Current-induced spin torques on single GdFeCo magnetic layers

TL;DR

This paper demonstrates strong current-induced spin torques in single GdFeCo layers due to intrinsic spin-orbit coupling, eliminating the need for heavy metal layers and enabling new spintronics functionalities.

Contribution

It introduces a novel material architecture using GdFeCo layers that generate self-torques without heavy metal layers, leveraging intrinsic SOC and interface engineering.

Findings

Strong self-torques observed in GdFeCo layers.

Enhanced spin current emission near the magnetization compensation temperature.

Tunable spin torques by adjusting spin absorption outside the layer.

Abstract

Spintronics exploits spin-orbit coupling (SOC) to generate spin currents, spin torques, and, in the absence of inversion symmetry, Rashba, and Dzyaloshinskii-Moriya interactions (DMI). The widely used magnetic materials, based on 3d metals such as Fe and Co, possess a small SOC. To circumvent this shortcoming, the common practice has been to utilize the large SOC of nonmagnetic layers of 5d heavy metals (HMs), such as Pt, to generate spin currents by Spin Hall Effect (SHE) and, in turn, exert spin torques on the magnetic layers. Here, we introduce a new class of material architectures, excluding nonmagnetic 5d HMs, for high-performance spintronics operations. We demonstrate very strong current-induced torques exerted on single GdFeCo layers due to the combination of large SOC of the Gd 5d states, and inversion symmetry breaking mainly engineered by interfaces. These "self-torques" are enhanced around the magnetization compensation temperature (close to room temperature) and can be tuned by adjusting the spin absorption outside the GdFeCo layer. In other measurements, we determine the very large emission of spin current from GdFeCo. This material platform opens new perspectives to exert "self-torques" on single magnetic layers as well as to generate spin currents from a magnetic layer.