Above 400-K robust perpendicular ferromagnetic phase in a topological insulator

The quantum anomalous Hall effect (QAHE) that emerges under broken time-reversal symmetry in topological insulators (TIs) exhibits many fascinating physical properties for potential applications in nanoelectronics and spintronics. However, in transition metal-doped TIs, the only experimentally demon...

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Bibliographic Details
Published in:Science advances 2017-06, Vol.3 (6), p.e1700307-e1700307
Main Authors: Tang, Chi, Chang, Cui-Zu, Zhao, Gejian, Liu, Yawen, Jiang, Zilong, Liu, Chao-Xing, McCartney, Martha R, Smith, David J, Chen, Tingyong, Moodera, Jagadeesh S, Shi, Jing
Format: Article
Language:English
Subjects:
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
Materials Science
phonons
SciAdv r-articles
spin dynamics
spintronics
thermal conductivity
thermoelectric
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Summary:The quantum anomalous Hall effect (QAHE) that emerges under broken time-reversal symmetry in topological insulators (TIs) exhibits many fascinating physical properties for potential applications in nanoelectronics and spintronics. However, in transition metal-doped TIs, the only experimentally demonstrated QAHE system to date, the QAHE is lost at practically relevant temperatures. This constraint is imposed by the relatively low Curie temperature ( ) and inherent spin disorder associated with the random magnetic dopants. We demonstrate drastically enhanced by exchange coupling TIs to Tm Fe O , a high- magnetic insulator with perpendicular magnetic anisotropy. Signatures showing that the TI surface states acquire robust ferromagnetism are revealed by distinct squared anomalous Hall hysteresis loops at 400 K. Point-contact Andreev reflection spectroscopy confirms that the TI surface is spin-polarized. The greatly enhanced , absence of spin disorder, and perpendicular anisotropy are all essential to the occurrence of the QAHE at high temperatures.
ISSN:2375-2548
2375-2548
DOI:10.1126/sciadv.1700307