Magnetic domain wall motion and switching under microwave excitation

Abstract

Magnetic domain wall (DW) motion and magnetization switching in atomically thin films with perpendicular magnetic anisotropy are central to spintronic devices. Although magnetization precession is typically avoided to reduce damping losses, resonant excitation can assist magnetic switching. Here, the excitation of DWs by radio-frequency (RF) magnetic fields or RF currents and its impact on DW motion and switching are demonstrated. Resonantly excited DWs exhibit current-free, long-range self-propulsion under RF excitation and a transverse magnetic field, which sets the propagation direction. Moreover, RF excitation sustains current-induced DW motion for several microseconds after a nanosecond current pulse, requiring only a weak longitudinal field. RF excitation also enhances spin-orbit torque switching by facilitating DW expansion, highlighting the key role of DW motion. In addition, RF-assisted field switching and RF-induced demagnetization via ferromagnetic resonance are shown.