Time-resolved measurement of magnetization vectors driven by pulsed spin-orbit torque

Abstract

© 2021 Author(s). Published under an exclusive license by AIP Publishing. Spin-orbit torque (SOT) enables the efficient manipulation of magnetization with charge current injection. Electronic measurement techniques have been widely used as common experimental tools for SOT analysis (e.g., anomalous Hall measurement, spin-transfer ferromagnetic resonance, and planar Hall effect). However, electronics-based techniques usually observe the final static states of the magnetization motion of the ferromagnetic layer, and it is difficult to observe detailed kinetics during ultrafast operation. Here, we introduce a time-resolved measurement technique for a pulsed SOT. We investigate the precessional motion of the magnetization vector, driven by a pulsed SOT, employing the time-resolved magneto-optical Kerr effect. A fabricated photoswitch can convert an optical pulse into a charge current pulse that results in a pulsed SOT. We believe that this time- and vector-resolved measurement would be useful for studying the underlying mechanisms of SOT.