  In the increasing interests on spin-orbit torque (SOT) with various magnetic
materials, we investigated SOT in rare earth-transition metal ferrimagnetic
alloys. The harmonic Hall measurements were performed in Pt/GdFeCo bilayers to
quantify the effective fields resulting from the SOT. It is found that the
damping-like torque rapidly increases near the magnetization compensation
temperature TM of the GdFeCo, which is attributed to the reduction of the net
magnetic moment.
