Nonlinearity of the Susceptibility in Weak Ferromagnets and Antiferromagnets

摘要

The symmetry of the tensor describing the quadratic dependence of the magnetization on an applied field is studied for the various magnetic point groups. It is described by at most one parameter in antiferromagnetic materials, and up to ten in ferromagnetic materials. This parameter is calculated from basic principles to various approximations for FeF2 and CoF2. (Author)