The strongly spin-momentum coupled electronic states in topological insulators (TI) have been extensively pursued to realize efficient magnetic switching. However, previous studies show a large discrepancy of the charge-spin conversion efficiency. Moreover, current-induced magnetic switching with TI can only be observed at cryogenic temperatures. We report spin-orbit torque switching in a TI-ferrimagnet heterostructure with perpendicular magnetic anisotropy at room temperature. The obtained effective spin Hall angle of TI is substantially larger than the previously studied heavy metals. Our results demonstrate robust charge-spin conversion in TI and provide a direct avenue towards applicable TI-based spintronic devices.
The broad impact of the sponsored research include results from the following outreach programs: 1) Undergraduate students have been engaged in the proposed research. Stephanie Bauman (from South Florida University), through CMSE REU program, got the opportunity of doing cutting-edge research on topics of nanofabrication and device engineering through this program (see image on right). 2) The PI and his students have maintained close relationships with the microelectronics industry. Since the start of the program, the PI has visited and given onsite or online seminars to companies of Intel, IBM, global foundry, Raythoen BBN, etc. This greatly improves our understanding of industry needs and facilitates future technology transfer.
Han, J., Richardella, A., Siddiqui, S.A., Finley, J., Samarth, N. and Liu, L. “Room-temperature spin-orbit torque switching induced by a topological insulator." Physical Review Letters, 119: 077702, 2017.