A first-principles study of magnetostrictions of Fe3O4 and CoFe2O4

Effects of charge ordering in the octahedral sites of Fe3O4 and CoFe2O4 on their magnetostrictions are investigated using the density functional theory plus U approach. Precise description of charge ordering was found to be crucial in determining only band-gaps of Fe3O4 and CoFe2O4, but not other physical properties such as lattice constant, magnetic moment, and magnetostriction. And Co configuration in CoFe2O4 is important in determining its magnetostriction; the most stable configuration results in substantially enhanced magnetostriction (−245 ppm), compared to that (−25 ppm) of Fe3O4, in consistent with experiments.