Unusual inverse spin Hall effect in Pt/Co/Pt multilayers on single-crystalline YIG

The inverse spin Hall effect (ISHE) is a significant phenomenon that enables the conversion of spin current into charge current, offering promising applications in novel spintronic devices. In conventional ISHE measurements, it is widely recognized that the spin polarization, spin current, and generated charge current are mutually perpendicular. This study systematically investigates the ISHE in Pt/Co/Pt multilayers grown on a single-crystalline yttrium iron garnet (YIG) layer. A non-zero ISHE voltage was obtained along the direction parallel to the external magnetic field within the YIG coercive field range, deviating from the classical ISHE behavior. Our investigation revealed that the in-plane magnetic anisotropy of single-crystalline YIG plays a crucial role, as the easy axis of YIG and the external magnetic field collaboratively determine the polarization direction of the spin current, especially when the external magnetic field is smaller than the YIG coercive force. Furthermore, by tuning the small in-plane magnetization component of the Pt/Co/Pt multilayers, which couples with the YIG magnetization, we were able to control the shape and reversal path of the ISHE voltage loop. These findings deepen our understanding of how magnetic order affects charge current flow in ISHE measurements. The variety of ISHE voltage loop shapes and reversal paths observed suggest potential applications for this device as a magnetic field sensor.