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DF: Fachverband Dielektrische Festkörper
DF 22: Poster II
DF 22.66: Poster
Friday, March 15, 2013, 10:30–13:30, Poster D
Determination of the magnetic depth profile of high-quality Fe3O4/ZnO heterostructures by polarized neutron reflectometry — •Michael Zapf1, Ozan Kirilmaz1, Sebastian Brück1, Nina-Juliane Steinke2, Nadezda Tarakina3, Martin Kamp3, Eberhard Goering4, Michael Sing1, and Ralph Claessen1 — 1Physikalisches Institut, Universität Würzburg, Germany — 2Rutherford Appleton Laboratory, Chilton, UK — 3Technische Physik, Universität Würzburg, Germany — 4Max Planck Institute for Intelligent Systems, Stuttgart, Germany
Magnetite (Fe3O4) is one of the most promising materials for use as a spin injector into a semiconducting host. We demonstrate epitaxial growth of Fe3O4 films on the polar surfaces of ZnO single crystals. X-ray photoelectron spectroscopy evidences that the MBE-grown samples are phase-pure and nearly stoichiometric. The growth mechanism, the surface and film structure, the chemical profile and magnetic properties have been investigated in our previous publications.
To gain detailed information on the magnetic profile, polarized neutron reflectometry measurements were performed. Values for film thickness, roughness and magnetic moment were obtained from the reflectivity curves and checked against X-ray reflectometry, transmission electron microscopy and magnetometry data. A several nanometer thick region of reduced magnetization in the strained Fe3O4 layers near the heterointerface could be resolved. Thereby the efficiency of spininjection into ZnO could be strongly affected.