New 8-Layer Twinned Hexagonal Perovskite Microwave Dielectric Ceramics Ba8Ga4–xTa4+0.6xO24
New 8-Layer Twinned Hexagonal Perovskite Microwave Dielectric Ceramics Ba8Ga4–xTa4+0.6xO24
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DOI：
10.1021/cm2025944
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发表时间：
2011-10
影响因子：
8.6
通讯作者：
Jiang Cao;X. Kuang;M. Allix;C. Dickinson;J. Claridge;M. Rosseinsky;D. Iddles;Q. Su
中科院分区：
文献类型：
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作者：
Jiang Cao;X. Kuang;M. Allix;C. Dickinson;J. Claridge;M. Rosseinsky;D. Iddles;Q. Su
合成了八层B位缺陷孪晶六方钙钛矿Ba 8 Ga 4-xTa 4 + 0.6xO 24，并对其结构和微波介电性能进行了表征。这种六方钙钛矿由八个紧密堆积的BaO 3层组成，这些层按（ccch）2的顺序堆叠，其中c和h分别指立方和六方BaO 3层。Ba 8 Ga 4-xTa 4 +0.6xO24陶瓷材料具有与组分无关的介电常数ε r = 29，Qf值随B位空位含量的增加而提高，谐振频率温度系数τf由负到正可调。Ba8Ga0.8Ta5.92O24：Qf = 29 000 GHz，τf = 11 ppm/°C时微波介电性能最佳。通过与8层孪晶类似物和相关的10层孪晶六方钙钛矿的结构和性能数据的比较，讨论了控制微波介电性能的因素。
An 8-layer B-site deficient twinned hexagonal perovskite Ba8Ga4–xTa4+0.6xO24 has been synthesized and its structure and microwave dielectric properties characterized. This hexagonal perovskite consists of eight close-packed BaO3 layers stacked by a sequence of (ccch)2, where c and h refer to cubic and hexagonal BaO3 layers, respectively. The Ba8Ga4–xTa4+0.6xO24 ceramic materials exhibit composition-independent dielectric permittivity er ≈ 29, improved Qf value with the B-site vacancy content increase, and tunable temperature coefficient of resonant frequency τf from negative to positive. An optimum microwave dielectric performance was achieved for Ba8Ga0.8Ta5.92O24: Qf ≈ 29 000 GHz and τf ≈ 11 ppm/°C. The factors controlling the microwave dielectric properties are discussed in comparison with 8-layer twinned analogues and related 10-layer twinned hexagonal perovskites based on their structural and property data.