Enhancing Magnetic Ordering in Cr-Doped Bi2Se3 Using High-TC Ferrimagnetic Insulator

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• 作者：Wenqing Liu ; Liang He ; Yongbing Xu ; Koichi Murata ; Mehmet C. Onbasli ; Murong Lang ; Nick J. Maltby ; Shunpu Li ; Xuefeng Wang ; Caroline A. Ross ; Peter Bencok ; Gerrit van der Laan ; Rong Zhang ; Kang. L. Wang
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：January 14, 2015
• 年：2015
• 卷：15
• 期：1
• 页码：764-769
• 全文大小：370K
• ISSN：1530-6992

文摘

We report a study of enhancing the magnetic ordering in a model magnetically doped topological insulator (TI), Bi_2鈥?i>xCr_xSe₃, via the proximity effect using a high-T_C ferrimagnetic insulator Y₃Fe₅O₁₂. The FMI provides the TI with a source of exchange interaction yet without removing the nontrivial surface state. By performing the elemental specific X-ray magnetic circular dichroism (XMCD) measurements, we have unequivocally observed an enhanced T_C of 50 K in this magnetically doped TI/FMI heterostructure. We have also found a larger (6.6 nm at 30 K) but faster decreasing (by 80% from 30 to 50 K) penetration depth compared to that of diluted ferromagnetic semiconductors (DMSs), which could indicate a novel mechanism for the interaction between FMIs and the nontrivial TIs surface.