First principles study on the magnetocrystalline anisotropy of Fe--Ga magnetostrictive alloys

This paper investigates the electronic structure andmagnetocrystalline anisotropy of Fe--Ga magnetostrictive material bymeans of the full potential-linearized augmented plane-wave methodwithin the generalized gradient approximation. The 3d-orbitsplitting of Fe atoms in D0₃, B2-like and L1₂ crystallinestructures of Fe--Ga is calculated with consideration of the crystalfield as well as the spin--orbit coupling effect. Because of thefrozen orbital angular momenta of the 3d-orbit for Fe atoms in Fe--Gamagnetostrictive alloys and the spin--orbit coupling, thedistribution of the electron cloud is not isotropic, which leads tothe anisotropy of exchange interaction between the different atoms.A method on estimating the magnetocrystalline anisotropy of Fe--Gaalloys by means of calculating orbit-projected density of states forFe atoms is performed. The anisotropic distribution of the electroncloud of Fe atoms in these three crystalline structures of Fe--Ga isstudied based on the above method showing the highest magneticanisotropy for B2-like structure. This qualitative method comescloser to physical reality with a vivid physical view, which canevaluate the anisotropy of electron cloud for 3d transition atomsdirectly. The calculated results are in good agreement with both theprevious theoretical computation and the tested value on themagnetic anisotropy constant, which confirms that the electron cloudanisotropy of Fe atoms could well characterize themagnetocrystalline anisotropy of Fe--Ga magnetostrictive material.