(Ba_(0.8)Sr_(0.2))_(1-1.5x)Bi_xTiO_3陶瓷的弥散相变和高温介电异常研究  

Diffuse Phase Transition and High-temperature Dielectric Anomaly of (Ba_(0.8)Sr_(0.2))_(1-1.5x)Bi_xTiO_3 Ceramics

作　　者：陈锋[1] 刘秋香[1] 

机构地区：[1]广东工业大学物理与光电工程学院,广东广州510006

出　　处：《广东工业大学学报》2016年第5期69-76,共8页Journal of Guangdong University of Technology

基　　金：国家自然科学基金资助项目(10774030;11032010;11202054);广东省高教基金资助项目(2012KJCX0044)

摘　　要：采用传统固相法制备(Ba_(0.8)Sr_(0.2))_(1-1.5x)Bi_xTiO_3(x=0.02,0.05,0.15,缩写为BSBT)陶瓷.在空气条件下1 473 K保温2 h退火制得,并对陶瓷样品的结构、微观形貌和介电性能进行了测试.其中,在介电研究中不仅出现了弥散的相变,并且在高温区域观察到了弥散型的介电异常.根据居里-外斯定律的拟合结果,在样品x=0.05的BSBT陶瓷样品中出现相对较强的一个弥散相变.此外,通过阻抗分析,不仅表征了BSBT陶瓷的晶界电阻,还由此算出陶瓷样品的活化能和电导活化能.极化原理表明BSBT陶瓷的高温弛豫与氧空位引起离子的跳跃有关.而对于样品的高温介电异常,此处认为是一种介电弛豫行为,主要由弛豫强度变化所致.（ Ba0.8Sr0.2）1- 1.5x,BixTiO3（x ｜ = 0. 02 ,0. 05 ,0. 15 , short for BSBT） ceramics were synthesized by the traditional solid state reaction method. Sintering was done at 1473 K for 2 h in air atmosphere. The structural, microstructure and dielectric properties of ceramics were investigated, in which a diffuse phase transition was exhibited in dielectric studies and a diffuse dielectric anomaly was observed in high temperature range. According to the fitting results of Curie-Weiss law, BSBTceramics exhibited a stronger phase transition for x =0. 05. Besides, grain boundary resistivity of BSBT ceramics was characterized by an impedance analysis and activation energy and the activation energy for conduction calculated. Polaron theory indicated that the relaxation in BSBT ceramics at high temperatures was associated with the hopping ions caused by oxygen vacancies. And it is suggested that the diffuse dielectric anomaly for all samples was due to a competition between the dielectric relaxation behavior and the variation of the relax-ation strength.

关 键 词：(Ba0.8Sr0.2)1-1.5xBixTiO3陶瓷 弥散相变 介电异常 氧空位 

分 类 号：O472[理学—半导体物理]