Extraction of the spin torque non-adiabaticity from thermally activated domain wall hopping

We investigate the non-adiabaticity of current-induced domain wall motion by time resolved analysis of thermally activated domain wall motion between two metastable states within a Co/Pt multilayer wire with a strong uniaxial perpendicular anisotropy. By measuring the dwell times for which the domain wall remains in one state, we deduce the non-adiabaticity factor ß using two independent approaches: (i) the dependence of the dwell times on the injected current and (ii) the current-field equivalency. The comparison of the results allows us to gauge their reliability and the observed differences highlight the importance of the two dimensional (2D) nature of the domain wall.