Spin–Orbit‐Torque‐Driven Perpendicular Switching of Interfacial High‐Anisotropy Pinning Spins without a Bias Field

The electrical control of perpendicular magnetization in ferromagnetic (FM)/antiferromagnetic (AFM) heterostructures is crucial for next‐generation spintronic devices. In this micromagnetic study, we demonstrate perpendicular exchange bias in the CoFeB/IrMn system and achieve field‐free perpendicular magnetization switching (PEB) of CoFeB via spin–orbit torque generated by the IrMn layer. Magnetization switching occurs through domain wall nucleation at the edges, but high anisotropy pinned spins at the interface generate a pinning force on the CoFeB layer that hinders domain wall propagation. Lower current densities reduce domain wall velocity, resulting in longer switching times. The application of an in‐plane magnetic field during SOT‐induced switching gives rise to oscillatory dynamics; however, increasing the damping effectively suppresses these precessional effects. Lower damping values, such as 0.025, lead to incomplete switching due to insufficient SOT energy dissipation, while increasing the damping value to 0.05 and above enables deterministic switching. The total energy increases with pinning density, likely due to the additional pinning energy introduced by interfacial pinned spins. Overall, this SOT‐driven, field‐free perpendicular switching presents a promising route toward advanced spintronic and quantum technology applications.