Schmitz, D.; Schmitz-Antoniak, C.; Radu, F.; Ryll, H.; Luo, C.; Bhandary, S.; Biermann, S.; Siemensmeyer, K.; Wende, H.; Ivanov, S.; Eriksson, O.: Soft X-Ray Magnetic Circular Dichroism of Vanadium in the Metal-Insulator Two-Phase Region of Paramagnetic V2O3 Doped with 1.1\% Chromium. Physica Status Solidi B 257 (2020), p. 1900456/1-7
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V2O3 doped with 1.1% Cr is investigated at its isostructural correlation-driven metal-insulator transition near room temperature in its paramagnetic state with X-ray magnetic circular dichroism (XMCD) spectroscopy in external magnetic fields. A relative XMCD amplitude of about two permille is observed at the L2,3 absorption edges of vanadium as expected for magnetic moment per mass values of the order of 1 J/T/kg from magnetometry and the literature. Across the metal-insulator transition the vanadium XMCD spectral shape significantly changes. According to atomic multiplet simulations, these changes are due to a changing orbital occupation indicating a changing phase composition. According to estimates used in this study, the dipole moment of the spin density distribution 7Tz in the bulk increases such that the effective vanadium spin moment increases by a few percent with temperature in the two-phase region. Thereby it partially compensates for the decrease of the relative XMCD amplitude due to a decreasing alignment of the paramagnetic moments. After a few minor temperature cycles the sample is in a two-phase state in which the XMCD and X-ray linear dichroism spectra hardly depend on the temperature and the specific electrical resistance is intermediate showing only a weak sign of the metal-insulator transition.