【摘要】 从室温至180℃测量了BaTiO₃和Ce:BaTiO₃单晶的偏振喇曼谱,在X（ZZ）Y几何配置下发现了三条频率分别为986,1204和1480cm^-1的新谱线.根据喇曼散射截面的温度依赖关系,确认这些新谱线对应二阶喇曼散射,而A₁（TO）谱中位于275和514cm^-1处的非对称宽峰则属于一阶喇曼散射.在此基础上,对立方相BaTiO₃的喇曼谱和结构相变机制进行了讨论.通过比较BaTiO₃与Ce:BaTiO₃喇曼谱随温度的变化,发现掺Ce降低了BaTiO₃晶体的Curie温度,与介电系数的测量结果相符.更多还原

【Abstract】 Raman spectra of BaTiO3 and Ce: BaTiO3 single crystals have been recorded between room temperature and 180℃. Three new bands at 986,1204 and 1480 cm-1 in the X(ZZ) Y geometry are discovered. Based upon the temperature dependence of Raman scattering cross sections, the new bands are attributed to the second-order Raman spectra of BaTiO3, while the strong asymmetry bands at 275 and 514 cm-1 in Al(TO) spectrum are confirmed to be of first order. On the basis of above results, the Raman spectra of cubic BaTiO3 and the model of phase transitions are discussed. It is found that doping with Ce in BaTiO3 lowers its Curie temperature, which agrees with the experimental results of dielectric constants.更多还原