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.
Keywords
Cite
@article{arxiv.1009.0429,
title = {Spin and Orbital Order of the Vanadium Spinel MgV2O4},
author = {Elisa M. Wheeler and Bella Lake and A. T. M. Nazmul Islam and Manfred Reehuis and Paul Steffens and Tatiana Guidi and Adrian H. Hill},
journal= {arXiv preprint arXiv:1009.0429},
year = {2010}
}