Indirect Exchange Model for Ferromagnetic Metals

Abstract

The ferromagnetic properties of rare-earth metals and their alloys are discussed in terms of the indirect exchange model. It is shown by the molecular-field approximation that, in calculating the Curie temperatures of these metals, the simple theory of Fröhlich and Nabarro and Zener is applicable. The second-order energy terms calculated by Ruderman and Kittel, Kasuya, and Yosida are important in discussing the low-temperature properties. Some numerical results are obtained which are in good agreement with the experiments.