Engineering of magnetic domain walls via antidot geometry for advanced multi-state memory applications.

Understanding and controlling domain wall (DW) dynamics is pivotal for the development of racetrack memory and spintronic logic devices. This study presents a comprehensive micromagnetic investigation into DW pinning and depinning in in-plane magnetized nanowires featuring circular antidots. The effects of antidot radius, current density, and saturation magnetization (Ms) on DW motion is systematically analyzed. Results reveal critical thresholds for depinning, nonlinear velocity profiles, and non-monotonic responses to antidot size highlighting the interplay between spin-transfer torque and geometric confinement. Additionally, a multi-bit-per-cell memory concept is demonstrated using graded antidot arrays, where current-controlled DW progression encodes discrete magnetic states. These findings offer design guidelines for robust and efficient domain wall manipulation in future high-density spintronic devices.