2017 User Research Highlights
2017 User Research Highlights

What Has Been Achieved:

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.

Importance of Achievement:

Our results demonstrate robust charge-spin conversion in TI and provide a direct avenue towards applicable TI-based spintronic devices.

Unique Features of the MIP That Enabled Project:

MBE growth of high quality topological insulator thin films on GaAs substrates.
Room-temperature spin-orbit torque switching induced by a topological insulator. (A) Schematic of the spin-orbit torque in Bi2Se3/CoTb heterostructure. The spins injected from Bi2Se3 to CoTb exert a torque onto the magnetic moments, which leads to magnetic switching. (B) Room temperature current-induced magnetic switching in Bi2Se3/CoTb. (C) Spin-orbit torque efficiency as a function of the in-plane magnetic field in Bi2Se3/CoTb. (D) Comparison of the effective spin Hall angles of (Bi,Sb)2Te3, Bi2Se3, Pt, and Ta measured by our experiments. TI shows much larger charge-to-spin conversion efficiency.

Credits/Names: Han, J., Richardella, A., Siddiqui, S.A., Finley, J., Samarth, N. and Liu, L. (2017) Room-temperature spin-orbit torque switching induced by a topological insulator. Phys. Rev. Lett. 119, 077702.

Download PDF Version: RoomTemperatureSpinOrbitTorqueSwitching.pdf

Year of Research Highlight: 2017

Select a Highlight Type: User Highlight