Nonlinear subswitching regime of magnetization dynamics in photomagnetic garnets

We analyze, both experimentally and numerically, the nonlinear regime of photo-induced coherent magnetization dynamics in cobalt-doped yttrium iron garnet films. Photo-magnetic excitation with femtosecond laser pulses reveals a strongly response spin subsystem significant increase effective Gilbert damping. By varying fluence external magnetic field, we show that this nonlinearity originates anharmonicity energy landscape. numerically map parameter workspace for below photo-magnetic switching threshold. Corroborated by numerical simulations Landau-Lifshitz-Gilbert equation, our results highlight key role cubic symmetry reaching precession regime. These findings expand fundamental understanding laser-induced as well facilitate development applied photo-magnetism.