Perturbation technique for LLG dynamics in uniformly magnetized bodies subject to RF fields

The problem of magnetization dynamics of a uniformly magnetized uniaxial particle or film, under elliptically polarized applied field, is considered. In the special case of circularly polarized applied field and particles (films) with a symmetry axis, pure time-harmonic magnetization modes exist that can be computed analytically. Deviations from these highly symmetric conditions are treated as perturbation of the symmetric case. The perturbation technique leads to the exactly solvable system of linear differential equations for the perturbations which enables one to compute higher order magnetization harmonic. The analytical solutions are obtained and then compared with numerical results.