Forced magnetostriction in the band model of magnetism

The free energy expression of Wohlfarth for a very weak itinerant ferromagnet is amended by the addition of volume-dependent terms given by Belov. Hence the forced magnetostriction and pressure dependence of the Curie temperature are calculated. The effects depend on the volume dependence not only of the effective interaction energy but also of the fine details of the band structure. Magnetostriction measurements on ZrZn₂ by Ogawa and Waki are used to estimate that here partial differentialT_c/partial differentialP = -2·4 degK kbar^-1. A variety of results relating to the effect is deduced from elementary thermodynamics. For a very weak itinerant ferromagnet corrections to the result deduced from the Belov equation are obtained. Reference is made to recent measurements by Fawcett et al. on dilute platinum and palladium alloys.