Large spin-orbit torque observed in epitaxial SrIrO3 thin films

Semimetallic iridate compound SrIrO3 epitaxial films have been deposited by off-axis sputtering, exhibiting excellent crystalline quality as well as smooth surfaces. By performing second-harmonic Hall measurements on a series of SrIrO3/Co1-xTbx bilayers, we quantitatively determined the spin-to-charge interconversion efficiency theta(SH) of SrIrO3 and discovered a systematic temperature and film thickness dependent evolution behavior. Notably, the measured vertical bar theta(SH)vertical bar reaches a remarkably large number of similar to 1.1 at room temperature, which is significantly larger than the value of 5d transition metals and comparable to the values reported in some topological material systems. Our findings are further corroborated by ferromagnetic resonance-driven spin pumping studies in SrIrO3/Py bilayers, highlighting the significant opportunities offered by the iridate compounds in designing next-generation energy-efficient multifunctional spin Hall devices.