| LBO single crystal is a new type of piezoelectric materials and belongs to the tetragonal crystallographic system. Due to the high surface acoustic wave (SAW) coupling coefficient, wide source of raw material and no pollution to the environment, LBO crystals have been developed into production by the Bridgman technique, which was invented by Chinese scientists. However, appearance of macroscopic defects is still the main problems faced in the mass-production of large size LBO crystals. Studying the mechanism of defects formation can help reducing the generation of defects by improving the growth process.I played a role in part of the LBO crystals growth by the Bridgman method, and collected many LBO crystal samples with defects such as cracks?clouds a striations and twins on the base of the long-time accumulation of production in the laboratory. Then the samples were polished and etched.LBO crystals have been grown by the Bridgman method suing the home-made furnace, and the orientations of the crystals are<110> or <001> directions. Finally I preliminary mastered the growth process of LBO crystals.T observed different morphology of twins in LBO crystals. All twins in LBO crystals take place according to Dauphine rule with twinning axes<100> and <010>, which means that crystallographic axes<100> and <010> are the rotation by 180°. In this paper, we discussed the origin and formation mechanism of LBO crystals, which may be helpful in putting forward some suggestions for the LBO crystal growth. |
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