Growth Spirals on Crystals of WO₃

Abstract

Growth spirals were observed on the (001) and {111} surfaces of WO₃ crystals which were prepared by sublimation. Spirals on (001) are of ‘circular symmetry’, but spirals on {111} are of a characteristic shape which is explained by crystal structure. It was found that in any one region of the crystal the dislocations were not only predominantly of the same sign but also had the same strength. The movement of dislocation has been illustrated. Besides these spirals the layer formation from edges or corners of crystals was observed.