Effective Manipulation of Skyrmions via Strain Gradient

Skyrmion-based devices hold considerable potential for memory, logic, and sensing applications, where precise control over skyrmion density and size is essential. While strain engineering offers an energy-efficient route to tune these properties, excessive strain can induce plastic deformation in magnetic films or lead to cracking, compromising the reliability of strain-mediated skyrmion control. Here, we demonstrate strain gradients as an effective additional control parameter in magnetic multilayers. By introducing microscale periodic wrinkled structures in sputtered Pt/Co/Ta multilayers, strain gradients with varying magnitudes and directions are generated. Magnetic force microscopy reveals that both skyrmion density and size vary synchronously with the in-plane strain gradient, enabling broader tunability than uniform strain approaches. Micromagnetic simulations confirm that these effects arise from strain and strain gradient modulation of the Dzyaloshinskii-Moriya interaction and magnetic anisotropy. Moreover, this control strategy is reversible, cyclable, and transferable across different magnetic multilayers, providing a practical avenue for precise skyrmion engineering. This approach offers significant promise for advancing flexible spintronics, skyrmion-based memory, and neuromorphic computing architectures.