Frequency and temperature dependent dielectric and conductivity behavior of 0.95(K0.5Na0.5)NbO3-0.05BaTiO3 ceramic
Frequency and temperature dependent dielectric and conductivity behavior of 0.95(K0.5Na0.5)NbO3-0.05BaTiO3 ceramic
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DOI：
10.1016/j.matchemphys.2010.12.046
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发表时间：
2011-04-15
影响因子：
4.6
通讯作者：
Hu, Changzheng
中科院分区：
文献类型：
--
作者：
Liu, Laijun;Wu, Meixia;Hu, Changzheng
对0.95（K0.5Na0.5）NbO 3 -0.05BaTiO（3）（KNN-5 BT）陶瓷进行了介电和电导率测量，测量结果均为温度（类似于350-850 K）和频率（40 Hz至100 MHz）的函数。在居里温度以上（约590 K）观察到了高温介电弛豫现象，并用Cole-Cole函数进行了分析。频率依赖的电导率进行了分析与扩展Jonscher关系，并表现出普遍的电导率行为。介电弛豫的激活能估计为1.09 eV。这可能是由于双电离氧空位的热运动或受主离子与电荷补偿氧空位之间形成缺陷偶极子所致。基于Ba ~（2+）和Ti ~（4+）离子掺入KNN晶格位置的可能模式，提出了高温介电弛豫和频率依赖电导率的机制。(C)2010 Elsevier B. V.保留所有权利。
Dielectric and conductivity measurements were carried out on the 0.95(K0.5Na0.5)NbO3-0.05BaTiO(3) (KNN-5BT) ceramic both as a function of temperature (similar to 350-850 K) and frequency (40 Hz to 100 MHz). A high-temperature dielectric relaxation above Curie temperature (similar to 590 K) was observed and analyzed with the Cole-Cole function. Frequency dependent conductivity was analyzed with an augmented Jonscher relation and exhibited a universal conductivity behavior. The activation energy of dielectric relaxation was estimated to be 1.09 eV. It could be attributed to the thermal motion of double ionized oxygen vacancy or to the formation of defect dipoles between the acceptor ion and charge compensating oxygen vacancies. The mechanism for both the high-temperature dielectric relaxation and the frequency dependent conductivity was proposed based on a possible mode of incorporation of Ba2+ and Ti4+ ions into the KNN lattice sites. (C) 2010 Elsevier B.V. All rights reserved.