Strong Spin-Orbit Torque Induced by the Intrinsic Spin Hall Effect in Cr1-xPtx

TL;DR

This study demonstrates that Cr1-xPtx alloys, especially Cr0.2Pt0.8, exhibit strong spin-orbit torque driven by the intrinsic spin Hall effect, offering a low-resistivity, energy-efficient material for spintronic applications.

Contribution

It reveals the tunable spin-orbit torque in Cr1-xPtx alloys and links the effect to intrinsic spin Hall conductivity and carrier lifetime, highlighting a new material for spintronics.

Findings

Maximal dampinglike spin-orbit torque of 0.31 at Cr0.2Pt0.8

Spin current generation explained by intrinsic spin Hall conductivity

Cr role similar to other metals and oxides in spin current generation

Abstract

We report on a spin-orbit torque study of the spin current generation in Cr1-xPtx alloy, using the light 3d ferromagnetic Co as the spin current detector. We find that the dampinglike spin-orbit torque of Cr1-xPtx/Co bilayers can be enhanced by tuning the Cr concentration in the Cr1-xPtx layer, with a maximal value of 0.31 at the optimal composition of Cr0.2Pt0.8. We find that the spin current generation in the Cr1-xPtx alloy can be fully understood by the characteristic trade-off between the intrinsic spin Hall conductivity of Pt and the carrier lifetime in the dirty limit. We find no evidence for the spin current generation by other mechanisms in this material, revealing that the role of Cr is found to be simply the same as other metals and oxides in previous studies. This work also establishes the low-resistivity Cr0.2Pt0.8 as an energy-efficient spin-orbit torque provider for magnetic memory and computing technologies.