Control of current-induced skyrmion motion in ratchet-type skyrmion-based racetrack memory with a loop structure

Abstract We propose a method to realize a ratchet-type skyrmion-based racetrack memory with a loop structure using current and validate the proposed method using micromagnetic simulations. The proposed method utilizes the ratchet effect composed of a gradient with perpendicular magnetic anisotropy (PMA). The skyrmion moves circularly inside a track, which is composed of regions with various gradients of PMA. The results demonstrate that the recording density and operating frequency of the memory are approximately 40 Gbit inch –2 and 42 MHz, respectively, when the diameter of the skyrmion is 28.1 nm.