Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 59: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth
O 59.13: Vortrag
Mittwoch, 18. März 2015, 18:00–18:15, MA 042
Surface structure of Fe3O4 under varying conditions studied by surface x-ray diffraction — •Björn Arndt1,2, Roland Bliem3, Heshmat Noei1, Oscar Gamba3, Jessica van der Hoven3, Gareth Parkinson3, and Andreas Stierle1,2 — 1Deutsches Elektron-Synchrotron (Desy), D-22607 Hamburg, Germany — 2Fachbereich Physik, Universität Hamburg, D-20355 Hamburg, Germany — 3Institute of Applied Physics, Vienna University of Technology, 1060 Vienna, Austria
Magnetite (Fe3O4) exhibits interesting material properties which makes it attractive for industrial applications as a catalyst for the water-gas shift reaction. Therefore, it is important to understand its surface structure under different conditions. The (001) surface of magnetite shows a (√2x√2)R45∘ reconstruction in UHV which gets lifted at around 450∘C as well as upon water adsorption at room temperature. To clarify the recent controversy about the atomic structure of the reconstruction and to get insight into it at different conditions, we performed a surface x-ray diffraction experiment on a natural Fe3O4 (001) single-crystal. The experiment was carried out at the ESRF ID03 beamline using an UHV-ambient pressure flow reaction chamber at 11 keV photon energy. Our data support the recently proposed surface model1 with overstochiometric oxygen concentration. Upon heating and upon water adsorption, the surface reconstruction vanishes.
[1] R. Bliem et al., submitted