用化学腐蚀、光学显微镜、X射线形貌术以及电子显微分析等方法研究了引上法生长的BeAl_2O_4:Cr晶体中的缺陷.其结果如下:1)获得了对低指数面(100)、(010)及(001)面位错的理想腐蚀剂,2)晶体中的位错分布不均匀,位错产生的来源有二:一是从晶种中,另一是由包裹物引起.大多数位错是刃型位错,其柏格氏矢量为〈100〉方向、滑移面为(010)面.3)在晶体中常出现的包裹物如气泡,管状物及第二相沉积物,它们是由于原料中的杂质及生长过程中的组分过冷引起的.

The defects of alexandrite crystal (BeAl2O4: Cr) grown by Chochralski technique were investigated by chemical etching, optical microscopy, X-ray diffraction topography and electron microprobe analysis. The results obtained are summarized as follows: (1) Eolicdle dislocation etchants were restablished on the (1 0 0), (0 1 0) and (0 0 1) surfaces. (2) The distributions of dislocations in crystals are nonuniform. There are two sources for the dislocation production. One is seed and other is inclusions. Most of the dislocations are edge ones, their Burger's vectors are in <1 0 0> direction and glide planes are (0 1 0). (3) The main inclusions such as bubbles, tunnels and secondary phase pricipitate particles often appear in grown crystals, which are caused by impurities in raw material and constitutional supercooling during growth.