Spectroscopy and imaging of edge modes in Permalloy nanodisks.

We report ferromagnetic resonance force microscopy of confined spin-wave modes with improved, 100 nm resolution. The ferromagnetic resonance spectra in Permalloy disks (diameters ranging from 100 to 750 nm) distinguish multiple edge modes, and the images reveal distinct precession patterns. The fundamental edge mode also provides a new, localized probe of the magnetic properties of the film edge; rotation of the applied field reveals large edge property variations in nominally circular disks. As a function of disk diameter, the number of observed edge modes agrees with modeling.