Identification of a Large Number of Spin-Wave Eigenmodes Excited by Parametric Pumping in Yttrium Iron Garnet Microdisks

We present the parametric excitation of spin-wave modes in yttrium iron garnet (YIG) microdisks via parallel pumping. Their spectroscopy is performed using magnetic resonance force microscopy (MRFM), while their spatial profiles are determined by microfocus Brillouin light scattering (BLS). We observe that almost all the fundamental eigenmodes of an in-plane magnetized YIG microdisk, calculated using a micromagnetic eigenmode solver, can be excited using the parallel pumping scheme, as opposed to the transverse one. A comparison between the MRFM and BLS data on the one hand, and the simulations on the other hand, provides the complete spectroscopic labeling of over 40 parametrically excited modes. Our findings could be promising for spin-wave-based computation schemes, in which the amplitudes of a large number of spin-wave modes have to be controlled.