On the conditions of ferromagnetism by the band model: II

Abstract

A new method is proposed for examining the dependence on the magnetization of the free energy for electrons at finite temperatures in the band model. By this method the conditions for ferromagnetism for electrons in metals with an arbitrarily complicated density of states are discussed. It is pointed out that a first-order transition in the magnetization may occur both at low temperature and at high temperatures in a case where the Fermi level is in the neighbourhood of a minimum in the density of states curve. The comparison between the theory and several experimental results which show a first-order transition, for example MnAs, is discussed.