Etch Pits Corresponding to Dislocations in Ferroelectric Guanidinium Aluminum Sulfate Hexahydrate

Abstract

Cleavage surface of ferroelectric G.A.S.H. crystal was etched with a mixture of water and ethyl alcohol, followed by rinsing in benzene. Identical etch pits were observed on matching cleavage faces. Density of the pits is 10⁴/cm² in the order of magnitude. Mechanical shock produces etch pits. Successive etching causes growth of pits at the unchanged locations. These facts lead us to conclude that the pits must correspond to dislocations. Patterns of etch pits on the upper and the lower cleaved faces of the crystal indicated that dislocation penetrates the crystal several hundred micron thick. Pair arrangements and linear arrays of etch pits were observed. Etch pits, of which the deepest points differ from the centers of triangles, correspond to dislocations not perpendicular to cleavage surface.