By micromagnetic simulations, we investigate the current-driven characteristics and applications of magnetic skyrmion strings. 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 can be realized by varying the driving current densities. Our findings will contribute to the further study of magnetic skyrmion strings for data storage, processing, and energy-efficient computing.

In this paper, we theoretically investigated the propagation characteristics of spin waves in skyrmion-based magnonic crystals. It is found that the dispersion relations can be manipulated by strains through magneto-elastic coupling. Especially, the allowed bands and forbidden bands in dispersion relations shifted to higher frequency with changing strains from compressive to tensile, while shifting to lower frequency with changing strains from tensile to compressive. We also confirmed that the spin waves with specific frequencies could pass the magnonic crystal or be blocked by tuning the strains. The result provides an advanced platform for tunable skyrmion-based spin wave devices.