Effect of grain-boundary behavior on the dc electric conduction in Rb-doped CaCu3Ti4O12
Effect of grain-boundary behavior on the dc electric conduction in Rb-doped CaCu3Ti4O12
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DOI：
10.1007/s10854-012-0881-8
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发表时间：
2013-03
期刊：
影响因子：
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通讯作者：
Zhi Yang;Yue Zhang;Kun Zhang;D. Yin;R. Xiong;Jing Shi
中科院分区：
文献类型：
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作者：
Zhi Yang;Yue Zhang;Kun Zhang;D. Yin;R. Xiong;Jing Shi
采用溶胶-凝胶法合成了Ca 1 − xRbxCu 3 Ti4 O 12（x= 0，0.03，0.05，0.07和0.09）陶瓷。X射线衍射、扫描电子显微镜和能量色散X射线分析结果表明，掺铷陶瓷样品中形成了少量的氧化铜和富铜贫钛成分的晶界层。采集了不同温度下直流电流密度随电场强度的变化曲线，并基于晶界肖特基模型对晶界导电行为进行了详细研究。结果表明，富铜贫钛晶界的形成对晶界肖特基势垒特性有很大影响。例如，势垒宽度随掺杂浓度x的增加而增加，势垒高度（λ B）随掺杂浓度x的减小而增大，但当x大于0.05时，λ B值减小。这是由于晶界上的第二相和电子结构的变化造成的。
Ca1−xRbxCu3Ti4O12(x= 0, 0.03, 0.05, 0.07 and 0.09) ceramics have been synthesized by the sol–gel method. The results of X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis indicate that a small amount of CuO and the grain boundary layers with Cu-rich and Ti-poor compositions are formed in the Rb-doped ceramic samples. The curves of dc electrical current density versus electric field strength have been collected at different temperatures, and the electrical conduction behaviors at grain boundary have been studied in detail based on the grain-boundary Schottky model. The results show that the formation of the Cu-rich and Ti-poor grain boundaries greatly affects the properties of grain-boundary Schottky potential barrier. For example, the barrier width increases with the increase on doping concentrationx, and the barrier height (ФB) is also greatly enhanced as the concentration of dopants is very small, but asxis larger than 0.05, the ФBvalues reduce. These results should be ascribed to the second phases at grain boundary and the change of electronic structure.