Spin-orbit torque switching in low-damping magnetic insulators: A micrmomagnetic study

Magnetic insulators, in particular, rare-earth iron garnets, have low damping compared to metallic ferromagnetic materials due to lack of conduction electrons. In analogy to spin-transfer-torque devices, the low-damping nature is presumed to be an advantage for spintronic applications. We report that perpendicular magnetic anisotropy material with low damping actually does not favor reliable spin-orbit torque (SOT) switching. Increasing damping, introducing interfacial Dzyaloshinskii-Moriya interactions, or field-like torques may help SOT switching in some cases. Having notches in a nanometer-scale element, which is a more realistic size for practical applications, can also improve switching stability.