Manipulating movement of skyrmion by strain gradient in a nanotrack

Magnetic skyrmions are swirling nanometric spin textures, which have attracted extensive attention by virtue of their potential applications as information carriers for future memory technology and spintronic devices. Here, we investigate the effect of strain gradient on the in-plane current-driven motion of magnetic skyrmion in a nanotrack. It is found that a longitudinal strain gradient will induce a transverse velocity with its value linearly proportional to the strain gradient. As well, we find that skyrmions can be accelerated or decelerated by the boundary of nanotrack. This behavior depends on the repulsive force induced by boundary and the topological number of skyrmion. Our results not only explain the effect of strain gradient, but also show the influence of the boundary on the skyrmion motion. This work may provide a guide for designing and developing the racetrack memory based on magnetic skyrmions.