Fig. 2
From: Observation of spin-orbit effects with spin rotation symmetry
Current-induced damping-like torque. a Experimental configuration for measuring the SOTs by MOKE magnetometry. b The polar MOKE response, ψpolar, measured in the test and control samples when current is applied parallel to H ext (ϕ = 0°). No dependence on \(\hat {\bf{m}}\) is observed. The measurement geometry (for simplicity we omit the Pt capping and seed layers) and the effective fields applied on the sample are also shown. c The polar MOKE response measured in the test and control samples when current is applied perpendicular to H ext (ϕ = 90°). In the test sample, the polar MOKE response is reversed when \(\hat {\bf{m}}\) is reversed. In contrast, the polar MOKE response in the control sample has little dependence on \(\hat {\bf{m}}\). The weak hysteresis-like signal in the control sample is likely due to small misalignment (∼1.5°) of H ext. d The angle dependence of \(\Delta {{\psi }}_{{\rm{polar}}}^{{\rm{even}}}\) and \(\Delta {{\psi }}_{{\rm{polar}}}^{{\rm{odd}}}\) of the test sample, where we define \(\Delta {{\psi }}_{{\rm{polar}}}^{{\rm{even}}} = \left( {{{\psi }}_{{\rm{polar}}}^{ + \; + } - {{\psi }}_{{\rm{polar}}}^{ + \; - }} \right) + \left( {{{\psi }}_{{\rm{polar}}}^{ - \; + } - {{\psi }}_{{\rm{polar}}}^{ - \; - }} \right)\) and \(\Delta {{\psi }}_{{\rm{polar}}}^{{\rm{odd}}} = \left( {{{\psi }}_{{\rm{polar}}}^{ + \; + } - {{\psi }}_{{\rm{polar}}}^{ + \; - }} \right) - \left( {{{\psi }}_{{\rm{polar}}}^{ - \; + } - {{\psi }}_{{\rm{polar}}}^{ - \; - }} \right)\). The first superscript in \({{\psi }}_{{\rm{polar}}}^{ + \; + }\) denotes the sign of \(\hat {\bf{m}}\) and the second superscript denotes the sign of \({\hat {\bf{m}}_{{\rm{Py}}}}\). The red lines are fittings using \(\Delta {{\psi }}_{{\rm{polar}}}^{{\rm{even}}} = 25.5\,{\rm{cos}}\left( {\frac{\pi }{{180}}\phi } \right)\) and \(\Delta {{\psi }}_{{\rm{polar}}}^{{\rm{odd}}} = 6.3\,{\rm{sin}}\left( {\frac{\pi }{{180}}\phi } \right)\) and the error bars represent the standard deviation calculated from the linear fitting in b used to calculate \(\Delta {{\psi }}_{{\rm{polar}}}^{{\rm{even}}}\) and \(\Delta {{\psi }}_{{\rm{polar}}}^{{\rm{odd}}}\)
