Abstract The structure origin of microwave dielectric properties in A/B-site substituted LaTiNbO 6 ceramics with different crystal structures was explored by means of Raman scattering and infrared reflection spectra. Compared with the monoclinic (M) phase, the broadening of the Raman modes associated with B-O stretching and bending vibrations in the orthorhombic (O) phase was believed to be a result of the increased octahedral distortion. The Raman mode at 659 cm −1 was assigned to the stretching vibration of B–O–B and O–B–O bonds in the unique interlayer chain structure of O phase. The Raman modes of the BO 6 tilting within 340–520 cm −1 suggest that different octahedral connection ways should be one of the vital reasons why M and O phases own opposite-sign temperature coefficient of resonance frequency τ f . Moreover, the result of infrared reflection spectrum fitted with a four-parameter semiquantum model indicates that the dielectric response of both M and O phases would mainly originate from the A-BO 6 external vibrations in the far-infrared frequency, particularly their AO 8 structure units. These results would provide useful insights into the structure-property relation in the RETi(Nb,Ta)O 6 (RE: rare earth) material system.

中文翻译：

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A/B位取代正交/单斜LaTiNbO 6 微波介质陶瓷的拉曼散射和红外反射率研究

摘要 通过拉曼散射和红外反射光谱研究了不同晶体结构的A/B位取代LaTiNbO 6 陶瓷微波介电性能的结构起源。与单斜 (M) 相相比，正交 (O) 相中与 BO 拉伸和弯曲振动相关的拉曼模式的展宽被认为是八面体畸变增加的结果。659 cm -1 处的拉曼模式归因于 O 相独特的层间链结构中 B-O-B 和 O-B-O 键的伸缩振动。BO 6 的拉曼模式在340-520 cm -1 范围内倾斜，表明不同的八面体连接方式应该是M 和O 相具有相反符号的共振频率温度系数τ f 的重要原因之一。而且，红外反射光谱拟合四参数半量子模型的结果表明，M和O相的介电响应主要来源于远红外频率的A-BO 6 外部振动，特别是它们的AO 8 结构单元。这些结果将为 RETi(Nb,Ta)O 6 （RE：稀土）材料体系中的结构-性能关系提供有用的见解。