Interfacial Dzyaloshinskii-Moriya interaction and spin-orbit torque in Au1-xPtx/Co bilayers with varying interfacial spin-orbit coupling

TL;DR

This study demonstrates that interfacial Dzyaloshinskii-Moriya interaction (DMI) and spin-orbit torque (SOT) in Au1-xPtx/Co bilayers are influenced by interfacial orbital hybridization and composition-dependent effects, challenging previous assumptions of linearity with interfacial SOC.

Contribution

The paper provides conclusive experimental evidence that interfacial DMI is not necessarily linearly related to interfacial SOC and highlights the role of orbital hybridization and composition in tuning these effects.

Findings

Interfacial DMI is not a linear function of interfacial SOC.

{ au}DL varies with composition independently of interfacial Rashba-Edelstein effect.

Interfacial orbital hybridization critically influences DMI and SOT.

Abstract

The quantitative roles of the interfacial spin-orbit coupling (SOC) in Dzyaloshinskii-Moriya interaction (DMI) and dampinglike spin-orbit torque ({\tau}DL) have remained unsettled after a decade of intensive study. Here, we report a conclusive experiment evidence that, because of the critical role of the interfacial orbital hybridization, the interfacial DMI is not necessarily a linear function of the interfacial SOC, e.g. at Au1-xPtx/Co interfaces where the interfacial SOC can be tuned significantly via strongly composition (x)-dependent spin-orbit proximity effect without varying the bulk SOC and the electronegativity of the Au1-xPtx layer. We also find that {\tau}DL in the Au1-xPtx/Co bilayers varies distinctly from the interfacial SOC as a function of x, indicating no important {\tau}DL contribution from the interfacial Rashba-Edelstein effect.