Skyrmion-based reconfigurable logic gates manipulated by voltage gates and notches in the synthetic antiferromagnetic nanotrack

Abstract Magnetic skyrmions are spin configurations with non-trivial topological states, suitable for future memory logic applications with non-volatile and high-speed information processing. However, skyrmions are affected by the skyrmion Hall effect when moving in ferromagnetic tracks, which limits their performance. In this work, we propose reconfigurable logic gates based on skyrmions for synthetic antiferromagnetic nanotracks. Through the manipulation of voltage gates and rectangular notches, seven logic functions have been achieved in the same track structure relying on the competition between spin transfer torque, skyrmion-skyrmion topological repulsion, skyrmion-edge repulsion, and voltage controlled magnetic anisotropy effects. We have found that within a certain range of the perpendicular magnetic anisotropy constant ( K uv ) and size of voltage gate, a single skyrmion is pinned by the energy barrier generated by voltage gate, while one of double skyrmions can pass through the energy barrier due to topological repulsion between skyrmions. The results revealed that the wider the energy barrier region, the easier it is to hinder the movement of skyrmions, and the smaller the critical K uv for skyrmions to break away from the energy barrier. On the other hand, the larger the potential well region generated by voltage gate, the easier it is for skyrmions to be attracted, and the larger the critical K uv for skyrmions to break free from the potential well. Furthermore, we have also found that double skyrmions are either simultaneously pinned by the potential well or pass through simultaneously in the structure. This work provides an effective method for controlling the moving behavior of skyrmions, which paves the way for the development of reconfigurable skyrmion logic gates for information processing.