Direct observation of proximity-induced magnetism and spin reorientation in topological insulator on a ferrimagnetic oxide

Chao Yao Yang, Yen Hsun Lee, Kui Hon Ou Yang, Kuan Chia Chiu, Chi Tang, Yawen Liu, Yi Fan Zhao, Cui Zu Chang, Fan Hsiu Chang, Hong Ji Lin, Jing Shi, Minn Tsong Lin

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3 Scopus citations

Abstract

The quantum anomalous Hall effect (QAHE) in a magnetic topological insulator system without the need of an external magnetic field becomes of great interest because of its dissipationless spin currents. The proximity effect via a magnetic adlayer is a promising strategy to bring magnetism into a topological insulator (TI) due to its boosted Curie temperature for a realistic application. In this work, a proximity-induced magnetism above 90 K in a TI, (Bi 0.25 Sb 0.75 ) 2 Te 3 , on a ferrimagnetic adlayer with perpendicular magnetic anisotropy, thulium-iron-garnet (TIG), was evidenced directly by using magnetic circular dichroism. A competition between exchange couplings with different sublattice-sites was further revealed element-specifically in a temperature-driven spin-reorientation of TI, bringing an issue on magnetic inhomogeneity at the interface, which might cause difficulties in obtaining QAHE in such a TI/TIG bilayer system. Our results prove directly the robust magnetism of TI above liquid nitrogen temperatures and also give a deep insight into the mechanism of interfacial coupling in the proximity effect for the bilayer of TI and magnetic oxide, which could be essential for the design of a system with QAHE.

Original languageEnglish (US)
Article number082403
JournalApplied Physics Letters
Volume114
Issue number8
DOIs
StatePublished - Feb 25 2019

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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