Two inequivalent sublattices and orbital ordering in MnV2O4 studied by V-51 NMR

Abstract

We report detailed V-51 NMR spectra in a single crystal of MnV2O4. The vanadium spectrum reveals two peaks in the orbitally ordered state, which arise from different internal hyperfine fields at two different V sublattices. These internal fields evolve smoothly with externally applied field, and show no change in structure that would suggest a change of the orbital ordering. The result is consistent with the orbital ordering model recently proposed by Sarkar et al. [Phys. Rev. Lett. 102, 216405 (2009)] in which the same orbital that is a mixture of t(2g) orbitals rotates by about 45 degrees alternately within and between orbital chains in the I4(1)/a tetragonal space group.