Observation of pure inverse spin Hall effect in ferromagnetic metals by FM/AFM exchange bias structures

Abstract

We report that the spin current generated by spin Seebeck effect (SSE) in yttrium iron garnet (YIG) can be detected by a ferromagnetic metal (NiFe). By using the FM/AFM exchange bias structure (NiFe/IrMn), inverse spin Hall effect (ISHE) and planar Nernst effect (PNE) of NiFe can be unambiguously separated, allowing us to observe a pure ISHE signal. After eliminating the in plane temperature gradient in NiFe, we can even observe a pure ISHE signal without PNE from NiFe itself. It is worth noting that a large spin Hall angle (0.098) of NiFe is obtained, which is comparable with Pt. This work provides a kind of FM/AFM exchange bias structures to detect the spin current by charge signals, and highlights ISHE in ferromagnetic metals can be used in spintronic research and applications.