Browsing by Author "Goering, E"

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    Element-specific depth profile of magnetism and stoichiometry at the La0.67Sr0.33MnO3/BiFeO3 interface
    (American Physical Society, 2014-07-11) Bertinshaw, J; Brück, S; Lott, D; Fritzsche, H; Khaydukov, Y; Soltwedel, O; Keller, T; Goering, E; Audehm, P; Cortie, DL; Hutchison, WD; Ramasse, QM; Arredondo, M; Maran, R; Nagarajan, V; Klose, F; Ulrich, C
    Depth-sensitive magnetic, structural, and chemical characterization is important in the understanding and optimization of physical phenomena emerging at the interfaces of transition metal oxide heterostructures. In a simultaneous approach we have used polarized neutron and resonant x-ray reflectometry to determine the magnetic profile across atomically sharp interfaces of ferromagnetic La0.67Sr0.33MnO3/multiferroic BiFeO3 bilayers with subnanometer resolution. In particular, the x-ray resonant magnetic reflectivity measurements at the Fe and Mn resonance edges allowed us to determine the element-specific depth profile of the ferromagnetic moments in both the La0.67Sr0.33MnO3 and BiFeO3 layers. Our measurements indicate a magnetically diluted interface layer within the La0.67Sr0.33MnO3 layer, in contrast to previous observations on inversely deposited layers [P. Yu et al., Phys. Rev. Lett. 105, 027201 (2010)]. Additional resonant x-ray reflection measurements indicate a region of altered Mn and O content at the interface, with a thickness matching that of the magnetic diluted layer, as the origin of the reduction of the magnetic moment.© 2014, American Physical Society.
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    Local magnetic structure at the Fe3O4/ZnO interface
    (Australian Institute of Physics, 2012-02-01) Brück, S; Paul, M; Tian, H; Müller, A; Fauth, K; Goering, E; Verbeeck, J; Van Tendeloo, G; Claessen, R
    Magnetite, Fe3O4, is a half-metal with 100% spin polarization of the minority band at the Fermi level. This together with its good conductivity match to standard semiconductors makes it a promising candidate for polarized spin injection into semiconductor materials such as Si, GaAs, or ZnO [1]. An important aspect for such applications is the magnetism directly at the interface between Fe3O4 and the semiconductor. Soft x-ray resonant magnetic reflectometry is a technique which is capable of providing structural and magnetic depth profiles with 0.1nm resolution. We present a detailed XRMR and electron energy loss spectroscopy (STEM/EELS) study of an epitaxial Fe3O4 thin film grown directly on a semiconducting ZnO substrate [2]. Consistent chemical profiles at the interface between ZnO and Fe3O4 are found from XRMR and EELS. The magnetic depth profile of tetragonal Fe3+ and octahedral Fe2+ ions in Fe3O4 is derived with monolayer resolution and reveals a change in the Fe stoichiometry directly at the interface.
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    Magnetic proximity effect in YBa2Cu3O7/La2/3Ca1/3MnO3 and YBa2Cu3O7/LaMnO3+delta superlattices
    (Amnerican Physical Society, 2012-05-07) Satapathy, DK; Uribe-Laverde, MA; Marozau, I; Malik, VK; Das, S; Wagner, T; Marcelot, C; Stahn, J; Bruck, S; Ruhm, A; Macke, S; Tietze, T; Goering, E; Frano, A; Kim, JH; Wu, M; Benckiser, E; Keimer, B; Devishvili, A; Toperverg, BP; Merz, M; Nagel, P; Schuppler, S; Bernhard, C
    Using neutron reflectometry and resonant x-ray techniques we studied the magnetic proximity effect (MPE) in superlattices composed of superconducting YBa(2)Cu(3)O(7) and ferromagnetic-metallic La(0.67)Ca(0.33)MnO(3) or ferromagnetic-insulating LaMnO(3+delta). We find that the MPE strongly depends on the electronic state of the manganite layers, being pronounced for the ferromagnetic-metallic La(0.67)Ca(0.33)MnO(3) and almost absent for ferromagnetic-insulating LaMnO(3+delta). We also detail the change of the magnetic depth profile due to the MPE and provide evidence for its intrinsic nature. © 2012, American Physical Society.