Distinct detection of thermally induced spin voltage in Pt/WS2/Ni81Fe19 by inverse spin Hall effect

Conversion of heat into a spin current by means of the spin Seebeck effect (SSE) is one of the exciting topics in spin caloritronics. Using this technique, the excess heat may be transformedinto a valuable electric voltage by coupling SSE with inverse spin Hall effect (ISHE). In this study, a thermal gradient and an in-plane magnetic field are used as the driving power to mobilize the spin electrons to produce SSE. A spin voltage is detected by ISHE in the Ni81Fe19 heterostructure by means of a WS2/Pt strip. Using WS2 sheets of different thicknesses, a large spin Seebeck coefficient of 0.72 µV/K is obtained, which is twelve times greater than the conventional spin Seebeck coefficient observed in Pt/Ni81Fe19 bi-layer devices. We observe the thickness dependence of tungsten disulfide (WS2) flakes and the polarity reversal of pure SSE signals that are measured without influence from the other thermoelectric effects in our Pt/WS2/Ni81Fe19 device—the most intriguing feature of this study. Without the electric ...