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arXiv · 1009.0429

Spin and Orbital Order of the Vanadium Spinel MgV2O4

Elisa M. Wheeler·Bella Lake·A. T. M. Nazmul Islam·Manfred Reehuis·Paul Steffens·Tatiana Guidi·Adrian H. Hill
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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.

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Elisa M. Wheeler, Bella Lake, A. T. M. Nazmul Islam, Manfred Reehuis, Paul Steffens, Tatiana Guidi, Adrian H. Hill. 2010-09-03. Spin and Orbital Order of the Vanadium Spinel MgV2O4. https://doi.org/10.1103/physrevb.82.140406

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