Evolution of microstructure and dielectric properties of (LiCe)-doped Na_0.5Bi_2.5Nb₂O₉ Aurivillius type ceramics

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• 作者：Zhihang Peng ; Qiang Chen ; Dan Liu ; Yadan Wang ; Dinquan Xiao ; Jianguo Zhu
• 关键词：Aurivillius-type ceramics ; Dielectric relaxation ; Electrical properties ; Impedance ; Oxygen vacancies
• 刊名：Current Applied Physics
• 出版年：2013
• 出版时间：September, 2013
• 年：2013
• 卷：13
• 期：7
• 页码：1183-1187
• 全文大小：1628 K

文摘

Aurivillius type (NaBi)_0.5?x(LiCe)_xBi₂Nb₂O₉ ceramics were prepared by the standard ceramics route. The single crystal structural ceramics were achieved for all compositions and lattice distortion was decreased by (LiCe) dopants. The temperature dependent dielectric properties revealed that all compositions possess a high Curie-temperature (>780?¡ãC). A modified Curie-Weiss relationship is used to study the diffuseness behavior of a ferroelectric phase transition indicating the degree of diffuseness of NBN-based ceramics increased with (LiCe) modifications. The degradation of resistance implied a plausible model that Ce⁴⁺ ions entered into the B-site of the pseudo-perovskite structure and acted as acceptor doping. Further investigation demonstrated that both electrical conduction and dielectric relaxation processes were associated with the oxygen vacancies produced by the substitution of Nb⁵⁺ ions by the Ce⁴⁺ ions.