Phonon behaviors and dielectric functions in Bi0.5Na0.5TiO3-based ceramics by Raman scattering and optical ellipsometry
Phonon behaviors and dielectric functions in Bi0.5Na0.5TiO3-based ceramics by Raman scattering and optical ellipsometry
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通过拉曼散射和光学椭圆光度法研究 Bi0.5Na0.5TiO3 基陶瓷中的声子行为和介电功能
DOI：
10.1111/jace.16175
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发表时间：
2019
影响因子：
3.9
通讯作者：
Sun Dazhi
中科院分区：
文献类型：
--
作者：
Jiao Shan;Chen Fangfang;Zhang Yi;Hu Zhigao;Duan Zhihua;Wang Feifei;Sun Dazhi
用变温椭圆偏振光谱和拉曼散射研究了(0.935‐x)Bi0.5Na0.5TiO3‐0.065BaTiO3‐xSrTiO3(BNBSTx)陶瓷的介电函数和晶格振动。利用Tauc-Lorentz色散模型对介电函数进行了分析，发现随着SrTiO_3的加入，禁带宽度和温度系数都有所增加。此外，与Bi和Ti局域声子模相关的声子模的频率、强度和/或半峰宽在退极化温度和介电常数-最大温度附近出现局部极大值/极小值，这表明结构正在发生转变。此外，锶的引入影响了TiO6的倾斜和Ti4+的偏心位移。这些结果对于在BNBSTx陶瓷中添加SrTiO_3增强响应功能具有重要意义。
The dielectric functions and lattice vibrations of (0.935‐x)Bi0.5Na0.5TiO3‐0.065BaTiO3‐xSrTiO3(BNBSTx) ceramics were investigated by temperature‐dependent spectroscopic ellipsometry and Raman scattering. Based on the analysis of dielectric functions with the Tauc‐Lorentz dispersion model, it was found that the band gap and the temperature coefficient increased with the addition of SrTiO3. Moreover, the frequency, intensity and/or full width at half maximum of phonon modes related to Bi and Ti‐localized phonon modes exhibited local maximum/minimum around the depolarization temperature and permittivity‐maximum temperature, which indicated the ongoing structural transformation. In addition, the Sr introduction affected the TiO6tilting and the off‐center displacement of Ti4+. These results seem to be significant for the enhanced response functions with the addition of SrTiO3in BNBSTxceramics.