Infrared spectra, Raman spectra, microwave dielectric properties and simulation for effective permittivity of temperature stable ceramics AMoO4-TiO2 (A = Ca, Sr).
Infrared spectra, Raman spectra, microwave dielectric properties and simulation for effective permittivity of temperature stable ceramics AMoO4-TiO2 (A = Ca, Sr).
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DOI：
10.1039/c2dt31878d
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发表时间：
2013-01
影响因子：
4
通讯作者：
Jing Guo;Di Zhou;Lu Wang;Hong Wang;T. Shao;Z. Qi;X. Yao
中科院分区：
文献类型：
--
作者：
Jing Guo;Di Zhou;Lu Wang;Hong Wang;T. Shao;Z. Qi;X. Yao
本文采用固相反应法制备了（1 - x）AMoO（4）-xTiO（2）（A = Ca，Sr）微波介质材料。研究了该材料的相组成、烧结行为、显微结构、微波介电性能、有效介电常数和振动声子模式。X射线衍射和扫描电子显微镜分析表明，AMoO（4）（A = Ca，Sr）相和TiO（2）相可以共存。用有限元法计算了AMoO（4）-TiO（2）复合材料的有效介电常数，并与实测值和经典混合规则的计算结果进行了比较。利用红外光谱和拉曼光谱研究了介电性能与晶体结构之间的相关性。用经典谐振子模型对红外光谱进行了分析，发现AMoO（4）（A = Ca，Sr）的外振动模式对介电常数的影响最大。拉曼光谱表明，[MoO（4）]四面体中存在强烈的相互作用，这是由于拉曼峰尖锐而强烈。在900 °C低温烧结条件下，添加3wt%H3BO3CuO（BCu），制得了介电常数ε（r）= 10.6 ~ 13、Q×f值（40700 ~ 72050 GHz）、谐振频率温度系数（TCF或τ（f）值）接近于零的微波介质陶瓷。这些结果也表明（1 - x）AMoO（4）-xTiO（2）-BCu（A = Ca，Sr）陶瓷是一种很好的微波电子器件应用候选材料。
In this work, temperature stable microwave dielectric materials (1 - x)AMoO(4)-xTiO(2) (A = Ca, Sr) were prepared by a solid state reaction method. The phase composition, sintering behaviors, microstructures, microwave dielectric properties, effective permittivity and vibrational phonon modes were investigated. The X-ray diffraction pattern and scanning electron microscope analysis indicated that the AMoO(4) (A = Ca, Sr) phase could coexist with the TiO(2) phase. The effective dielectric constants of the AMoO(4)-TiO(2) composites were calculated by the finite element method (FEM), compared with the measured values and the numerical results obtained by the classical mixing rules. The correlation between the dielectric properties and the crystal structures were studied using IR and Raman spectroscopy. The infrared spectra were analyzed using the classical harmonic oscillator model, and revealed that the external vibration modes of AMoO(4) (A = Ca, Sr) had the most significant influence on the dielectric constant. The Raman spectra showed that there were strong interactions in the [MoO(4)] tetrahedron due to the sharp and intense Raman modes. Finally, the low-firing (900 °C) microwave dielectric ceramics were obtained with 3 wt% H(3)BO(3)-CuO addition (BCu), and they possess good microwave dielectric properties with ε(r) = 10.6-13, high Q×f values (40 700-72 050 GHz), and near-zero temperature coefficients of resonant frequency (TCF or τ(f) values). These results also show that (1 - x)AMoO(4)-xTiO(2)-BCu (A = Ca, Sr) ceramics are good candidates for microwave electronic device applications.