Large spin-charge interconversion induced by interfacial spin-orbit coupling in a highly conducting all-metallic system

TL;DR

This study demonstrates a significant spin-charge interconversion at a highly conductive Au/Cu interface driven by interfacial spin-orbit coupling, offering a simpler alternative to traditional systems for spintronic applications.

Contribution

The paper identifies the interfacial inverse spin galvanic effect as the source of spin-charge conversion in Au/Cu, distinct from bulk spin Hall effects, and introduces parameters for quantifying interfacial spin-orbit effects.

Findings

Large spin-charge interconversion at Au/Cu interface.

Interfacial effect dominates over bulk spin Hall effect.

Benchmarking parameters for spin-charge conversion quantification.

Abstract

Spin-charge interconversion in systems with spin-orbit coupling has provided a new route for the generation and detection of spin currents in functional devices for memory and logic such as spin-orbit torque switching in magnetic memories or magnetic state reading in spin-based logic. Disentangling the bulk (spin Hall effect) from the interfacial (inverse spin galvanic effect) contribution has been a common issue to properly quantify the spin-charge interconversion in these systems, being the case of Au paradigmatic. Here, we obtain a large spin-charge interconversion at a highly conducting Au/Cu interface which is experimentally shown to arise from the inverse spin galvanic effect of the interface and not from the spin Hall effect of bulk Au. We use two parameters independent of the microscopic details to properly quantify the spin-charge interconversion and the spin losses due to the interfacial spin-orbit coupling, providing an adequate benchmarking to compare with any spin-charge interconversion system. The good performance of this metallic interface, not based in Bi, opens the path to the use of much simpler light/heavy metal systems.