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Nb掺杂Bi4Ti3O12层状结构铁电陶瓷的电行为特性研究

张丽娜; 李国荣; 赵苏串; 郑嘹赢; 殷庆瑞   

  1. 中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室, 上海 200050
  • 收稿日期:2004-11-08 修回日期:2005-02-24 出版日期:2005-11-20 网络出版日期:2005-11-20

Electrical Behavior of Nb-doped Bi4Ti3O12 Layer-structured Ferroelectric Ceramics

ZHANG Li-Na; LI Guo-Rong; ZHAO Su-Chuan; ZHENG Liao-Ying; YIN Qing-Rui   

  1. The State Key Lab of High Performance Ceramics and Superfine Microstructure; Shanghai Institute of Ceramics; Chinese Academy of Sciences; Shanghai 200050, China
  • Received:2004-11-08 Revised:2005-02-24 Published:2005-11-20 Online:2005-11-20

摘要: 采用固相烧结工艺制备了Nb5+掺杂的Bi4Ti3O12层状结构铁电陶瓷.运用XRD 和AFM对Bi4Ti3-xNbxO12+x/2材料的微观结构进行表征,发现所制备的陶瓷均具有单一的正交相结构,抛光热腐蚀表面晶粒的显微形貌表现为随机排列的棒状结构.通过对材料直流电导率与温度关系的Arrhenius拟合,分析丁Bi4Ti3-xNbxO12+x/2的导电机理. Nb5+掺杂提高了材料的介电常数,但居里温度随掺杂含量的增加呈线性下降趋势.DSC结果显示Bi4Ti3-xNbxO12+x/2材料在居里温度处经历了一级铁电相变.样品的铁电性能测试结果表明, Nb5+掺杂Bi4Ti3O12提高了材料的剩余极化Pr,这主要是由于Nb5+取代Ti4+大大降低了材料中氧空位的浓度,使得氧空位对畴的钉扎作用减弱的缘故.

关键词: 导率, 活化能, 铁电性能, Bi4Ti3O12

Abstract: Nb5+-doped Bi4Ti3O12 layer-structured ferroelectric ceramics were prepared by the solid-state reaction technology. Microstructures of Bi4Ti3-xNbxO12+x/2 materials were characterized by XRD and SEM. The results show that Bi4Ti3-xNbxO12+x/2 material has a single orthorhombic structure. The grains of polished and thermally etched surfaces reveal a needle-like structure. Electronic conductor mechanism of Bi4Ti3-xNbxO12+x/2 was analyzed by the Arrhe-nius fit of direct current conductivity vs temperature. Dielect constants of Bi4Ti3-xNbxO12+x/2 ceramics increase by Nb5+ doping. The Curie temperatures decrease linearly with the increase of Nb5+ concedntration. DSC results show that Bi4Ti3-xNbxO12+x/2 materials undergo the firstorder ferroelectric phase transition at the Curie point. Nb5+ doping Bi4Ti3O12 ceramics results in an increase remanent polarizatgion (Pr) according to ferroelectric test results. The reason is that Nb5+ substituting for Ti4+ decreases the concentration of oxygen vacancies. The effect of oxygen vacancies on domain pinning is reduced significantly.

Key words: electrical conductivity, activation energy, ferroelectric properties, Bi4Ti3O12

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