Comparison between spin-orbit torques measured by domain-wall motions and harmonic measurements

Here we report the comparison of the spin torque efficiencies measured by three different experimental schemes for Pt/Co/X stacks with material X (= Pt, Ta, Ti, Al, Au, Pd, and Ru. 7 materials). The first two spin torque efficiencies epsilon((1))(DW) and epsilon((2))(DW) are quantified by the measurement of spin-torque-induced effective field for domain-wall depinning and creeping motions, respectively. The last one-longitudinal spin torque efficiency epsilon(L)-is measured by harmonic signal measurement of the magnetization rotation with uniform magnetization configuration. The results confirm that, for all measured Pt/Co/X stacks, epsilon((1))(DW) and epsilon((2))(DW) are exactly consistent to each other and these two efficiencies are roughly proportional to epsilon(L) with proportionality constant pi/2, which comes from the integration over the domain-wall configuration. (C) 2017 Author(s).