Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Tiefe Temperaturen
TT 13: Correlated Electrons: Metal Insulator Transition - Part 1
TT 13.2: Vortrag
Dienstag, 28. März 2006, 12:00–12:15, HSZ 105
Resonant soft x-ray diffraction from magnetite thin films — •J. Schlappa1, C. F. Chang1, 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 — 2Institut für Experimentalphysik, Freie Universität Berlin — 3Department of Quantum Matter, ADSM, Hiroshima University
Magnetite (Fe3O4) undergoes a first-order transition at the Verwey temperature, TV, which is for bulk samples around 120 K. This transition is accompanied by a change of the crystal structure from the cubic to monoclinic. The electronic origin of this transition is still a matter of considerable controversy. Using resonant soft x-ray diffraction at the Fe L2,3 resonance from magnetite thin films, we studied spectroscopically the electronic origin of the (001/2) and (001) superstructure peaks, which both occur below TV. The resonances of the two superstructure peaks differ significantly and indicate that the (001) peak is caused by charge order on the octahedral B sites, while the (001/2) peak, which describes a doubling of the unit cell below TV, is caused by an order involving only Fe2+ ions on B sites.