Control of out-of-plane anti-damping spin torque with a canted ferromagnetic spin source

TL;DR

This paper demonstrates how a canted ferromagnetic SrRuO3 layer can produce and tune out-of-plane anti-damping spin-orbit torques, advancing control of magnetic memory switching.

Contribution

It introduces a canted ferromagnetic layer configuration to generate and control out-of-plane anti-damping spin-orbit torques in nanoscale magnetic devices.

Findings

Canted SrRuO3 layer produces measurable out-of-plane anti-damping torque.

The out-of-plane torque can be tuned by magnetic moment orientation.

Both anomalous Hall and planar Hall effects contribute to the torque.

Abstract

To achieve efficient anti-damping switching of nanoscale magnetic memories with perpendicular magnetic anisotropy using spin-orbit torque requires that the anti-damping spin-orbit torque have a strong out-of-plane component. The spin anomalous Hall effect and the planar Hall effect spin current produced by a ferromagnetic layer are candidate mechanisms for producing such an out-of-plane anti-damping torque, but both require that the magnetic moment of the spin source layer be canted partly out of the sample plane at zero applied magnetic field. Here we demonstrate such a canted configuration for a ferromagnetic SrRuO3 layer and we characterize all vector components of the torque that it produces, including non-zero out-of-plane anti-damping torques. We verify that the out-of-plane spin component can be tuned by the orientation of magnetic moment, with significant contributions from both the spin anomalous Hall effect and the planar Hall effect spin current.