Surface agglomeration is beneficial for release of magnetic property via research of rare earth (RE) element-substitution
Surface agglomeration is beneficial for release of magnetic property via research of rare earth (RE) element-substitution
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DOI：
10.1016/j.apsusc.2017.08.083
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发表时间：
2018-01-01
影响因子：
6.7
通讯作者：
Yang, Jinghai
中科院分区：
文献类型：
--
作者：
Liu, Yanqing;Qi, Ji;Yang, Jinghai
采用溶胶-凝胶法在硅衬底上成功制备了BiFeO(BFO)薄膜和稀土元素替代薄膜。在Bi位进行RE(La，Ho，Er)取代后，BFO的多铁性得到显著改善。稀土取代原理如图1(离子匹配的模拟图像)所示。通过表面和截面X射线衍射谱的全图形拟合，确定了BFO和RE替代薄膜的单相和具有R3c空间群的钙钛矿基菱面体结构。FESEM分析表明，稀土替代膜有明显的团聚现象，原子力显微镜图像显示，稀土替代膜的表面织构比BFO更平整。稀土替代膜具有较高的饱和磁化强度(Ms)和剩余磁化强度(Mr)，这是由于缺陷浓度降低(氧空位)、稀土离子半径较小(尺寸效应)和表面结构致密所致。Fe3+和O2-离子在超交换作用中起着至关重要的作用，XPS、表面和垂直EDS图像显示Fe3+和O2-离子有增加的趋势。(C)2017爱思唯尔B.V.保留所有权利。
BiFeO3 (BFO) thin films and Rare-Earth (RE) element substitutions were successfully fabricated on silicon substrates by sol-gel technology. Multiferroic properties of BFO had been improved considerably on RE (La, Ho, Er)-substitution at Bi site. The RE-substitution principle was presented in Fig. 1(the simulative images of ions matching). The single phase and the perovskite based rhombohedral structure with R3c space group of BFO and RE-substitution films were confirmed through the full pattern fitting of surface and section XRD profiles. There were obvious agglomeration phenomena for RE-substitution films via FESEM patterns, and the AFM images shown that the RE-substation films possessed smoother surface texture comparing with the BFO. The RE-substitution films showed higher saturation magnetization (Ms) and remanent magnetization (Mr) due to the reduced concentration of defects (oxygen vacancy), RE ions with smaller radii size (size effect) and surface structure of compactness. Fe3+ and O2- ions play an essential role in superexchange interaction, the XPS, surface and vertical EDS images revealed increasing tendency of Fe3+ ions and O2- ions. (C) 2017 Elsevier B.V. All rights reserved.