Exploring the magnetic transitions in an Inverse Vanadium Spinal oxide

The spinel vanadates, AV2O4, are captivating, complex magnets, in particular in studying the role of orbital degrees of freedom in frustrated antiferromagnets. We propose to investigate the much less studied inverse spinel Co2VO4, where the B-site has mixed occupancy by two distinct magnetic ions, V4+ and low-spin Co2+. Our preliminary results show three distinct magnetic-phase transitions, among which a spontaneous irreversible magnetization reversal transition at 75 K. Contrary to the other two magnetic transitions at 165 and 145 K, this magnetization reversal is not evident in zero-field neutron powder diffraction. To fully understand the nature of the magnetic transitions at 165, 145, and especially at 75 K, we propose to carry out systematic zero-field µSR experiments as a function of temperature and longitudinal field µSR experiments, above and below all transition temperatures.