Abstract

The Vanadium spinels AV2O4 , where A is a diamagnetic ion, provide ideal systems to study the interactions between spin, lattice and orbital degrees of freedom. The magnetic V3+ ions are antiferromagnetically coupled and sit at vertices of a network of corner sharing tetrahedra leading to three-dimensional geometrical frustration. The magnetic V3+ (S=1) has two electrons occupying the triply degenerate 3d-shell t2g orbitals. This degeneracy is only partially lifted by a tetragonal distortion at low temperatures and an orbital degree of freedom remains. ZnV2O4 is the most widely studied member of this class of compounds. Yet single crystal samples, currently not available, are needed to investigate details to distinguish between the variety of orbital ordering models predicted. I will present a study on large single crystal samples of MgV2O4 investigating the crystal and magnetic structure down to low temperatures. I will also present initial inelastic neutron scattering results and discuss the relevance to the orbital order and the magnetic models to which they approximate.