Generation of localized, half-frequency spin waves in micron sized ferromagnetic stripes: Experiments and simulations

We demonstrate the nonlinear generation of spin-wave edge modes with half the frequency of the applied oscillating field in a Co25Fe75 ferro- magnetic stripe through micromagnetic simulations and experiments. The generation of half-frequency modes depends on the simultaneous presence of resonances near both the driving frequency and the half-frequency in different regions of the material. The half-frequency genera- tion occurs in a system that is thin enough that typical three-magnon decay would not be allowed in a ferromagnetic resonance experiment in an extended film. We find that a limited range of driving frequencies will produce a half-frequency for a given set of system parameters. This range can be tuned by the strength of the oscillating field and the strength of the static external field. Our experimental results agree well with the findings from the simulations.