Raman spectroscopy investigation on (Pb1−xLax)(Zr0.90Ti0.10)1−x/4O3 ceramic system

A Raman spectroscopy study at room temperature was carried out on (Pb_1−xLa_x)(Zr_0.90Ti_0.10)_1−x/4O₃ ceramics (x = 2, 3, 4 at%). The results were analyzed considering the x-ray patterns at room temperature showing a mixture of two phases: a rombohedral-ferroelectric phase and an orthorhombic-antiferroelectric, increasing the% of the second one with the lanthanum concentration. For x = 3 at%, the analysis was also carried out in a wide temperature range. Two anomalies were evaluated, one around 363 K, which has been associated to a ferroelectric-antiferroelectric phase transition; the second one around 430 K, which has been associated to a transition from an incommensurable state to a ferroelectric phase.     

Phase transitions in PbZr0.72Sn0.28O3 single crystals studied by Raman spectroscopy

ABSTRACT

Raman light scattering measurements in the temperature range from 80 to 830 K were performed on a PbZr_0.72Sn_0.28O₃ single crystal. The frequencies of the Raman lines were analyzed and discussed in terms of the sequence of structural phase transitions. It was found that Raman spectrum displays important changes near 440, 480 and 493 K. The incorporation of more than 25 mol% of Sn⁴⁺ ions into the structure of PbZrO₃ enhances polar fluctuations above T_C as compared to the less Sn-doped crystals. These fluctuations lead to appearance of a ferroelastic intermediate phase below T_C. It is demonstrated that the structural phase transformation in PbZr_0.72Sn_0.28O₃ can be considered as the result of softening of a number of modes.     

基于相变换能机理的反铁电陶瓷水声换能器初探

阐述了改性锆锡钛酸铅Pb(Zr,Sn,Ti)O3(PZST)反铁电陶瓷作为一种基于相变换能机理的大应变电致伸缩材料的性能特征以及作为水声换能器新型有源材料的优势。采用掺镧改性锆锡钛酸铅PbLa(Zr,Sn,Ti)O3(PLZST)反铁电陶瓷材料首次设计制作了纵振式反铁电陶瓷水声换能器。试验结果表明,PLZST反铁电陶瓷用于水声换能器研制在技术上是可行的,与压电陶瓷换能器比较,目前反铁电换能器样品的等效发射电压灵敏度提高3~5dB以上。根据实验情况,认为在发射电压灵敏度和声源级方面具有进一步提升的潜力。