Theory of the Finite-Temperature Magnetism of NiMn —Local Environments Effect and Glass-Like Phase—

Abstract

A new theory of the magnetism at finite temperatures which takes account of the local environment effect and can describe the glass-like phase (GLP) is formulated by using the functional integral method combined with the method of the distribution function. The theory is applied to the NiMn alloy, and the local magnetic moments in various environments are calculated as the functions of the temperature, the concentration and the atomic short range order. The Curie temperature and the freezing temperature are also obtained. Anomalous behaviours such as the temperature-induced magnetization and the strongly variable magnetization with the atomic ordering in NiMn are explained for the first time by the present theory of itinerant-electron systems.