92%Pb(Zn1/3Nb2/3)O3-8%PbTiO3晶体的生长缺陷和形貌

应用环境扫描电子显微术（ESEM）和同步辐射X射线白光形貌术研究了92％Pb(Zn1/3Nb2/3)O3-8%PbTiO3晶体的表面形貌和缺陷，为生长高质量的该单晶材料提供重要的参考。从晶体自然显露面（111）面的ESEM缺陷形貌像中，观察并研究了诸如生长丘，位错蚀坑，小角晶界，包裹物，空洞或裂缝等生长缺陷，并分析了导致这些缺陷出现的原因是生长过程中的温度波动，过快的降温速度等因素。从该晶体的同步辐射X射线白光形貌像中也观察到了包裹物或空洞等缺陷。由该晶体表面出现的直形台阶，多层板块状台阶结构及其精细结构的ESEM形貌像可知，在PZN－8％PT晶体的高温溶液法生长中，起主导作用的生长机制为二维成核层状生长机制。

GROWTH DEFECTS AND TOPOGRAPHY IN 92%Pb(Zn1/3Nb2/3)O3-8%PbTiO3 Crystal

To grow large and good quality 92%Pb(Zn 1/3 Nb 2/3 )O 3-8%PbTiO 3 (PZN-8%PT) crystals, the surface topography and defects, and the images of the natural surface growth defects of the (111) faces were investigated by means of the techniques of Environmental SEM(ESEM)and synchrotron radiation topography. From this group of appearing faces, some defects such as growth hillocks and etch pits, low_angle grain boundaries, inclusions, hollows or fissures were observed. The images of inclusions or hollows were also obtained by the method of synchrotron radiation topography. These defects are induced by the fluctuation of growth conditions such as temperature fluctuation. In addition, the appearance of stripe_like steps, multilayer lamellar steps and finer step structure indicates that the dominant growth mechanism of growing PZN-8%PT crystals by the PbO flux method is layer_by_layer growth mechanism controlled by two_dimension nucleation.