) depending on the degree of chemical ordering controlled by the deposition temperature. Our neutron diffraction studies were the first to study AF phase transitions in these thin films [1] and we have also shown using PNR that a mixed AF-FM film is exchange biased with itself [2]. In AF-FM exchange-biased superlattices with a modulated chemical order parameter, PNR shows the magnetization can be modulated through the film thickness with no composition modulations [3]. Our recent results reveal that He+ ion bombardment and annealing can be applied toward controlling magnetic phases in epitaxial Fe [0.25] Pt [0.75] layers [4]. © Copyright 2024 IEEE - All rights reserved, including rights for text and data mining and training of artificial intelligence and similar technologies.
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    Electron beam welding of stainless steels
    (International Institute of Welding, 1976-08-23) Chrimes, NWD; Gardner, RV
    A review is given of some of the principal problems encountered in the operation of a 30kV 500 mA electron beam unit installed at Lucas Heights in 1970. The principal welding parameters for the successful operation of a unit of this type are discussed, with particular emphasis on gun to work distance and vacua, and their effect on the weld properties.
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    Parameters controlling emission of terahertz frequency electromagnetic radiation from InAs and GaAs: an ensemble Monte Carlo simulation study
    (The Electrochemical Society, 2013-03-15) Cortie, DL; Lewis, RA
    The generation, manipulation and detection of terahertz-frequency electromagnetic radiation are topics of great current theoretical and experimental interest. In particular, the coherent generation and detection of ultrashort pulses of terahertz radiation has opened up the field of terahertz time-domain spectroscopy, which permits the simultaneous measurement of amplitude and phase of the terahertz electric field. In this paper, the emission of terahertz radiation from bare semiconductor surfaces following photoexcitation by ultrashort pulses of near-infrared radiation is studied using ensemble Monte Carlo simulations. The simulation allows us to examine separately distinct scattering mechanisms and to vary the materials parameters of bandgap, absorption coefficient, effective mass, and surface potential. The narrower-gap semiconductor InAs and the wider-gap semiconductor GaAs are given as examples in which diffusion and drift processes, respectively, dominate. We find that scattering is relatively unimportant in the case of InAs but is very important in the case of GaAs. © The Electrochemical Society
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    8Li+ β-NMR in the cubic insulator MgO
    (IOP Publishing, 2014-12-16) MacFarlane, WA; Parolin, TJ; Cortie, DL; Chow, KH; Hossain, MD; Kiefl, RF; Levy, CDP; McFadden, RML; Morris, GD; Pearson, MR; Saadaoui, H; Salman, Z; Song, Q; Wang, D
    We present extensive high magnetic field β-NMR measurements of 8Li+ implanted in single crystals of MgO. The narrow resonance, consistent with a cubic 8Li+ site, likely the tetrahedral interstitital, is used routinely as a reference for shift measurements. We show the intrinsic linewidth is on the order of 200 Hz, allowing a frequency determination to an accuracy of a few Hz. We find no implantation energy dependence of the resonance within a few ppm, but there is evidence of slow spin dynamics in hole-burning measurements. The spin lattice relaxation is slow. The temperature dependence reveals interesting changes at low temperature whose origin remains uncertain. Open Access CC-BY
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    High temperature anisotropy of NdFeO3 determined using time-domain THz spectroscopy
    (Institute of Electrical and Electronics Engineers (IEEE), 2013-09) Constable, E; Horvat, J; Cortie, DL; Cheng, Z; Yuan, S; Cao, SX; Lewis, RA
    The temperature dependent anisotropic fields along two principal crystallographic axes (Ax and Az) is calculated for the canted antiferromagnet neodymium iron oxide in the temperature range 300 - 470 K. The calculation is performed using the experimentally determined temperature dispersion of two orthogonal antiferromagnetic magnons, obtained via time-domain terahertz spectroscopy. The experiment demonstrates the potential use of THz spectroscopy for characterising magnetic materials and offers a complementary technique to traditional neutron and magnetic methods. © 2013 IEEE.