Magnetic Memories with Topological Insulator and Compensated Ferrimagnet

Speaker: Prof. Luqiao Liu
Affiliation: Massachusetts Institute of Technology


New materials and physics mechanisms are required to further lower down the power consumption and increase the switching speed of magnetic memory devices. In this talk, I will focus on two novel material systems which can provide new opportunities for magnetic switching. First, I will discuss our recent study on compensated ferrimagnetic alloys which have antiferromagnetically coupled sublattices, low magnetic moment and fast switching dynamics. Particularly, I will show that efficient electrical reading and writing can be realized in those thin films with zero magnetic moment [1, 2]. Moreover, via studying the current induced domain wall motion, we demonstrate the speed advantage associated with those materials [3]. Second, topological insulators have spin momentum locked surface states.  In our experiment, we observe current induced magnetic switchings in topological insulator/magnet bilayer films at room temperature. The large spin torque efficiency makes topological insulators outstanding candidates for realizing power efficient magnetic switching devices [4].


[1] J. Finley, et al, Physical Review Applied, 6, 054001 (2016)

[2] J. Finley, et al, Spin orbit torque switching in compensated Heulser Alloy, submitted (2018)

[3] S. Siddiqui, et al, Current-induced domain wall motion in compensated ferrimagnet, submitted (2018)

[4] J. Han, et al, Physical Review Letters, 119, 077702 (2017)


Luqiao Liu is an Assistant Professor of Electrical Engineering at the Massachusetts Institute of Technology since September 2015. He received his Ph.D. degree in Applied Physics from Cornell University in 2012.  He spent three years as a Research Staff Member at the IBM Watson Research Center before joining the MIT faculty. Luqiao’s  current research focus is on advancing new materials and novel device structures for spintronics, including spin-based memory, logic and communication applications. Luqiao Liu is the recipient of William L. McMillan Award, NSF Career Award and International Union of Pure and Applied Physics Young Scientist Award.

For more information, contact Prof. Kang Wang ()


Date(s) - Jun 13, 2018
4:00 pm - 5:00 pm

EE-IV Shannon Room #54-134
420 Westwood Plaza - 5th Flr., Los Angeles CA 90095