On the Calculation of the Magnetic Structure of Surfaces, Near-Surface Layers, and Interfaces of 3d Metals

A microscopic approach to the calculation of the distribution of magnetic moments in the vicinity of surfaces, interfaces, and other spatially inhomogeneous 3d metal systems is proposed in the framework of model Hamiltonians for itinerant electrons. The method of Green's functions in the configuration space is used. The equations for Green's functions are solved by the recursion method. The poles of the Green's functions of d electrons are numerically determined, and then, analytical expressions are derived for the density of states and the occupation numbers of electronic states. The magnetic moments in the vicinity of surfaces and interfaces with different orientations relative to crystallographic axes are calculated for ferromagnetic iron and antiferromagnetic chromium. The dependences of the magnitude of the magnetization on the distance to the surface for both metals proved to be very similar to each other, even though the densities of states and the types of their magnetic ordering are different. Compared to massive samples, the magnetic moments at Fe/Cr interfaces increase for chromium and decrease for iron, and the magnetization profile depends on the interface orientation. The results of the calculation make it possible to explain the experimental Mossbauer data for Cr/Sn and Fe/Cr/Sn multilayer systems.