Correlation of magnetocrystalline anisotropy of Fe0.5Pd0.5alloy with chemical order

We study the magnetocrystalline anisotropy of Fe 0.5 Pd 0.5 alloy using the first-principles spin-polarized relativistic Korringa-Kohn-Rostoker coherent-potential approximation. We investigate the effect of long-ranged chemical order on the magnitude as well as the direction of easy magnetization. We find that in this alloy, the chemical order enhances the magnitude of the magnetocrystalline anisotropy energy as well as altering the easy axis. In particular, for the L 1 0 ordered alloy the easy axis is perpendicular to the alternating layers of Fe and Pd with quite large magnetocrystalline anisotropy energy 124 µeV. These observations are in very good agreement with experiments. We also find that it is the electronic structure in the vicinity of the Fermi surface that is responsible for this effect.