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TT: Tiefe Temperaturen

TT 16: Posters Correlated Electrons, Measuring Devices, Cryotechnique

TT 16.52: Poster

Samstag, 5. März 2005, 11:00–16:30, Poster TU C

Comparison of X-ray absorption spectra of V₂O₃ at the O K edge to full multiple scattering calculations — •P. Pfalzer, J.-P. Urbach, J. Moosburger-Will, A. Nateprov, jr., M. Klemm und S. Horn — Universität Augsburg, Lehrstuhl für Experimentalphysik II, Universitätsstr. 1, 86135 Augsburg

X-ray absorption measurements at the O K edge are compared to full multiple scattering (FMS) calculations for the paramagnetic metallic, paramagnetic insulating and antiferromagnetic insulating phases of V₂O₃. The description of angular dependencies in experimentally recorded X-ray absorption near edge structure (XANES), even over an extended energy range, is possible with these calculations for the first time. Additionally, comparison of the experimental XANES with the FMS calculations corroborates the findings from EXAFS measurements, that V₂O₃ does not have local structure with trigonal symmetry in the metallic phase at room temperature. The observed large anisotropy of the XANES in the insulating phases is shown to be a direct consequence of the distorted physical structure. The calculations also suggest that the low energy part of the O 1s absorption edge is not rigorously split into a “t_2g”- and an “e_g”-part as suggested from bandstructure calculations.