Magnetic proximity coupling to Cr-doped Sb2Te3 thin films

Article

关键词: 3-DIMENSIONAL TOPOLOGICAL INSULATOR;    CIRCULAR-DICHROISM;    ABSORPTION-SPECTRA;    FERROMAGNETISM;    TRANSITION;    ANISOTROPY;    CRITERION;    STATE;   

DOI  :  10.1103/PhysRevB.95.224422

来源: SCIE

【 摘 要 】

Using soft x-ray absorption spectroscopy we determined the chemical and magnetic properties of the magnetic topological insulator (MTI) Cr:Sb2Te3. X-ray magnetic circular dichroism (XMCD) at the Cr L-2,L-3, Te M-4,M-5, and Sb M-4,M-5 edges shows that the Te 5p moment is aligned antiparallel to both the Cr 3d and Sb 5p moments, which is characteristic for carrier-mediated ferromagnetic coupling. Comparison of the Cr L-2,L-3 spectra with multiplet calculations indicates a hybridized Cr state, consistent with the carrier-mediated coupling scenario. We studied the enhancement of the Curie temperature, T-C, of the MTI thin film through the magnetic proximity effect. Arrott plots, measured using the Cr L-3 XMCD, show a T-C approximate to 87 K for the as-cleaved film. After deposition of a thin layer of ferromagnetic Co onto the surface, the T-C increases to similar to 93 K, while the Co and Cr moments are parallel. This increase in T-C is unexpectedly small compared to similar systems reported earlier. The XMCD spectra demonstrate that the Co/MTI interface remains intact, i.e., no reaction between Co and the MTI takes place. Our results are a useful starting point for refining the physical models of Cr-doped Sb2Te3, which is required for making use of them in device applications.

【 授权许可】

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