Controlling oscillation modes by manipulating dimensionality of spin structures

Abstract

Harmonic oscillation of spin structures has great potential for applications in nanotechnologies such as nano-oscillators [1] and neuromorphic computing [2, 3]. However, effectively tuning the oscillations over a wide frequency range within a single ferromagnetic nanoelement has not been studied experimentally or theoretically. In this work, by manipulating the dimensionality of a vortex core structure which is one of spin structures, we experimentally observe a drastic change in the oscillation of magnetic vortex, which is one of spin structures, over the frequency range from MHz to sub-GHz in a 100nm-thick permalloy circular disk [4]. Using time-resolved magnetic transmission x-ray microscopy, we revealed that the oscillation properties were observed to be significantly dependent on the dimensions and shape of the vortex core structure. In addition, we found that the various oscillation modes over a broad range of frequencies appear with dimensional change of the vortex core structure. This work will contribute to the oscillation-based technology by offering effective tuning of oscillations of the vortex core structure.