Pressure induced effects on the chemical and magnetic structure of spinel MnV2O4

Abstract

The influence of external pressure (P ≤ 5 GPa) on both the structural and magnetic ordering in MnV2O4 has been investigated using neutron diffraction technique. The volume and the V-V distance decrease with pressure while the c/a ratio increases, suggesting a lowering of the distortion with pressure. Under ambient conditions this compound exhibits a structural transition (TS) from tetragonal to cubic at ∼53 K and a magnetic transition (TN) at ∼56 K. It is found that with an increase in pressure to 5 GPa, TN increases (from 56 K to 80 K), dTN/dP > 0, while TS decreases (from 53 K to 37 K). The non collinear magnetic structure in the tetragonal phase at 5 GPa and 10 K remains the same as at ambient pressure. However, the Mn and V sublattice, now exhibits distinct transition temperatures, TMnN ∼ 80 K, and TVN ∼ 60 K. The transition to the cubic phase at TS is accompanied by a collinear alignment of the Mn and V spins and a reduction in the Mn moment. The region in which the structure remains in the cubic phase with collinear magnetic structure increases with pressure from ∼3 K at ambient pressure to ∼43 K at 5 GPa pressure. © 2017 IOP Publishing Ltd.