Nonlinear response of uniaxial ferromagnets and applications to surface magnetostatic waves

Abstract The nonlinear susceptibilities of uniaxially anisotropic ferromagnets are obtained analytically. The expressions show that the anisotropy effect on the first- and second-order components means just an increased H1a (the first-order anisotropy field) of the dc field H0 along the anisotropy axis, but the third-order components are complicated and new terms appear. Applying the above results to surface magnetostatic waves in the films, we find new magnetostatic modes from the joint effect of the anisotropy and nonlinearity since higher powers of frequency are introduced in the dispersion equation by the nonlinearity and anisotropy. Very obvious non-reciprocity is seen from the dispersion curves.