Soft X-Ray Magnetic Circular Dichroism of Vanadium in the Metal–Insulator Two-Phase Region of Paramagnetic V₂O₃ Doped with 1.1% Chromium

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 2 permille is observed at the L_2,3 absorption edges of vanadium as expected for magnetic moment per mass values of the order of 1 J T⁻¹ kg⁻¹ 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 (Formula presented.) 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 in 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.