Principal Investigator Jongyoon Han
Recent studies on the topological insulators (TI) have attracted great attention due to the rich spin-orbit physics and promising applications in spintronic devices. In particular, the strongly spin-moment coupled electronic states have been extensively pursued to realize efficient spin-orbit torque (SOT) switching. However, so far current-induced magnetic switching with TI has been observed only at cryogenic temperatures. Whether the topologically protected electronic states in TI could benefit from spintronic applications at room temperature remains a controversial issue.
In this work, we report SOT switching in a TI/ ferromagnet heterostructure with perpendicular magnetic anisotropy (PMA) at room temperature. Ferrimagnetic cobalt-terbium (CoTb) alloy with robust bulk PMA is directly grown on a classical TI material, Bi2Se3. The low switching current density provides definitive proof of the high SOT efficiency from TI and suggests the topological spin-momentum locking in TI even if it is neighbored by a strong ferromagnet. Furthermore, the effective spin Hall angle of TI is determined to be several times larger than commonly used heavy metals. Our results demonstrate the robustness of TI as an SOT switching material and provide an avenue towards applicable TI-based spintronic devices.