Current-induced magnetic skyrmions oscillator

TLDR

Spin‑transfer nano‑oscillators are promising nanoscale microwave sources that should be compact, operate over a wide frequency range, have narrow linewidths, high output power, and low power consumption. The study aims to demonstrate that magnetic skyrmions can be driven into oscillation by a spin‑polarized current, proposing a new skyrmion‑based STNO. Micromagnetic simulations were employed to show that a spin‑polarized current excites skyrmion oscillations. The skyrmion oscillator can operate from near‑zero to gigahertz frequencies, achieve linewidths below 1 MHz, function at current densities as low as 10^8 A m⁻², and is expected to enhance output power, offering a promising route for skyrmion‑based microwave generators.

Abstract

Spin transfer nano-oscillators (STNOs) are nanoscale devices which are promising candidates for on-chip microwave signal sources. For application purposes, they are expected to be nano-sized, to have broad working frequency, narrow spectral linewidth, high output power and low power consumption. In this paper, we demonstrate by micromagnetic simulation that magnetic skyrmions, topologically stable nanoscale magnetization configurations, can be excited into oscillation by a spin-polarized current. Thus, we propose a new kind of STNO using magnetic skyrmions. It is found that the working frequency of this oscillator can range from nearly 0 Hz to gigahertz. The linewidth can be smaller than 1 MHz. Furthermore, this device can work at a current density magnitude as small as 108 A m−2, and it is also expected to improve the output power. Our studies may contribute to the development of skyrmion-based microwave generators.