SOME ASPECTS ON THE GROWTH OF LEAD MOLYBDATE SINGLE-CRYSTALS AND THEIR CHARACTERIZATION

Lead molybdate single crystals were grown by the Czochralski technique . The growth conditions using resistive heating furnace are described in terms of internal radiant heat transfer through the crystal. Thorou gh investigations on the dependence of (i) the shape of the crystal-me lt interface on the internal heat transfer through the crystal and (ii ) incorporation of voids and inclusions and presence of strains on the seed rotation rate yielded high quality crystals. The tendency of lea d molybdate to have a convex crystal-melt interface shape despite a lo w axial thermal gradient and high seed rotation rate is studied in det ail. Annealing, optical transmission and chemical etching studies were also carried out in order to estimate the degree of perfection of the grown crystals.