ORIGIN OF ORBITAL MAGNETIZATION AND MAGNETOCRYSTALLINE ANISOTROPY IN TX ORDERED ALLOYS (WHERE T=FE,CO AND X=PD,PT)

We present a method to calculate the magnetic anisotropy parameters wh ich is based on a perturbative treatment of the spin-orbit interaction and a Green's function technique in real space. it allows us to inter pret the magnetocrystalline anisotropy energy (MAE) in terms of intera tomic interactions in the crystal. The method is applied to analyze or bital magnetism and MAE in TX ordered alloys (T=Fe,Co and X=Pd,Pt). Th e convergence of the orbital moments and MAE in real space and its rel ation to the problems of Brillouin-zone integration and of oscillatory behavior of MAE as a function of band filling are discussed. A compar ison with results obtained by other methods is also given.