Magnetovolume Effects in Ferromagnetic Transition Metals

Abstract

Magnetovolume effects in ferromagnetic transition metals and alloys, such as the spon- taneous volume magnetostriction, the forced volume magnetostriction, are described by a phenomenological theory based upon a fluctuating local band picture, in which both itin- erant electron and local moment characters are taken into account. The magnetovolume effects of Fe, Ni and the Fe-Ni Invar alloy are analyzed on the basis of the proposed the- ory. It has been shown that the degree of shrinkage of local moments above the Curie temperature can be estimated from this analysis. It is concluded that local moments re- main almost unchanged in bcc Fe and, on the contrary, they shrink markedly in the Invar alloy.