Spinel MnV2O4 exhibits orbital ordering at T c=57 K accompanied by a structural phase transition from cubic to tetragonal and ferrimagnetic ordering. We measured the temperature dependence of the optical reflectivity spectra on the cleaved surface of a MnV 2O4 single crystal with controlled twin structures below Tc. We found that there are two peaks at 1.6 and 2.3 eV, corresponding to the Mott excitations, in the optical conductivity spectra obtained by the Kramers-Kronig transformation of the reflectivity, and that the two peaks exhibit a similar anisotropic change below Tc. Furthermore, we found that these two peaks exhibit a different temperature dependence above Tc. We analyzed these results by a model in which the multiplet structures of the d state for the Mott excitation are fully taken into account, and discussed the occupation of the triply degenerate t2g orbitals both below and above Tc.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2013 Feb 19|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics