Grown-In Dislocations in Calcium Tungstate Crystals Pulled from the Melt

Abstract

Etch pits on (001) surfaces of calcium tungstate crystals, formed on treatment with hot dilute solutions of hydrochloric acid, were identified to be dislocation etch pits. The technique is able to follow the motion of dislocations during annealing by the formation of new sharp-bottomed pits adjacent to flat-bottomed pits at the initial dislocation positions. Inclusions, both solid and gaseous, are an important source of dislocations in crystals of calcium tungstate grown from the melt.