Fig. 4: Second harmonic Hall resistance and estimation of SOT efficiency.
From: Current-induced switching of a van der Waals ferromagnet at room temperature
a Schematic illustration of the second harmonic Hall (SHH) voltage measurement. External field \({H}_{{{{{{\rm{ext}}}}}}}\) is applied in the sample (\({xy}\) -) plane at an angle \(\phi\) from \(x\) - axis. Current is applied along \(x\) - axis and SHH voltage (\({V}_{{{{{{\rm{xy}}}}}}}^{2\omega }\)) is measured along the \(y\) - axis. b, c \({V}_{{{{{{\rm{xy}}}}}}}^{2\omega }\) measured for in-plane magnetic field rotation for (b) \({I}_{{{{{{\rm{ac}}}}}}}=\) 1 mA and (c) \({I}_{{{{{{\rm{ac}}}}}}}=\) 1.5 mA. Solid black lines fit to Eq. (2). Data offset in y-axis for clarity. d Hollow squares represent the amplitude of \(\cos \phi\) components of \({V}_{{{{{{\rm{xy}}}}}}}^{2\omega }\) in Eq. (3). Dotted lines are fits for the linear, thermal contribution to \({V}_{{{{{{\rm{xy}}}}}}}^{2\omega }\) from ordinary Nernst effect and spin Seebeck effect. e Anti-damping-like field contribution to \({V}_{{{{{{\rm{xy}}}}}}}^{2\omega }\) (solid squares) and their theoretical fit, with \({H}_{{{{{{\rm{k}}}}}}}=\) 38 kOe. Inset: \(\Delta {H}_{{{{{{\rm{DL}}}}}}}\) extracted for the two current level, and their fitting line, with near zero y-intercept. Error bars represent a 95% confidence interval. Measurements taken at 300 K.
