Spin-orbit torque generation in bilayers composed of CoFeB and epitaxial SrIrO3 grown on an orthorhombic DyScO3 substrate

We report on the highly efficient spin-orbit torque (SOT) generation in epitaxial SrIrO3 (SIO), which is grown on an orthorhombic DyScO3(110) substrate. By conducting harmonic Hall measurement in Co20Fe60B20 (CoFeB)/SIO bilayers, we characterize two kinds of the SOTs, i.e., dampinglike (DL) and fieldlike ones to find that the former is much larger than the latter. By comparison with the Pt control sample with the same CoFeB thickness, the observed DL SOT efficiency xi(DL) of SIO (similar to 0.32) is three times higher than that of Pt (similar to 0.093). The xi(DL) is nearly constant as a function of the CoFeB thickness, suggesting that the SIO plays a crucial role in the large SOT generation. These results on the CoFeB/SIO bilayers highlight that the epitaxial SIO is promising for low-current and reliable spin-orbit torque-controlled devices.