Spin and Orbital Order of the Vanadium Spinel MgV2O4

Abstract

We present a unique study of the frustrated spinel MgV2O4 which possesses highly coupled spin, lattice and orbital degrees of freedom. Using large single-crystal and powder samples, we find a distortion from spinel at room temperature (space group F-43m) which allows for a greater trigonal distortion of the VO6 octahedra and a low temperature space group (I-4m2) that maintains the mirror plane symmetry. The magnetic structure that develops below 42 K consists of antiferromagnetic chains with a strongly reduced moment while inelastic neutron scattering reveals one-dimensional behavior and a single band of excitations. The implications of these results are discussed in terms of various orbital ordering scenarios. We conclude that although spin-orbit coupling must be significant to maintain the mirror plane symmetry, the trigonal distortion is large enough to mix the 3d levels leading to a wave function of mixed real and complex orbitals.

References in corpus (5)

• Structural, orbital, and magnetic order in vanadium spinels
• Magnetic transition and orbital degrees of freedom in vanadium spinels
• Orbital order in ZnV${}_2$O${}_4$
• Orbital and magnetic transitions in geometrically-frustrated vanadium spinels -- Monte Carlo study of an effective spin-orbital-lattice coupled model --
• Homopolar bond formation in ZnV${}_2$O${}_4$ close to a metal-insulator transition

Cited by in corpus (1)

• CdV2O4: A rare example of a collinear multiferroic spinel