引上げ法による氷単結晶の製作(第2報)
X線トポグラフによる転位の観察
1969 年 38 巻 6 号 p. 567-573
詳細
1969 年 38 巻 6 号 p. 567-573
The method of X-ray diffraction topography was used to examine dislocation structures in large single crystals of ice grown from water by a modified Czochralski's method. Character-istic features of dislocations in the crystals are as follows. Screw dislocations of which Burgers vector is c [0001] hardly appear in the crystals grown to the direction of c-axis, whereas small angle boundaries consisting of edge dislocations of Burgers vector a/3 (1120) on the basal plane extend to the direction of the c-axis. In the crystals grown to the direction perpendi-cular to the c-axis, the dislocations run parallel to the direction of growth.
These results suggest different mechanisms of crystal growth with respects to the growth direction; two dimensional nuclei mechanism is prevailing in the case of c-axis parallel growth and spiral growth around screw dislocations is occuring in the case of c-axis perpendicular growth.
