Pure Inverse Spin Hall Effect in Ferromagnetic Ni80Fe20/Y3Fe5O12 (YIG) Heterostructures via the Longitudinal Spin Seebeck Effect

초록

Spin-charge interconversion in ferromagnetic metals provides an unconventional pathway to explore spin-orbit coupling beyond heavy nonmagnetic systems. While ferromagnetic Ni80Fe20 has long been regarded as a spin source, its role as a spin-current detector remains largely unexplored. Here, we demonstrate the direct detection of a pure inverse spin Hall effect (ISHE) in a Ni80Fe20 layer interfaced with a ferrimagnetic insulator, yttrium iron garnet (Y3Fe5O12, YIG). A thermally generated spin current produced by the longitudinal spin Seebeck effect (LSSE) in YIG is converted into a transverse charge voltage within the Ni80Fe20 layer. Importantly, systematic control experiments using Ni80Fe20/Al2O3 bilayers, combined with symmetry-controlled measurement geometries, quantitatively eliminate anomalous Nernst contributions, thereby establishing that the observed voltage originates intrinsically from the ISHE in ferromagnetic Ni80Fe20. These findings identify ferromagnetic metals as viable spin-current detectors and provide a conceptually simple platform for investigating spin-orbit interactions and spin caloritronic phenomena without relying on heavy nonmagnetic metals.

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