Nonlinear magnetization dynamics under circularly polarized field

Exact analytical results are presented For the nonlinear large motion of the magnetization vector in a body with uniaxial symmetry subject to a circularly polarized held. The absence of chaos, the existence of pure time-harmonic magnetization modes with no generation of higher-order harmonics, and the existence of quasiperiodic magnetization modes with spontaneous breaking of the rotational symmetry are proven. Application to ferromagnetic resonance and connection with the Stoner-Wohlfarth model are discussed. DOI: 10.1103/PhysRevLett.86.724.