多铁材料BiFeO3薄膜中失配压应变导致的界面重构

多铁材料BiFeO₃薄膜中失配压应变导致的界面重构

耿皖荣^1，2，朱银莲^1*，唐云龙¹，马秀良^1，3

（1.中国科学院金属研究所沈阳材料科学国家研究中心，辽宁 沈阳110016；2.中国科学技术大学，安徽 合肥230026；3.兰州理工大学材料科学与工程学院省部共建有色金属先进加工与再利用国家重点实验室，甘肃 兰州730050）

摘要   本文利用透射电子显微术研究了外延生长的多铁BiFeO₃/NdGaO₃ (110)_O薄膜中的界面重构现象。高分辨HAADF-STEM像表明：衬底的截止层为GaO₂原子层；在BiFeO₃/NdGaO₃界面处，Nd元素部分取代了BiFeO₃的Bi元素，从而在平行于界面的第一原子层形成了BiO-NdO交替排列的界面重构形态。利用寻峰拟合方法对高分辨HAADF-STEM像的分析表明，这种界面重构的发生可以部分释放衬底施加的压应变。本研究提出了多铁材料BiFeO₃薄膜中一种新的应变释放途径。

关键词   多铁薄膜；界面重构；应变释放；扫描透射电子显微镜

中图分类号：TB383；TG115.21⁺5.3  文献标识码：A    doi:10.3969/j.issn.1000-6281.2019.06.001

The interface reconstruction induced by compressive strain in multiferroic BiFeO₃ films

GENG Wan-rong^1，2，ZHU Yin-Lian^1*，TANG Yun-Long¹，MA Xiu-Liang^1，3

(1. Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang Liaoning110016; 2. University of Science and Technology of China, Hefei Anhui 230026; 3. School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou Gansu 730050，China)

 Abstract   The interfacereconstruction in epitaxial BiFeO₃/NdGaO₃(110)_O films was analyzed by transmission electron microscopy. The atomically resolved HAADF-STEM images demonstrated that the termination of the substrate was GaO₂ layer. At the first layer of interface, the element of Nd in substrate partially substituted for the Bi element in BFO film, leading to the formation of interface reconstruction, arranged alternatively in the form of BiOcolumn and NdO column. The analyses of HAADF-STEM images with peak finding revealed that the interface reconstruction could partially release the compressive strain from substrates. These results have proposed an alternative way to release strain in multiferroic BFO films.

Keywords   multiferroic thin films；interface reconstruction; strain release；scanning transmission electron microscopy

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