OBSERVATION OF DISLOCATIONS AND SUBBOUNDARIES IN OPTICALLY ACTIVE CRYSTAL Bi12GeO20 BY MEANS OF REFLECTION BIREFRINGENCE TOPOGRAPHY
应用反射光双折射貌相法观察旋光性晶体锗酸铋中的位错及亚晶界

In this paper, we studied the birefringence topography of bismuth germaniun oxide which hare a strong natural optical activity. It is discovered that the natural optical activity of the crystal may be compensated completely with a reflection polarised light microscopy so that the birefringence images of dislocations and subboundries were observed. The Burgers vectors of dislocations were found to be of the type of 1/2 ( 111), (100) and (110).