Fig. 4. Final results for the damping-like and field-like spin-orbit-torque efficiencies for the sample series substrate/Ta (1.5)/Pt (4)/Co (0.85 to 2.1)/MgO (1.9)/Ta (2).
The numbers in parentheses are thicknesses in nanometers. The pink line in (B) indicates the estimated Oersted torque based on the calculated current density. The larger error bars for the in-plane (IP) series compared to the PMA series in (A) are primarily a result of greater sample-to-sample scatter in the VSM measurements of MstCo rather than uncertainty in the Sagnac measurement.