Non-linear response of driven spin excitations

Brillouin scattering was used to study the effect of high-power microwave fields on an array of permalloy particles and the results are compared with simulations. The simulations are of two types: one is based on a model in which each particle is treated as a single spin, the second model relies on generalized micromagnetic codes that include external driving fields and enable magnon–magnon coupling. Experimental results as well as simulations show clear, but sometimes different, evidence of non-linear behavior.