Quantification of spin accumulation causing spin-orbit torque in Pt/Co/Ta stack

TL;DR

This paper experimentally quantifies spin accumulation caused by spin-orbit coupling in a Pt/Co/Ta stack, demonstrating its dependence on layer thickness and current, with significant implications for spintronic device efficiency.

Contribution

It provides the first detailed measurement of spin accumulation in this specific stack, showing how it can be tuned and its relation to spin Hall angles.

Findings

Spin accumulation can reach over 10% of local magnetization at high current densities.

Spin accumulation depends on Ta layer thickness, aligning with spin Hall angle trends.

Quantification method enables better understanding of spin-orbit torque mechanisms.

Abstract

Spin accumulation induced by spin-orbit coupling is experimentally quantified in stack with in-plane magnetic anisotropy via the contribution of spin accumulation to Hall resistances. Using a biasing direct current the spin accumulation within the structure can be tuned, enabling quantification. Quantification shows the spin accumulation can be more than ten percentage of local magnetization, when the electric current is 1E11 A/m*m. The spin accumulation is dependent of the thickness of Ta layer, the trend agrees with that of spin Hall angle indicating the capability of Ta and Pt in generating spins.