The surfaces of the melt grown doped KMgF3 crystals, grown by czochralski p
ulling technique with 5% doping of NiF2, were investigated using an optical
microscope The crystals exhibit striations of type-I and type-II. From the
topography of matched cleavages, it is demonstrated that these crystals ex
hibit perfect cleavages along (1 0 0) planes. The results of etching of (1
0 0) cleavages at different concentrations of the etchant are reported. Ten
percent H2SO4 is shown to be the most suitable concentration for delineati
ng dislocations intersecting (1 0 0) planes of these crystals. The shape of
the etch pits is dependent on concentration of the etchant. Hundred percen
t H2SO4 produces circular, whereas lower concentrations produce square etch
pits. Besides isolated dislocations, low angle grain boundaries and helica
l dislocations are shown to exist. Variations of lateral, vertical and area
l etch rates with etchant. concentrations of the etchant are graphically an
alysed. (C) 2001 Elsevier Science B.V. All rights reserved.