Magnetovolume Effects of Itinerant Electron Ferromagnets. II. Pressure Dependence of Spontaneous Magnetization and Forced- and Spontaneous-Volume Magnetostriction at 0°K

Abstract

Pressure dependence of spontaneous magnetization and forced- and spontaneous-volume magnetostriction in itinerant electron ferromagnets at 0°K are formulated. Dependence on atomic volume of the band width and of the molecular field coefficient are taken into account. It is shown that the spontaneous volume magnetostriction ω s , must be negative when the forced one ω H , is negative while the former may be positive or negative when the latter is positive. It is easily understood why ω H is positive or whereas ω s is negative in Ni, Fe and some Ni-Fe alloys. If Kanamori's theory considering the correlation between electrons is applied to the molecular field coefficient, then ω H is positive at 0°K. So far has been found no metallic ferromagnets with negative ω H at low temperature, with an exception of dilute Fe-alloys. Diagrammatic representation to relate the density of states to forced- and spontaneous-volume magnetostriction is given.