Observation of Skyrmions at Room Temperature in Co2FeAl Heusler Alloy Ultrathin Films

TL;DR

This paper reports the first observation of stable magnetic skyrmions at room temperature in unpatterned Co2FeAl thin film heterostructures, demonstrating their potential for spintronic devices without nanostructuring.

Contribution

It demonstrates room temperature skyrmions in unpatterned ferromagnetic thin films with strong interfacial Dzyaloshinskii-Moriya interaction, confirmed by experiments and simulations.

Findings

Skyrmions observed at room temperature in unpatterned films

Strong interfacial Dzyaloshinskii-Moriya interaction confirmed by Brillouin light scattering

Multiple stable skyrmions can be stabilized by tuning film parameters

Abstract

Magnetic skyrmions are topological spin structures having immense potential for energy efficient spintronic devices. However, observations of skyrmions at room temperature are limited to patterned nanostructures. Here, we report the observation of stable skyrmions in unpatterned Ta/Co2FeAl(CFA)/MgO thin film heterostructures at room temperature and in zero external magnetic field employing magnetic force microscopy. The skyrmions are observed in a trilayer structure comprised of heavy metal (HM)/ferromagnet (FM)/Oxide interfaces which result in strong interfacial Dzyaloshinskii-Moriya interaction (i-DMI) as evidenced by Brillouin light scattering measurements, in agreement with the results of micromagnetic simulations. We also emphasize on room temperature observation of multiple skyrmions which can be stabilized for suitable choices of CFA layer thickness, perpendicular magnetic anisotropy, and i-DMI. These results open up a new paradigm for designing room temperature spintronic devices based on skyrmions in FM continuous thin films.