Theory of the Single Ion Magnetocrystalline Anisotropy of 3d Ions

Abstract

Abstract Methods for calculating the single ion magnetocrystalline anisotropy of 3d ions in the crystal field with threefold axis or higher symmetry and lower symmetry are given. Using these methods, the contributions of Fe 3+ ions at all the five crystal sites of Ba‐ferrite (BaM) to the magnetocrystalline anisotropy constants and their temperature dependence are calculated. Also calculated is the single ion anisotropy of the Co 2+ ion substituting the Fe 3+ ion at the 12k site. The results agree well with experiments.