Synchrotron x-ray-diffraction study of orbital ordering YVO₃

Synchrotron x-ray-diffraction experiments have been carried out in a perovskite-type vanadium oxide YVO₃ to elucidate orbital ordering of the system. The change from C- to G-type orbital ordering at the lower magnetic transition temperature was strongly suggested. The long-range orbital ordering appears also in the high-temperature paramagnetic phase. Azimuthal-angle dependence of orbital superlattice reflections indicates that for both orbital-ordering phases the orbital occupation is approximately the d_xy/¹d_yz/¹ and d_xy/¹d_zx/¹ configuration in two sublattices, respectively. These results are in good agreement with a theoretical prediction.