Alloy-analogy treatment of valence transition in rare-earth systems

Abstract

A system of rare-earth atoms with mixed valency is viewed as an alloy A1-nBn, where n denotes the probability of finding the rare-earth atom in the state with valence three and (1-n) is the probability of finding the rare-earth atom in the state with valence two. The coherent potential approximation (CPA) used in alloy theory is then applied to determine the d and f electron configuration in such systems. Thus, the various properties of systems with mixed valency can be determined. The theory also includes local environment effects. An explanation is offered for various properties observed for rare-earth compounds.