York-Nanjing Joint Center for Spintronics and Nano Engineering (YNJC), School of Electronics Science and Engineering, Nanjing University , Nanjing 210093, China.
Nano Lett. 2015 Jan 14;15(1):764-9. doi: 10.1021/nl504480g. Epub 2014 Dec 24.
We report a study of enhancing the magnetic ordering in a model magnetically doped topological insulator (TI), Bi(2-x)Cr(x)Se(3), via the proximity effect using a high-TC ferrimagnetic insulator Y(3)Fe(5)O(12). 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 TC 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.
我们报告了一项通过使用高温铁磁绝缘体 Y(3)Fe(5)O(12)的近邻效应来增强模型磁掺杂拓扑绝缘体 (TI) Bi(2-x)Cr(x)Se(3)中磁有序的研究。FMI 为 TI 提供了交换相互作用的来源，而不会去除非平凡的表面态。通过进行元素特定的 X 射线磁圆二色性 (XMCD) 测量，我们在这种磁掺杂 TI/FMI 异质结构中明确观察到 TC 增强了 50 K。我们还发现了一个更大的（30 K 时为 6.6 nm）但更快减小的（30 K 到 50 K 减小 80%）穿透深度，与稀释铁磁半导体 (DMS) 相比，这可能表明 FMI 和非平凡 TI 表面之间相互作用的一种新机制。
