Visualizing ferromagnetic domain behavior of magnetic topological insulator thin films
Visualizing ferromagnetic domain behavior of magnetic topological insulator thin films
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DOI：
10.1038/npjquantmats.2016.23
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发表时间：
2016-10-21
影响因子：
5.7
通讯作者：
Wu, Weida
中科院分区：
文献类型：
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作者：
Wang, Wenbo;Chang, Cui-Zu;Wu, Weida
对磁拓扑绝缘体 Sb1.89V0.11Te3 薄膜中磁畴行为的系统磁力显微镜 (MFM) 研究表明，在原始磁畴状态下，零场冷却后，出现了相同数量的上下磁畴。有趣的是，MFM 图像的冷却场依赖性表明，尽管这些薄膜在低温下的矫顽场 (H-C) 约为特斯拉，但小的冷却磁场（约 5-10 Oe）足以使薄膜显着极化。通过可视化掺杂 V 的 Sb2Te3 的 H-C 周围的磁化反转过程，我们观察到了铁磁体的典型磁畴行为，即。即，磁畴成核和磁畴壁扩展。我们的结果提供了磁性拓扑绝缘体铁磁行为的直接证据，这是强大的量子反常霍尔效应的必要条件。
A systematic magnetic force microscopy (MFM) study of domain behavior in thin films of the magnetic topological insulator Sb1.89V0.11Te3 reveals that in the virgin domain state, after zero-field cooling, an equal population of up and down domains occurs. Interestingly, the cooling field dependence of MFM images demonstrates that a small cooling magnetic field (approximately 5-10 Oe) is sufficient to significantly polarize the film despite the coercive field (H-C) for these films being on the order of a tesla at low temperature. By visualizing the magnetization reversal process around H-C of V-doped Sb2Te3, we observed a typical domain behavior of a ferromagnet, i. e., domain nucleation and domain wall propagation. Our results provide direct evidence of ferromagnetic behavior of the magnetic topological insulator, a necessary condition for a robust quantum anomalous Hall effect.