Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 91: Epitaxy and growth: Oxides and insulators

O 91.5: Vortrag

Donnerstag, 17. März 2011, 18:15–18:30, WIL C307

LEEM/LEED investigation of Fe3O4 thin film growth on a Pt(111) substrate — •Thomas Schmidt, Alessandro Sala, Helder Marchetto, Shamil Shaikhutdinov, and Hans-Joachim Freund — Fritz-Haber-Institut, Abt. CP, 14195 Berlin

Iron oxide, widely used as a catalyst and as a support for catalytically active systems, has been intensively studied with various techniques [1]. However, controversies in the literature regarding the surface termination and structural inhomogeneities hinder the direct linking of surface electronic and structural properties to chemical properties. Our aim is therefore a comprehensive and consistent characterization of the Fe3O4 film growth on a Pt(111) substrate by using the SMART instrument, specially designed to obtain chemical and structural information with high lateral resolution. In particular, deviating from the optimum preparation conditions [2], the oxide thin film reveals defects like a coexistence of two different stoichiometric phases (Fe3O4 and FeO), a Moiré-like patterned morphology with a mesoscopic periodicity and a predominance of one of two possible rotational domains. In addition, a subsequent annealing at 900K changes significantly the IV-LEED spectra and SPA-LEED profiles, which corresponds to different atomic termination of the magnetite surface. [1] W. Weiss and W. Ranke, Prog. Surf. Sci. 70 (2002) 1-151 [2] Z.-H. Qin, M. Lewandowski, Y.-N. Sun, S. Shaikhutdinov, and H.-J. Freund, J. Phys. Chem. C 112 (2008) 10209-10213