Persistent excitation of spin waves for kπ-state skyrmions

In this study, we investigated the micromagnetic dynamics of kπ-state skyrmions in a magnetic nanodot under a circular spinpolarized current and found an excited spin wave that can propagate persistently along the direction of the radius toward the center. This dynamic process is associated with two energetically favorable states in an oscillating period of spin waves. In this case, the spin-polarized current plays a role similar to effective perpendicular magnetic anisotropy and decreases the minimum energy in the magnetic system. Our findings provide insight into understanding the dynamic behaviors of topological magnetic textures.