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. (C) 2008 Elsevier B. V. All rights reserved.