对Zr与Ti的原子比约为52/48, 掺杂了少量La、Mn和 Nb的PLZT铁电陶瓷进行了不同 温度下的原位Raman谱观测, 对所获得的谱图进行温度分布修正, 再利用阻尼-谐振-振荡器模型的光谱响应函数及Gauss 分布函数对所得结果进行分峰拟合, 得到了各Raman峰的波数和峰强随温 度的变化规律. 结果表明, 准同型相界附近的PLZT铁电陶瓷在 47—600 ℃升温过程中, 于240和360 ℃分别发生两次相变, 表明 样品中可能存在混合相；通过比较未极化和极化样品的Raman 谱峰的变化结果, 分析了预极化处理对相变的影响.
In-situ Raman spectroscopy was employed to investigate PLZT ceramics (atomic ratio Zr/Ti=52/48, doped with small amount of La, Mn and Nb) at different temperatures. The observed Raman spectra were modified by the Bose population factor, and curve-fitted by the damped-harmonic-oscillator model and Gauss distribution function. Accordingly, the variations of Raman shifts and intensities of soft modes with temperatures were obtained. It confirmed that two types of phase transitions near morphotropic phase boundary (MPB) occurred at 240℃ and 360℃, respectively, when the temperatures increased from 47 to 600℃, indicating possible presence of mixed phases in PLZT ceramics. The effects of pre-polarization on phase transition are briefly discussed based on a comparison between the changes in Raman shift and intensity of soft mode observed with the unpoled powders and poled bulk specimens.
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