Interface transparency to orbital current

TL;DR

This study investigates the interface transparency to orbital currents in Cr/X/Ni trilayers, revealing that orbital current transfer efficiency is comparable or superior to spin currents across various spacers, advancing understanding of orbital transport.

Contribution

It demonstrates that orbital current interface transparency in Cr/X/Ni systems is comparable or higher than spin current transparency, providing new insights into orbital transport mechanisms.

Findings

Orbital current transfer efficiency is comparable or higher than spin current.

Interface transparency to orbital currents is consistent across different spacers.

Orbital currents can be effectively transferred across interfaces in multilayer structures.

Abstract

The transport of spin currents across interfaces is relatively well studied, while the transport properties of orbital currents are just starting to be examined. In Cr/Ni bilayers, the spin-orbit torque (SOT) due to the orbital current generated in the Cr layer is believed to dominate over torques of other origins. In this work, we study SOT in Cr/X/Ni trilayers, where X is an ultra-thin spacer of a different material. Using the SOT as a proxy for the orbital current transferred from the Cr to the Ni layer, we compare Cr/X/Ni results to Pt/X/Ni, the system in which spin current generated in the Pt layer plays a dominant role. We find that across 12 different spacers the apparent interface transparency to the orbital current is comparable or larger than to the spin current.