Tuning Effective Spin Hall Angles via Oxygen Vacancies in Multiferroic BiFeO3‐Based Heterostructures

Abstract Recently, magnetization switching driven by spin–orbit torque (SOT) has been intensely studied. However, it is still a challenge to effectively control the spin Hall angle (SHA) and critical current density for SOT switching. With the help of multiferroic BiFeO 3 (BFO) thin films, a method to adjust SHA and the switching current is proposed. The BFO‐based heterostructures with opposite spontaneous polarization fields show huge changes in both perpendicular magnetic anisotropy and SOT‐induced magnetization switching. The variation of the effective SHAs for the heterostructures with opposite polarizations is estimated to be 272%, which can be attributed to the distribution of oxygen vacancies inside the BFO films. The possible applications of these structures in memory and reconfigurable logic devices are also demonstrated.