Tunable dielectric properties of BaZr_0.2Ti_0.8O₃–Mg₂SiO₄–MgO composite ceramics

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• 作者：Yanyan He ; Yebin Xu ; Ting Liu ; Chunlian Zeng ; Wanping Chen
• 关键词：Ceramics ; Ferroelectrics ; Oxide materials ; BaZr_xTi₁₋ ; xO₃ ; Composite ; Tunability
• 刊名：Journal of Alloys and Compounds
• 出版年：2011
• 出版时间：21 January 2011
• 年：2011
• 卷：509
• 期：3
• 页码：904-908
• 全文大小：1419 K

文摘

BaZr_0.2Ti_0.8O₃–Mg₂SiO₄–MgO composites were prepared by a solid-state reaction method, and their dielectric and tunable characteristics were investigated for the potential application as microwave tunable materials. It is observed that the addition of Mg₂SiO₄–MgO into BaZr_0.2Ti_0.8O₃ form ferroelectric (BaZr_0.2Ti_0.8O₃)–dielectric (Mg₂SiO₄–MgO) composites. The dielectric constant and loss tangent of BaZr_0.2Ti_0.8O₃–Mg₂SiO₄–MgO composites have been reduced and the overall tunability is maintained at a sufficiently high level. An anomalous relation between dielectric constant and tunability was observed: with the increase of Mg₂SiO₄ content (>30 wt % ), the dielectric constant of composite decreases and the tunability increases. The anomalous increased tunability can be attributed to redistribution of the electric field. BaZr_0.2Ti_0.8O₃–Mg₂SiO₄–MgO composites have tunability of 14.2–17.9 % at 100 kHz under 2 kV/mm, indicating that it is a promising candidate material for tunable microwave applications requiring low dielectric constant.