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首页> 外文期刊>Crystal growth & design >Growth of Nanocrystalline CaCu3Ti4O12 Ceramic by the Microwave Flash Combustion Method: Structural and Impedance Spectroscopic Studies
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Growth of Nanocrystalline CaCu3Ti4O12 Ceramic by the Microwave Flash Combustion Method: Structural and Impedance Spectroscopic Studies

机译：微波闪光燃烧法生长CaCu3Ti4O12纳米晶陶瓷的结构和阻抗谱研究

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摘要

Nanocrystalline CaCu3Ti4O12 ceramic powders of particle size ranging from 50 to 70 nm have been grown for the first time by the microwave flash combustion method. The structural and compositional properties of powders and sintered pellets are analyzed by X-ray diffraction, high-resolution transmission electon microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The dielectric properties are measured in the frequency range of 10 Hz to 8 MHz at temperatures 20-140 degrees C. Impedance spectroscopic studies reveal that the resistance of the grain and the grain boundary are 40 Omega and 8 M Omega, respectively. It is further observed that on increasing the measurement temperature, the decrease in the grain boundary resistance is relatively higher as compared to grain resistance. Simultaneously, the value tan delta at low frequencies (<2 kHz) increases exponentially with an increase in measurement temperatures (>80 degrees C). These losses are attributed to the thermally activated grain boundary electrical conduction due to copper segregation at the grain boundary. The activation energy for charge conduction is calculated to be 0.776 eV.
机译：通过微波快速燃烧方法首次生长了粒径为50至70 nm的纳米晶CaCu3Ti4O12陶瓷粉末。通过X射线衍射，高分辨率透射电子显微镜，扫描电子显微镜和能量色散X射线光谱分析了粉末和烧结颗粒的结构和组成特性。在20-140摄氏度的温度下，在10 Hz至8 MHz的频率范围内测量介电性能。阻抗谱研究表明，晶粒的电阻和晶界的电阻分别为40Ω和8 MΩ。进一步观察到，在增加测量温度时，与晶界电阻相比，晶界电阻的降低相对较高。同时，低频（<2 kHz）下的tanδ值随测量温度（> 80摄氏度）的增加呈指数增加。这些损失归因于由于在晶界处的铜偏析而引起的热活化的晶界导电。计算出的用于电荷传导的活化能为0.776 eV。

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