Effects of thermal annealing on the spin–orbit torque and unidirectional spin Hall magnetoresistance in Pt/CoFe/Ta trilayers

We investigated the spin–orbit torque (SOT) and unidirectional spin Hall magnetoresistance (USMR) in Pt/CoFe/Ta trilayer as well Pt/CoFe CoFe/Ta bilayers with in-plane magnetic anisotropy by performing transverse longitudinal second harmonic resistance measurements. Compared to two bilayers, we found that exhibits enhanced SOT USMR due opposite angles of Pt Ta, which work together enhance accumulation trilayer. Furthermore, thermal annealing has a significant influence on magnitude sign trilayers. Specifically, observed both damping-like decrease temperature increases, they even change signs at an between 235 265 °C. In contrast, upon is absent bilayers. These findings suggest can be easily manipulated using appropriate treatment, important implications for development novel spintronic devices.