Cluster Xα approach to magnetic interactions and phase transitions in solids

Abstract

AbstractA magnetic transition state model is developed for the description of magnetic interactions and magnetic phase transitions in solids. The model is based on the one‐electron Xα molecular orbital calculations of clusters embedded in crystal lattice and allows quantitative investigations of magnetic interactions in d and f metals, their alloys, and compounds. The energies of local spin excitations and magnetic transition temperatures are calculated for a series of systems with the electronic states localized to a different extent. The effects of covalent bonding are introduced directly into magnetic parameters calculations and appear to be of crucial importance. Magnetic properties of some disordered alloys are considered basing on the results of Xα cluster calculations performed. In the low concentration limit, the local moment existence problem is being discussed. The dependence of magnetic properties upon concentration is considered. The results of calculations allow to give the reasonable interpretation of the experimental data available and show good possibilities of the cluster model in the description of magnetic effects in solids.