Perturbation technique for LLG equation

Summary form only given. Recently, analytical solutions of Landau-Lifshitz-Gilbert (LLG) equation for isotropic media and circularly polarized applied radio-frequency (RF) fields have been reported. These analytical solutions can be derived by using the rotational invariance of the system with respect to rotations around the symmetry axis. In fact, the presence of rotational symmetry permits one to reduce the problem to the study of an autonomous dynamical system on the sphere, amenable to an exact analytical treatment. The purpose of this paper is to extend this analytical solutions to the case of anisotropic media and elliptically polarized applied RF fields. This is accomplished by treating anisotropic media and elliptically polarized fields as perturbations of isotropic media and circularly polarized fields, respectively.