We study magnetic excitations in vanadium spinel oxides A V2 O4 (A=Zn,Mg,Cd) using two models: the first one is a superexchange model for vanadium S=1 spins and the second one includes, in addition, spin-orbit coupling and crystal anisotropy. We show that the experimentally observed magnetic ordering can be obtained in both models; however, the orbital ordering is different with and without spin-orbit coupling and crystal anisotropy. We demonstrate that this difference strongly affects the spin-wave excitation spectrum above the magnetically ordered state, and argue that the neutron measurement of such dispersion is a way to distinguish between the two possible orbital orderings in A V2 O4.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Dec 28 2007|