Dielectric and nonlinear current-voltage characteristics of rare-earth doped CaCu3Ti4O12 ceramics
Dielectric and nonlinear current-voltage characteristics of rare-earth doped CaCu3Ti4O12 ceramics
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稀土掺杂CaCu3Ti4O12陶瓷的介电和非线性电流-电压特性
DOI：
10.1063/1.3658258
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发表时间：
2011-11-01
影响因子：
3.2
通讯作者：
Hu, Changzheng
中科院分区：
文献类型：
--
作者：
Liu, Laijun;Fang, Liang;Hu, Changzheng
采用传统固相反应法制备了稀土氧化物（Y2 O3、La 2 O3、Eu 2 O3和Gd 2 O3）掺杂的CaCu 3 Ti4 O 12（CTO）陶瓷，研究了稀土氧化物掺杂对压敏电阻性能的影响。采用X射线衍射仪（XRD）和扫描电镜（SEM）对陶瓷的物相和形貌进行了表征。采用高压测量装置和精密阻抗分析仪分别测量了陶瓷的非欧姆（J-E）特性、介电性能和阻抗谱。结果表明，稀土氧化物显著提高了CCTO陶瓷的击穿电场，但降低了非线性系数和平均晶粒尺寸。ln J与E-1/2之间有很好的线性关系，说明肖特基势垒应该存在于晶界处。提出了一种由耗尽层和负电荷层组成的双肖特基势垒模型，类似于ZnO压敏电阻的势垒模型。由稀土离子扩散距离和有效表面态决定的耗尽层宽度对陶瓷的电性能有重要影响。(C)2011年美国物理学会。[doi：10.1063/1.3658258]
CaCu3Ti4O12 (CCTO) ceramics doped with rare earth (RE) oxides, including Y2O3, La2O3, Eu2O3, and Gd2O3, were prepared by the traditional solid-state reaction method in order to investigate the effect of RE oxide dopants on the electrical properties as a varistor. The phase identification and morphology of the ceramics were investigated by x-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. A high voltage measuring unit and precision impedance analyzer were used to determine the nonohmic (J-E) behaviors and measure the dielectric properties and impedance spectroscopy of the ceramics, respectively. The results showed that RE oxides enhanced greatly the breakdown electric flied but reduced the nonlinear coefficient and the mean grain size of CCTO ceramics. There was a good linear relationship between ln J and E-1/2, which demonstrated that the Schottky barrier should exist at the grain boundary. A double Schottky barrier model composed of a depletion layer and a negative charge sheet was proposed, analogous to the barrier model for ZnO varistors. The depletion layer width determined by diffusion distance of RE ions and the effective surface states played important roles on the electrical properties of the ceramics. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3658258]