| Summary: | 碩士 === 國立臺灣大學 === 物理學研究所 === 105 === The magnetic topological insulator (TI) is regarded as a key to turn on quantum anomalous Hall effect (Q-AHE) as a result of the time-reversal irreversibility driven by the spontaneous magnetization. Although magnetic proximity effect is one of the best methods to magnetize TI, the research is still limited by the property of ferromagnetic layers. Recently, a novel perpendicular anisotropy ferromagnetic insulator: TIG has been manufactured and also considered as the best candidate to induce Q-AHE. This work aims at investigating the magnetic proximity effect concerning the correlation among magnetism and the electronic structure in a topological insulator heterojunctioned with a TIG ferromagnet, which is denoted TI-TIG. By utilizing the combined x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD), that enables an element-specific probe to realize the mechanism of magnetic proximity effect in giving rise to the exchange coupling between the two layers. TIG featured the perpendicular magnetic anisotropy and strong coecivity in low temperature. XMCD-like asymmetry was performed at Te M 4,5 -edges at 20K in TI, and antiferromagnetic coupling between Te and Fe^tet was also performed. Thanks to the excellent capability of x-ray technique, we hope to have a better understanding on this TI-TIG system in relation to its spintronic application.
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