ETCHING OF (0001) HABIT FACES AND MATCHED CLEAVAGES OF FLUX-GROWN STRONTIUM HEXAFERRITE CRYSTALS

Results of etching (0 0 0 1) planes of flux grown strontium hexaferrit e crystals in 85% H3PO4 at 120 degrees C and 37% HCl at 100 degrees C are presented. Fractography reveals one-to-one correspondence of cleav age patterns on the two matched (0 0 0 1) cleaved planes. Etch pattern s including hexagonal, point-bottomed pits with smooth sloping planes, hexagonal but flat-bottomed pits, geometrically centred hexagonal pit s with regularly spaced terracing, eccentric hexagonal pits with irreg ularly spaced terracing, a large flat-bottomed hexagonal pit with a sm aller point-bottomed hexagonal pit within it but having different geom etrical centres and flat-bottomed pits with a beak at their centres ar e illustrated. It is explained that they are indicative of normal, inc lined, stepped and bending dislocations in strontium hexaferrite cryst als. Pits due to impurity inclusions are also explained. The explanati ons are supported by the results of mismatchings of etch patterns on m atched cleavages.