Bulk and grain boundary conductivity of Ca0.97Ti1-xFexO3-δ materials
Bulk and grain boundary conductivity of Ca0.97Ti1-xFexO3-δ materials
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DOI：
10.1016/s0167-2738(03)00151-6
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发表时间：
2003-05-01
影响因子：
3.2
通讯作者：
Frade, JR
中科院分区：
文献类型：
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作者：
Chinarro, E;Jurado, JR;Frade, JR
采用常规陶瓷法制备了x = 0、0.01、0.035、0.07和0.15的ca0.97 ti1 - xfexo3 - δ多晶样品，并用阻抗谱在空气中不同温度下进行了表征。低铁含量（x < 0.05）样品的光谱清楚地显示了两个分离的体和晶界贡献，用于确定相应的电导率。虽然这些样品的体积电导率随着铁的添加而略有增加，但除了微观结构的影响（如晶粒尺寸的差异）外，发现真正的晶界电导率几乎与铁的含量无关。估计了晶界层厚度。对于铁含量为7%或更高的样品，阻抗谱显示了单一的贡献归因于体，这表明晶界电阻非常低，从而揭示了相对于铁含量低的样品，晶界行为发生了重大变化。(C) 2003 Elsevier Science B.V.版权所有
Polycrystalline Ca0.97Ti1-xFexO3-delta samples with x = 0, 0.01, 0.035, 0.07 and 0.15 were prepared by a conventional ceramic route and characterised by impedance spectroscopy at different temperatures in air. Spectra obtained for samples with low iron contents (x < 0.05) clearly show two separated bulk and grain boundary contributions, which were used to determine the corresponding conductivities. Though the bulk conductivity of those samples increases slightly with additions of Fe, the true grain boundary conductivity was found nearly independent of the content of Fe, except for effects of microstructure, such as differences in grain size. The grain boundary layer thickness was also estimated. The impedance spectra obtained for samples with Fe contents of 7% or higher show a single contribution attributed to the bulk suggesting a very low grain boundary resistance, and thus revealing a major change in grain boundary behaviour relative to samples with small Fe contents. (C) 2003 Elsevier Science B.V. All rights reserved.