Discovery of high temperature magnetic skyrmions and current-induced helicity reversal in a nanostructured frustrated magnet

Skyrmionic spin configurations have attracted considerable attention for their intriguing magneto-electrical properties. Here, we report the observation of frustrated magnetic skymrions with extremely high temperature stability in the magnetic alloy Fe₃Sn₂, and also the fabrication of skyrmion-based race-track memory devices. In this compound, the magnetic skyrmions possess various spin textures and can transform into each other under certain external magnetic fields. Furthermore, by using focused ion beam technology, a single skyrmion chain was fashioned into a geometrically confined race-track shape Fe₃Sn₂ nanostripe with a width of 600 nm. It was found that this single chain has extremely high temperature stability, and the size and interspacing of the skyrmion bubbles remain unchanged from room temperature up to a record-high 630 K. We also observed the current-induced helicity reversal of Bloch-type skyrmions in a nanostructured Fe₃Sn₂ frustrated magnet. The critical pulse current density required to trigger the helicity reversal is 10⁹-10¹⁰ A/m² with a corresponding pulse-width range of 1 μs-100 ns. Our realization of this new type of extremely stable magnetic skymrion and the fabrication of skyrmion-based race-track memory devices represent important steps towards the application of skyrmion-based spintronic devices.