Dielectric properties and relaxation behaviors of Ba doped Sr_0.97Sm_0.02TiO₃ ceramics in different sintering atmospheres

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• 作者：Guangyao Li ; Hanxing Liu ; ^{lhxhp@whut.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Hua Hao ; Jiajia Liu ; Zhuo Chen ; Xindi Huang ; Minghe Cao ; Zhonghua Yao
• 关键词：Dielectric properties ; Giant permittivity ; Dielectric relaxation ; Oxygen vacancies
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：15 November 2016
• 年：2016
• 卷：42
• 期：15
• 页码：16782-16788
• 全文大小：2208 K

文摘

The Ba_xSr_0.97−xSm_0.02TiO₃ (x=0–0.4) ceramics in different sintering atmosphere were prepared by conventional solid-state reaction methods. The effect of different atmosphere on the dielectric properties of Ba_xSr_0.97−xSm_0.02TiO₃ ceramics was investigated. The giant permittivity was obtained for Ba_xSr_0.97−xSm_0.02TiO₃ ceramics sintered in nitrogen especially for x=0.2, which exhibited a weak temperature- and frequency- dependent giant permittivity (>10⁴) as well as a low dielectric loss (mostly <0.05) over a broad temperature range from 20 to 300 °C. Based on the relaxation behaviors, XPS Spectrum and complex- impedance analysis of ceramics in different sintering atmosphere, the giant permittivity and low dielectric loss were due to the existence of the giant defect dipoles [Ti⁴⁺·e -$V_o^{..}$- e·Ti⁴⁺] generated by the fully ionized oxygen vacancies and Ti³⁺ ions, while the defect dipoles ($V_{\mathit{Sr}}^{,,}-V_o^{..}$) and interfacial polarization caused the dielectric relaxation of the ceramics sintered in air or O₂.