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

TL;DR

This paper demonstrates the detection of pure inverse spin Hall effect in ferromagnetic NiFe using FM/AFM exchange bias structures, revealing significant spin Hall angles and advancing spin current detection methods in spintronics.

Contribution

It introduces a novel FM/AFM exchange bias structure to isolate and observe pure ISHE signals in ferromagnetic metals, enabling improved spin current detection.

Findings

Pure ISHE signals observed in NiFe without PNE interference

Large spin Hall angle of 0.098 in NiFe, comparable to Pt

FM/AFM structures effectively separate spin and thermal effects

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.