Magnetic order and excitations in amorphous ferromagnets

Abstract

Neutron polarisation techniques have been used to show that the magnetic structure of Fe-based ferromagnets is not a collinear structure. The degree of canting varies with the sample and there is little correlation in the canting from site to site. In Fe-Ni materials the degree of canting is increased with increasing Ni concentration. The canting arises either from random crystal-field effects or from competing exchange interactions. The measurements also showed inelastic scattering which is different from spin-wave scattering and may arise from the excitations responsible for the temperature dependence of the magnetisation.