钽酸锂铁电相变的喇曼光谱研究

本文测定了钽酸锂晶体从室温到居里温度以上(20—800℃)的喇曼光谱。没有观察到软模现象。我们发现在居里点附近,铁电相和顺电相的喇曼光谱十分一致,经过居里点喇曼光谱不发生变化。根据这个新的实验结果和文献上关于用中子衍射测定的晶体结构资料,我们做出了钽酸锂的铁电相变为有序无序型的推论。 关键词：

RAMAN SPECTRA STUDY OF FERROELECTRIC PHASE TRANSITION IN LiTaO3

The Raman spectra of LiTaO₃ have been studied from 20℃ to 800℃. No softening of ferroelectric mode has been detected. The striking feature of our results is that the Raman spectra of the ferroelectric phase merge into the paraelectric phase without any appreciable discontinuity at the phase transition. On the basis of these new experimental results and the crystal structure data in literature, we suggest that the ferroelectric phase transition in LiTaO₃ may have an order-disorder character.