Electric detection of the spin-Seebeck effect in ferromagnetic metals (invited)

The spin-Seebeck effect (SSE) converts a temperature gradient into spin voltage, driving force for nonequilibrium spin currents, in a ferromagnetic metal. In this study, the SSE in ferromagnetic [formula omitted], Ni, and Fe films has been investigated by means of the inverse spin-Hall effect (ISHE) in Pt films at room temperature. The ISHE allows us to detect the SSE signals as electric voltage separated from extrinsic thermoelectric effects. The experimental results show that the sign of the thermally induced spin voltage due to the SSE is reversed between the higher- and lower-temperature ends of the ferromagnets. We also measured the spatial distribution and the sample-width dependence of the ISHE voltage induced by the SSE.