Current-induced skyrmion dynamics in a frustrated magnetic film.

Abstract

The magnetic skyrmion is an exotic and versatile topological object in condensed matter physics, which promises novel applications in electronic and spintronic devices [1–2]. Recently, a rich phase diagram of an anisotropic frustrated magnet and properties of frustrated skyrmions with arbitrary vorticity and helicity were investigated [3]. Other remarkable physical properties of skyrmions in the frustrated magnetic system have also been studied theoretically [4–6]. Here, we explore the skyrmion dynamics in a frustrated magnet based on the J1-J2-J3 classical Heisenberg model explicitly by including the dipole-dipole interaction [7]. The skyrmion energy acquires a helicity dependence due to the dipole-dipole interaction, resulting in the current-induced translational motion with a fixed helicity. The lowest-energy states are the degenerate Bloch-type states, which can be used for building the binary memory. By increasing the driving current, the helicity locking-unlocking transition occurs, where the translational motion changes to the rotational motion. Furthermore, we demonstrate that two skyrmions can spontaneously form a bound state. The separation of the bound state forced by a driving current is also studied. In addition, we show the annihilation of a pair of skyrmion and antiskyrmion. Our results reveal the distinctive frustrated skyrmions may enable new applications.