Detecting single nanomagnet dynamics beyond the diffraction limit in varying magnetostatic environments

As areal bit density increases, characterizing individual magnetic bits within dense arrays becomes difficult with diffraction-limited optics. We demonstrate that dynamic magneto-optical detection breaks this diffraction limit if the characteristic behavior of a nanomagnet is sufficiently different from its neighbors’. We use far-field time-resolved Kerr microscopy to resolve the high-frequency magnetization dynamics of a single, small (Ø150 nm) nanomagnet within a low-frequency background from an array of large (Ø500 nm) magnets. We use this technique to observe and quantify the effects of magnetostatic interactions on the single magnet dynamics as the intermagnet spacing is varied.