Electronic Structure Calculations for Rare Earth-Transition Metal Compounds

Abstract

The interesting magnetic properties of rare earth transition metal compounds result from the interaction between two types of atoms whose magnetic moments are of an entirely different nature. The 4f electrons, which are responsible for the magnetism of the rare earth atoms, are localized, and their electronic structure is described in terms of concepts used in atomic theory. The 3d electrons, which are responsible for the magnetism of the transition metal atoms, are itinerant: their wave functions extend over the crystal. Each electron spends only a finite time on an atom, before hopping to one of its neighbours. The magnetic properties which are related to the transition metal sublattice may be calculated using band structure theory. Using band structure theory, one can also study the crystal field interaction between the aspherical 4f shell and the charge density of the other electrons. An understanding of this interaction is essential in a theoretical treatment of the contribution of the rare earth atoms to the magnetocrystalline anisotropy.