Parametric excitation of eigenmodes in microscopic magnetic dots

We utilize time- and space-resolved Brillouin light scattering spectroscopy to study the parametric excitation of spin-wave eigenmodes in microscopic Permalloy dots. We show that the fundamental center eigenmode has the smallest excitation threshold. With the increase of the pumping power above this threshold, higher-order dipole-dominated eigenmodes with both even and odd spatial symmetry also become excited. At microwave power levels far above the threshold, the multimode excitation regime is suppressed due to the parametric excitation of short-wavelength exchange-dominated spin-wave modes. Our results provide important insight into the physics of parametric processes in microscopic magnetic systems.