Abstract The novel microwave dielectric ceramic EuNbO4 with monoclinic structure (PDF # 22-1099) was synthesized using the conventional solid-state reaction process. X-ray diffraction and Rietveld refinement were employed to investigate the phase compositions and crystal parameters. Combined with the refinement results, the structure-property relationship was analyzed using the chemical bonds theory of complex crystals. The surface microtopography was characterized using scanning electric microscope, and the dense and homogeneous microstructures could be observed at EuNbO4 ceramic sintered at 1125 °C. Infrared reflectivity spectra indicated the absorption of structural phonon oscillation might be the main contribution to polarization for EuNbO4 ceramic. The optimal dielectric properties with er = 19.1, Q × f = 15,014 GHz, and τf = −16.42 ppm/°C were achieved in EuNbO4 ceramic sintered at 1125 °C.

中文翻译：

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EuNbO4 陶瓷的晶体结构、红外光谱和微波介电特性

摘要 采用常规固态反应工艺合成了具有单斜晶结构的新型微波介电陶瓷 EuNbO4 (PDF # 22-1099)。X射线衍射和Rietveld精修被用来研究相组成和晶体参数。结合精修结果，利用复杂晶体的化学键理论分析了结构-性能关系。使用扫描电镜对表面微观形貌进行表征，在 1125 °C 烧结的 EuNbO4 陶瓷上可以观察到致密均匀的微观结构。红外反射光谱表明结构声子振荡的吸收可能是 EuNbO4 陶瓷极化的主要贡献。er = 19.1、Q × f = 15,014 GHz 和 τf = -16 时的最佳介电特性。