Influence of Sb-doping on dielectric properties of NaCu₃Ti₃TaO₁₂ ceramics and relevant mechanism(s)

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• 作者：Wentao Hao^a ; ^b ; ^{hhhaowentao@163.com} ; Hui Wu^b ; Panpan Xu^c ; Yongjie Shi^b ; Shuai Yang^b ; Mingwen Wang^b ; Li Sun^a ; ^b ; Ensi Cao^a ; ^b ; Yongjia Zhang^a ; ^b
• 关键词：NaCu3Ti3Ta1&minus ; xSbxO12 ceramics ; Dielectric properties ; Aliovalences ; IBLC
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：43
• 期：4
• 页码：3631-3638
• 全文大小：1842 K
• 卷排序：43

文摘

A series of NaCu3Ti3Ta1−xSbxO12 ceramics were prepared by the conventional solid-state reaction technique, and their dielectric properties, crystalline structures, microstructures and complex impedance were investigated systematically. All the ceramics show the main phases of perovskite-related crystallographic structure, and their dielectric properties change significantly with the increasing Sb-doping. All these ceramics exhibit giant dielectric-permittivity properties, and impedance spectroscopy analysis reveals that NaCu3Ti3Ta1−xSbxO12 ceramics are electrically heterogeneous and composed of insulating grain boundaries and semiconducting grains. Moreover, CuO secondary phase and Cu2+/Cu1+, Ti4+/Ti3+, Sb5+/Sb3+ and Ta5+/Ta3+ aliovalences are found to exist in NaCu3Ti3Ta1−xSbxO12 ceramics through XRD, EDS and XPS analysis. Therefore, CuO segregation and aliovalences of metal ions were suggested to contribute greatly to the internal barrier layer capacitance effect formation in NaCu3Ti3Ta1−xSbxO12 ceramics. Furthermore, Sb-doping could decrease the tanδ of NaCu3Ti3Ta1−xSbxO12 ceramics at low frequencies, and the reason was discussed.