  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.
