First-principles calculation of magnetoelastic coefficients and magnetostriction in the spinel ferrites CoFe2O4 and NiFe2O4

摘要

We present calculations of magnetostriction constants for the spinel ferritesCoFe2O4 and NiFe2O4 using density functional theory within the GGA+U approach.Special emphasis is devoted to the influence of different possible cationdistributions on the B site sublattice of the inverse spinel structure on thecalculated elastic and magnetoelastic constants. We show that the resultingsymmetry-lowering has only a negligible effect on the elastic constants of bothsystems as well as on the magnetoelastic response of NiFe2O4, whereas themagnetoelastic response of CoFe2O4 depends more strongly on the specific cationarrangement. In all cases our calculated magnetostriction constants are in goodagreement with available experimental data. Our work thus paves the way formore detailed first-principles studies regarding the effect of stoichiometryand cation inversion on the magnetostrictive properties of spinel ferrites.