First-Principles Study on the Magnetic Anisotropy in Multiferroic PbVO3 and BiCoO3

Magnetic anisotropy energies (MAE) of multiferroic PbVO3 and BiCoO3 are evaluated from first-principles density functional calculations. Even though both oxides have similar crystal and electronic structures, calculated easy axes of spin are different: [110] in PbVO3 and [001] in BiCoO3. To explain the difference, the origin of MAE is discussed with a perturbation theory by taking into account of the electronic structure obtained by the first-principles calculations