PT  - JOURNAL ARTICLE
AU  - Li, Peng
AU  - Kally, James
AU  - Zhang, Steven S.-L.
AU  - Pillsbury, Timothy
AU  - Ding, Jinjun
AU  - Csaba, Gyorgy
AU  - Ding, Junjia
AU  - Jiang, J. S.
AU  - Liu, Yunzhi
AU  - Sinclair, Robert
AU  - Bi, Chong
AU  - DeMann, August
AU  - Rimal, Gaurab
AU  - Zhang, Wei
AU  - Field, Stuart B.
AU  - Tang, Jinke
AU  - Wang, Weigang
AU  - Heinonen, Olle G.
AU  - Novosad, Valentine
AU  - Hoffmann, Axel
AU  - Samarth, Nitin
AU  - Wu, Mingzhong
TI  - Magnetization switching using topological surface states
AID  - 10.1126/sciadv.aaw3415
DP  - 2019 Aug 01
TA  - Science Advances
PG  - eaaw3415
VI  - 5
IP  - 8
4099  - http://advances.sciencemag.org/content/5/8/eaaw3415.short
4100  - http://advances.sciencemag.org/content/5/8/eaaw3415.full
SO  - Sci Adv2019 Aug 01; 5
AB  - Topological surface states (TSSs) in a topological insulator are expected to be able to produce a spin-orbit torque that can switch a neighboring ferromagnet. This effect may be absent if the ferromagnet is conductive because it can completely suppress the TSSs, but it should be present if the ferromagnet is insulating. This study reports TSS-induced switching in a bilayer consisting of a topological insulator Bi2Se3 and an insulating ferromagnet BaFe12O19. A charge current in Bi2Se3 can switch the magnetization in BaFe12O19 up and down. When the magnetization is switched by a field, a current in Bi2Se3 can reduce the switching field by ~4000 Oe. The switching efficiency at 3 K is 300 times higher than at room temperature; it is ~30 times higher than in Pt/BaFe12O19. These strong effects originate from the presence of more pronounced TSSs at low temperatures due to enhanced surface conductivity and reduced bulk conductivity.