Dresden 2006 – scientific programme

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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Poster Session

TT 25.86: Poster

Wednesday, March 29, 2006, 14:30–18:30, P1

Electronic structure of Fe₃O₄/MgO — •C. F. Chang¹, J. Schlappa¹, C. Schüßler-Langeheine¹, H. Ott¹, Z. Hu¹, E. Schierle², E. Weschke², G. Kaindl², A. Tanaka³, and L. H. Tjeng¹ — ¹II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany — ²Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany — ³Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530, Japan

Magnetite thin films grown on flat and stepped MgO have been studied using transport and resonant soft x-ray diffraction measurements. Down to a thickness of 38 nm a clear 1st order Verwey transition is observed. Resonant soft x-ray diffraction at the Fe L_2,3 and O-K resonances was used to study the electronic structure in the low-temperature phase. The broadening of the diffraction peaks along the surface normal in thin films allowed us not only to study the (001/2) superstructure peak at both resonances, but also the tail of the (001) diffraction peak, which cannot be reached at the Fe-L_2,3 resonance for bulk samples. The electronic origin of both peaks turns out to be clearly different. Possible models for the ordered phase will be discussed.