Dielectric Properties in the Microwave Range of K_0.5Na_0.5NbO₃ Ceramics

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• 作者：Lu Gao ; Wancheng Zhou ; Fa Luo ; Dongmei Zhu
• 关键词：Dielectric properties ; potassium sodium niobate ceramic ; microwave absorption ; oxygen vacancies
• 刊名：Journal of Electronic Materials
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：46
• 期：1
• 页码：123-129
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Optical and Electronic Materials; Characterization and Evaluation of Materials; Electronics and Microelectronics, Instrumentation; Solid State Physics;
• 出版者：Springer US
• ISSN：1543-186X
• 卷排序：46

文摘

Dielectric properties of a potassium sodium niobate (KNN) system in the microwave range up to GHz have rarely been studied. Since K_0.5Na_0.5NbO₃ is the most common and typical type of KNN materials, non-doped K_0.5Na_0.5NbO₃ ceramics were synthesized at different temperatures (1080°C, 1090°C, 1100°C, and 1110°C) by a traditional solid reaction method for further characterization and analysis. The ceramics were in perovskite phase with orthorhombic symmetry. A small quantity of second phase was found in the 1110°C sintered specimen, which resulted from the volatilization of alkali oxides as the temperature increased. The complex permittivity was measured for the first time in the microwave range (8.2–12.4 GHz) and in the temperature range from 100°C to 220°C, and the effects of annealing on the dielectric properties were studied. The results indicate that the complex permittivity of KNN ceramics over the microwave range increases mainly due to high bulk density and the additional dielectric contributions of oxygen vacancies at high temperature.