Spin Seebeck effect and spin Hall magnetoresistance in the Pt/Y₃Fe₅O₁₂ heterostructure under laser-heating

In the previous study of longitudinal spin Seebeck effect (LSSE), the thermal gradient was often generated by inserting the sample between the cool bath and the hot bath. For practical use, this method is too cumbersome to be easily integrated into modern electrical circuits. Since the laser can be easily focused into a small region, it will be more convenient and friendly to the integrated circuit. In this paper, we systematically investigate the LSSE and spin Hall magnetoresistance (SMR) of the Pt/Y₃Fe₅O₁₂ heterostructure under focused laser-heating. We find that the extremely large voltage of inverse spin Hall effect (V_ISHE) can be obtained by reducing the diameter of laser or increasing the number of light spots. Meanwhile, even under the illumination of the ultraviolet light which will excite the electron from the valence band to the conduction band in yttrium iron garnet (YIG), the magnitude of SMR is nearly constant. It indicates that the spin transport behavior of the adjacent Pt is independent of the electron configuration of YIG. The laser-heating method to generate LSSE will be very promising for modern integrated electronic circuits and will promote the application of spin caloritronics in practice.