Reciprocal spin Hall effects in conductors with strong spin-orbit coupling: a review

TL;DR

This review discusses the reciprocal spin Hall effects in conductors with strong spin-orbit coupling, focusing on the spin Hall angle and spin diffusion length across various materials, crucial for spintronic applications.

Contribution

It provides a comprehensive overview of the spin Hall angle and spin diffusion length measurements in different materials using the spin absorption method.

Findings

Spin Hall angle varies significantly among materials.

Spin diffusion length depends on material composition and structure.

The spin absorption method effectively characterizes spin transport properties.

Abstract

Spin Hall effect and its inverse provide essential means to convert charge to spin currents and vice versa, which serve as a primary function for spintronic phenomena such as the spin-torque ferromagnetic resonance and the spin Seebeck effect. These effects can oscillate magnetization or detect a thermally generated spin splitting in the chemical potential. Importantly this conversion process occurs via the spin-orbit interaction, and requires neither magnetic materials nor external magnetic fields. However, the spin Hall angle, i.e., the conversion yield between the charge and spin currents, depends severely on the experimental methods. Here we discuss the spin Hall angle and the spin diffusion length for a variety of materials including pure metals such as Pt and Ta, alloys and oxides determined by the spin absorption method in a lateral spin valve structure.