Stability and evolution of skyrmionium and skyrmions in a spherical shell

The study of magnetic structures, particularly those with curved geometries such as spherical shells, has obtained significant interest due to their potential applications in data storage, spintronics, and other advanced technologies. However, the effects of material parameters, geometric dimensions, and magnetic fields on the equilibrium and induced behaviors of skyrmions remain largely unresolved. Here, based on micromagnetic simulations, we firstly investigate the influence of spherical shell dimensions, magnetic anisotropy, exchange interaction, and Dzyaloshinskii–Moriya interaction on the magnetic states of spherical shells. We find that curvature effects become more pronounced with increasing thickness and decreasing radius, providing evidence for the role of curvature-induced DMI-like interactions in skyrmion formation. Additionally, we observe that applying a magnetic field to the spherical shell induces behaviors similar to those in disks, including the topological transition between skyrmionium and skyrmion states, the annihilation of skyrmions, and polarity reversal. Our study aims to advance the understanding of magnetic phenomena in curved geometries and contribute to the development of novel magnetic devices.