Suppression of the fieldlike spin-orbit torque efficiency due to the magnetic proximity effect in ferromagnet/platinum bilayers

TL;DR

This study investigates how the magnetic proximity effect in ferromagnet/platinum bilayers suppresses the fieldlike spin-orbit torque efficiency, revealing temperature-dependent behavior through magnetoresistive measurements.

Contribution

It demonstrates the suppression of fieldlike torque efficiency due to magnetic proximity effects in Co2FeAl/Pt bilayers, highlighting temperature dependence and the influence of platinum thickness.

Findings

Fieldlike torque efficiency decreases with lowering temperature.

Magnetic proximity effect enhances anomalous Hall and magnetoresistances at low temperatures.

Suppression of fieldlike torque linked to magnetic proximity effect influence.

Abstract

Current-induced spin-orbit torques in Co$_2$FeAl/Pt ultrathin bilayers are studied using a magnetoresistive harmonic response technique, which distinguishes the dampinglike and fieldlike contributions. The presence of a temperature-dependent magnetic proximity effect is observed through the anomalous Hall and anisotropic magnetoresistances, which are enhanced at low temperatures for thin platinum thicknesses. The fieldlike torque efficiency decreases steadily as the temperature is lowered for all Pt thicknesses studied, which we propose is related to the influence of the magnetic proximity effect on the fieldlike torque mechanism.