Defect configurations in as-grown mixed crystals of ammonium-potassium sulphate were revealed by chemical etch technique with greater details for the first time. Interesting features like symmetrical pyramidal pits, circular terraced pits, row of closely spaced pits forming low angle tilt boundary indicating branching of dislocations etc. were clearly observed using aqueous solutions of various inorganic salts (etchants) applied for different timings. It was found that addition of a salt generally promotes the formation of good pits. The results were briefly interpreted in the light of the Cabrera thermodynamic theory of dislocation etch pit formation. The optical and scanning micrographs showed a good correspondence between formation of etch pits and dislocations.

Revelation of Dislocation Etch Pits in Mixed Crystals of Ammonium-Potassium Sulphate, [K1-x(NH4)x]2SO4. S.Karan, S.S.Gupta, S.P.S.Gupta: Journal of Crystal Growth, 2001, 233[3], 555-60