Nonlinear Ferromagnetic Resonance in the Presence of Three-Magnon Scattering in Magnetic Nanostructures

Bulk and patterned ferromagnets can exhibit various nonlinear phenomena at moderate excitation power, making them a nice test bed for study of nonlinear dynamics. We investigate nonlinear ferromagnetic resonance in magnetic nanostructures with discrete spectra of spin-wave modes in the case of allowed three-magnon scattering processes. These processes result in the splitting of a directly driven spin-wave mode into two secondary modes, if a certain excitation threshold is overcome. The three-magnon splitting manifests itself as a characteristic distortion of the resonance curve, which can be detected in a simple ferromagnetic resonance experiment. Theoretical results are also compared to the experimental study of nonlinear spin-wave dynamics in a vortex-state magnetic disk, in which three-magnon splitting is confirmed by direct measurements using Brillouin light-scattering microscopy.