Skyrmions-based magnetic racetrack memory

Abstract

Magnetic skyrmions are topologically stable spin configurations with small size, which can be driven into motion by a small current. They are widely regarded as building blocks for next-generation magnetic storage. The main advantage of skyrmions lies in their particular dynamic behaviors, especially in their ability to move stably in racetrack under the action of small spin-polarized currents. The writing, driving and reading methods of skyrmions in racetrack are reviewed in detail in this paper, including the most recent research findings. The review focuses on the most commonly used driving method, i.e., driving skyrmions by applying spin-polarized currents. The clogging and annihilation of skyrmions in racetrack are analyzed, with the skyrmion Hall effect discussed which may lead skyrmion signals to lose. Methods to avoid skyrmion Hall effect are introduced and hence the optimized designs for skyrmion-based racetrack are also reviewed. Finally, some challenges of skyrmion-based racetrack memory are discussed.