Giant room temperature interface spin Hall and inverse spin Hall effects

TL;DR

This paper investigates the spin Hall effect in a platinum-permalloy bilayer, revealing a temperature-dependent spin Hall angle and a significant interface contribution that could impact spintronic device performance.

Contribution

It introduces a first-principles scattering approach to quantify the interface spin Hall angle, showing it dominates the inverse SHE at room temperature.

Findings

Spin Hall angle increases with temperature in Pt.

Interface spin Hall angle is giant and dominates inverse SHE.

Room temperature SHE and inverse SHE decomposed into bulk and interface contributions.

Abstract

The spin Hall angle (SHA) is a measure of the efficiency with which a transverse spin current is generated from a charge current by the spin-orbit coupling and disorder in the spin Hall effect (SHE). In a study of the SHE for a Pt$|$Py (Py=Ni$_{80}$Fe$_{20}$) bilayer using a first-principles scattering approach, we find a SHA that increases monotonically with temperature and is proportional to the resistivity for bulk Pt. By decomposing the room temperature SHE and inverse SHE currents into bulk and interface terms, we discover a giant interface SHA that dominates the total inverse SHE current with potentially major consequences for applications.