Kademane, A.B.; Bhandari, C.; Paudyal, D.; Cottrell, S.; Das, P.; Liu, Y.; Yiu, Y.; Kumar, C.M.N.; Siemensmeyer, K.; Hoser, A.; Quintero-Castro, D.L.; Vaknin, D.; Toft-Petersen, R.: Magnetization reversal driven by electron localization-delocalization crossover in the inverse spinel Co2VO4. Physical Review B 105 (2022), p. 094408/1-9
10.1103/physrevb.105.094408
Open Access Version
Abstract:
Neutron diffraction, magnetization, and muon spin relaxation measurements, supplemented by density functional theory (DFT) calculations are employed to unravel temperature-driven magnetization reversal in inverse spinel Co2V04, All measurements show a second-order magnetic phase transition at T_C = 168 K to a collinear ferrimagnetic phase, Neutron diffraction measurements reveal two anti parallel ferromagnetic (FM) sublattices, belonging to magnetic ions on two distinct crystal lattice sites, where the relative balance between the two sublattices determine the net FM moment in the unit celL As the evolution of the ordered moment with temperature differs between the two sublattices, the net magnetic moment reaches a maximum at T_NC = 138 K and reverses its sign at T_MR = 65 K, The DFT results suggest that the underlying microscopic mechanism for the reversal is a delocalization of the unfilled 3d-shell electrons on one sublattice just below T_C, followed by a gradual localization as the temperature is lowered, This delocalized-localized crossover is supported by muon spectroscopy results, as strong 'T_1 relaxation observed below T_C indicates fluctuating intemal fields.