Characteristics and Applications of Current-Driven Magnetic Skyrmion Strings

We investigate the current-driven characteristics and applications of magnetic skyrmion strings by micromagnetic simulations. Under the spin-polarized driving current, the skyrmion string presents different moving trajectories in different layers due to the skyrmion Hall effect. Moreover, a series of skyrmion bobbers can be generated with a notch defect placed in the surface and the skyrmion bobbers will follow the skyrmion string. By varying the current density, the bobbers' characteristics such as number and velocity can be manipulated, which inspires us to propose a skyrmion string-based diode. In addition, an AND logic gate and an OR logic gate in the identical scheme based on the skyrmion string are proposed. AND logic and OR logic behaviors can be realized by varying the driving current densities. Our findings will contribute to further research of magnetic skyrmion strings for data storage, processing, and energy-efficient computing.