High dielectric-permittivity properties of NaCu₃Ti₃Sb_0.5Nb_0.5O₁₂ ceramics

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• 作者：Yongjie Shi^b ; Wentao Hao^a ; ^b ; ^{hhhaowentao@163.com" class="auth_mail" title="E-mail the corresponding author} ; Hui Wu^b ; Li Sun^a ; ^b ; Ensi Cao^a ; ^b ; Yongjia Zhang^a ; ^b ; Hua Peng^a ; ^b
• 关键词：NaCu3Ti3Sb0.5Nb0.5O12 ceramics ; High dielectric-permittivity properties ; Internal barrier layer capacitance effect ; CaCu3Ti4O12 ceramics
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：42
• 期：1
• 页码：116-121
• 全文大小：1570 K

文摘

A series of NaCu₃Ti₃Sb_0.5Nb_0.5O₁₂ ceramics were prepared by the conventional solid-state reaction technique under different sintering temperatures. Their crystalline structures, microstructures, dielectric properties 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 sintering temperature. Those ceramics sintered above 1293 K perform high dielectric-permittivity properties with ε′ over 5000. Impedance spectroscopy analysis reveals that NaCu₃Ti₃Sb_0.5Nb_0.5O₁₂ ceramics are electrically heterogeneous and composed of semiconducting grains and insulating grain boundaries. Moreover, a small amount of CuO secondary phase and Cu²⁺/Cu¹⁺, Ti⁴⁺/Ti³⁺, Sb⁵⁺/Sb³⁺ and Nb⁵⁺/Nb⁴⁺ aliovalences is found to exist in NaCu₃Ti₃Sb_0.5Nb_0.5O₁₂ ceramics through XRD and XPS analysis. Internal barrier layer capacitance effect is suggested to be the origin of the high dielectric-permittivity properties in NaCu₃Ti₃Sb_0.5Nb_0.5O₁₂ ceramics.