Dresden 2014 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 28: Magnetic Materials I
MA 28.7: Vortrag
Mittwoch, 2. April 2014, 16:45–17:00, HSZ 04
Substrate polarization dependent magnetic and microstructural properties of high-quality Fe3O4/ZnO interfaces — •Michael Zapf1, Ozan Kirilmaz1, Sebastian Brück1, Nadezda Tarakina1, Nina-Juliane Steinke2, Eberhard Goering3, He Tian4, Jo Verbeeck4, Michael Sing1, and Ralph Claessen1 — 1Physikalisches Institut and Röntgen Research Center for Complex Materials Systems, Universität Würzburg, Germany — 2Rutherford Appleton Laboratory, Chilton, UK — 3Max Planck Institute for Intelligent Systems, Stuttgart, Germany — 4Electron Microscopy for Materials Science, University of Antwerp, Belgium
Magnetite (Fe3O4) is among the most promising materials for use as a spin injector into a semiconducting host such as, e.g. ZnO. We present a detailed study of the interface characteristics of epitaxial MBE-grown Fe3O4 films in dependence of the ZnO substrate polarization. We were able to prepare flat terraced surfaces for both Zn- and O-polar (0001) oriented substrates by ex situ annealing procedures. X-ray photoemission evidences that the films are phase-pure and stoichiometric. The growth mechanism and bulk film properties have already been investigated in previous publications. We discuss our recent data from polarized neutron and X-ray reflectometry, transmission electron microscopy TEM) and magnetometry on the influence of the chosen substrate termination on magnetism and atomic ordering at the interface of our samples. Furthermore a comprehensive TEM study shows local strain fields arising from the lattice mismatch of Fe3O4 and ZnO that lead to a modulated Fe valency at the interface.