锆钛酸镧铅结构象和缺陷

LEAD LANTHANUM ZIRCONATE TITANATE STRUCTURE IMAGES AND DEFECTS

锆钛酸镧铅(简称PLZT)是一种十分重要的铁电材料.利用PLZT透明陶瓷的场致相变,还有可能在图象存贮和显示中得到应用.目前,在利用La/Zr/Ti比为7.9/70/30或8/65/35的PLZT透明陶瓷制作平面显示器、散射光开关和电光图象存贮器等方面开展了不少工作.PLZT透明陶瓷的基本组成是锆钛酸铅掺La改性,形成(Pb,La)(Zr,Tj)O四元系固溶体.化学式倾向于:Pb,La(Zr,Ti)O.其中,La的浓度x可在2~30%之间改变,而Zr与Ti的相互比例可连续变化.为了提高PLZT性能,人们往往通过改变这一比例加以实现.然而,我们的计算结果指出,这一比例的改变将使晶格能发生变化.我们用高分辨电子显微镜在晶格水平上对配比为8/65/35和7.9/70/30的PLZT进行了观察,发现配方7.9/70/30有更多的缺陷.计算表明,这可能是由于7.9/70/30的晶格能比8/65/35相对较低造成的.

The microstructures of lead lanthanum zirconate titanate(PLZT)ceramics which have mole ratios of 8/65/35 and 7.9/70/30 were observed by high resolution electron microscope at lattice level.For the first time,the structure images of the PLZT ceramics were obtained.The results indicate that the samples with mole ratio 7.9/70/30 have more defects than that with mole ratio 8/65/35 so the samples with ratio 8/65/35 are much more stable.