Autoresonance Excitation of Nonlinear Oscillations of Magnetization and Domain Walls in Ferromagnets

Abstract

We investigate the conditions of capturing into resonance and exciting nonlinear ferromagnetic resonance in a ferromagnetic film with the anisotropic easy plane, as well as autoresonance excitation of nonlinear oscillations of the domain wall in uniaxial ferromagnets. The investigations demonstrate that in easy-plane ferromagnets with a narrow resonance line nonlinear oscillations of magnetization in the autoresonance mode can be generated. This autoresonance takes place if the resonance field grows slowly and pumping frequency is the constant which is equal to the frequency of linear resonance. It has been established that effectively exciting nonlinear oscillations of the domain wall in uniaxial ferromagnets and controlling the wall dynamics by low-amplitude alternating fields with the slow variation of the planar field in the autophasing mode are possible in the case of weak dissipation.