Using nonlinear dynamics to understand spin wave interactions

It is pointed out that nonlinear interactions in yttrium-iron-garnet cause complex, low-frequency signals seen during ferromagnetic resonance experiments. Modeling this nonlinear behavior is difficult. Most attempts to model these low-frequency oscillations have attempted to reproduce quantities such as oscillation frequency or instability threshold. Methods from nonlinear dynamics have been used to characterize complex behavior measured in ferromagnetic resonance experiments. It is found that these quantities are useful in understanding the interactions in yttrium-iron-garnet. Simple numerical models are used to suggest which quantities are most important in characterizing these spin wave interactions