升温对[100]_(cub)弛豫铁电PMN-32PT单晶电畴组态演变的影响

Effects of Temperature Field on Domain Configuration Evolution in the [100]_(cub)-oriented Single Crystal of PMN-32PT by Heating

采用热台偏光显微镜观察以ACRT+Bridgman法获得、经过金相抛光处理的弛豫铁电PMN-32PT单晶[100]cub切型电畴组态,考察了未退火状态下[100]cub切型单晶的消光行为及连续升温对本征电畴与由抛光机械应力诱导非本征电畴组态的影响。结果表明,在升温过程中,PMN-32PT单晶非本征电畴在三方-四方铁电相变后消失;本征电畴组态的变化表现为两个阶段,第一阶段畴先细化后宽化,第二阶段进行铁电-顺电相变,相变过程缓慢,持续范围为168～177℃,且与三方-四方相变出现次序相反。

The ferroelectrics domain of the [001] direction in the PMN-32PT single crystal were observed by polarizing microscope with hot stage. The extinction behavior and the effects of phase transforms and domain configuration of [001]cub oriented PMN-32PT single crystals without annealing were studied. The result indicated that the phase of the PMN 32PT single crystals prepared by ACRTq-Bridgman method was rhombohedral phase that extinction angle was 45°. In heating run, the domain of [001]cub-oriented PMN-32PT single crystals exhibited a two-step variation. Firstly, domain refined and then grew up. Secondly, the ferroeleetric phase transformed to paraelectric phase. The phase transition was slow and the range of the temperature varied from 168℃ to 177℃. When this occured, it was different that the crystal structure transit from ferroelectric phase to paraelectrie phase and the crystal structure transit from rhombohedral phase to tetragonal phase.