Magnetic anisotropy of ordered and disordered FePd thin films - art. no. 184408

The magnetic anisotropy energy of Fe films, FePd surface alloys, as well as ordered and interdiffused (FenPdm)(r) superstructures on Pd(100) and Pd(11 1) are evaluated using a fully relativistic spin-polarized screened Koninga -Kohn-Rostoker method. It is found that only an ordered Fe1Pd1 superstructu re grown on Pd(100) exhibits perpendicular magnetism, while for all other s ystems under investigation the magnetization is oriented in plane. By using the inhomogeneous coherent potential approximation ibr layered systems, th e effect of ordering into (repeated) superstructures can be described ab in itio. It is found that already small amounts of interdiffusion can be decis ive for the actual value of the magnetic-anisotropy energy. The present the oretical results as compared to experiments indicate that changes in the ma gnetic-anisotropy energy related to chemical order might arise either throu gh changes in the crystallographic structure or through changes in the elec tronic structure and Pd-induced spin-orbit coupling.