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TT: Fachverband Tiefe Temperaturen

TT 44: Poster Session Correlated Electrons

TT 44.41: Poster

Donnerstag, 17. März 2011, 10:00–13:00, P1

On the development of orbital order domains across the Verwey transition in magnetite — •M. Döhler¹, C. F. Chang¹, M. Buchholz¹, C. Trabant^1,2, T. Kachel², N. Pontius², M. Beye^2,3, F. Sorgenfrei⁴, W. Schlotter³, S. de Jong³, R. Kukreja³, B. Bräuer³, S. Hossain³, C. Back³, A. Scherz³, D. Zhu³, J. Turner³, W.-S. Lee³, Y.-D. Chuang³, O. Krupin³, P. Vogt¹, W. Wurth⁴, A. Föhlisch², J. B. Goedkoop⁵, H. A. Dürr³, and C. Schüßler-Langeheine^2,1 — ¹II. Physikalisches Institut, Universität zu Köln — ²Helmholtz-Zentrum Berlin — ³SLAC RSXS collaboration, USA — ⁴Universität Hamburg and CFEL — ⁵Van der Waals-Zeeman Institute, Universiteit van Amsterdam

The Verwey transition in magnetite (Fe₃O₄) involves a symmetry reduction from cubic to monoclinic and the formation of orbital order at low temperatures. In the low-temperature phase orbital-order domains form. We used resonant soft x-ray diffraction to study how this orbital-order domain pattern changes in the vicinity of the Verwey transition. We found that very close to the transition the domains become mobile, which we assign to fluctuations between the high- and the low-temperature phase. In order to understand how the domain pattern changes when the transition is driven by a fs-infrared-laser pulse, we carried out a time-resolved resonant soft x-ray diffraction experiment at the LCLS. We find that the IR-pulse affects mainly the peak intensity and much less the correlation length of orbital order. Supported by the DFG through SFB 608 and by the BMBF project 05K10PK2.