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MM: Fachverband Metall- und Materialphysik
MM 31: Nanocharacterization
MM 31.5: Vortrag
Mittwoch, 28. März 2012, 11:15–11:30, H 1029
(contribution withdrawn) Probing intermediate valence in rare-earth compounds by X-ray excitations goes along with significant final state effects — •K. Kummer1, Yu. Kucherenko2, S. Danzenbächer2, C. Krellner3, C. Geibel3, S. L. Molodtsov4, C. Laubschat2, and D. V. Vyalikh2 — 1ESRF, Grenoble, France — 2Institut für Festkörperphysik, Technische Universität Dresden, Germany — 3Max-Planck-Institut für Chemische Physik fester Stoffe, D-01187 Dresden, Germany — 4European XFEL GmbH, Hamburg, Germany
Interaction with itinerant valence states can cause an instability of the 4f shell in rare-earth intermetallics. The resulting intermediate valence of the rare-earth ions often depends on applied pressure, temperature or chemical doping and is closely related to the magnetic and transport properties of the material. X-ray spectroscopies like 4f photoemission, X-ray absorption, or resonant inelastic X-ray scattering are very sensitive to different 4f configurations and have thus become a standard tool to study intermediate valent behavior. However, comparing results of the different X-ray spectroscopic techniques among each other and with numbers obtained with low-energy excitation methods one often finds discrepancies larger than the accuracy of each of the employed techniques. We performed theoretical simulations which reveal that final state effects lead to non-linear relations between the the weight of a 4f configuration in the ground state and its spectral weight. Valence determination from X-ray spectroscopic data requires a quantitative characterization of those final state effects which we demonstrate here at the example of intermediate valent Yb compounds.