  We report current-induced spin torques in epitaxial NiMnSb films on a
commercially available epi-ready GaAs substrate. The NiMnSb was grown by
co-sputtering from three targets using optimised parameter. The films were
processed into micro-scale bars to perform current-induced spin-torque
measurements. Magnetic dynamics were excited by microwave currents and electric
voltages along the bars were measured to analyse the symmetry of the
current-induced torques. We found that the extracted symmetry of the spin
torques matches those expected from spin-orbit interaction in a tetragonally
distorted half-Heusler crystal. Both field-like and damping-like torques are
observed in all the samples characterised, and the efficiency of the
current-induced torques is comparable to that of ferromagnetic metal/heavy
metal bilayers.
