Magnetoelastic oscillations in ferromagnets with cubic symmetry

Abstract

This is a study of the influence of magnetoelastic interactions on the properties of ferromagnets with cubic symmetry. The dispersion relations for coupled magnetoelastic waves are calculated for all the ground states of a ferromagnet with cubic symmetry. It is shown that the magnetoelastic interaction coefficient depends on the directions of the magnetic moment of the ferromagnet and the external magnetic field, as well as on the direction of the wave vector of the collective oscillations. These results are used as the basis for quantitative calculations of the dispersion relations for an NiMnGa alloy with shape memory. The features of the magnetoelastic interaction owing to martensite phase transitions in which one of the elastic moduli becomes anomalously small are discussed. These calculations show that a reduction in the elastic moduli of the crystal causes a substantial increase in the magnetoelastic interaction. It is also shown that the existence of a magnetoelastic interaction leads to a decrease...