X-ray magnetic circular dichroism study of an orbital ordered state in the spinel-type vanadium oxide AV2O4 (A = Mn, Fe)

Spinel-type vanadium oxides FeV2O4 and MnV2O4 are considered to exhibit different types of V3+ orbital order from each other. In order to tackle this issue, the temperature dependence of x-ray absorption spectrum (XAS) and x-ray magnetic circular dichroism (XMCD) spectrum are investigated in both spinel compounds. The application of the sum rule to the obtained V edge XMCD spectra and the comparison with crystal-field multiplet calculations suggest a real orbital ordered state with quenched orbital angular momenta in both FeV2O4 and MnV2O4. A dissimilarity in XAS spectra between these compounds would originate from a quantitative difference of trigonal distortion.