Microstructure of striae in 〈04¯41〉-oriented lithium niobate single crystal grown by Czochralski method

In 〈04¯41〉-oriented lithium niobate single crystals, striae of planar defect lying on nearly (2¯110) were formed during the Czochralski growth. A stria was a small angle tilt boundary including a set of undissociated edge dislocations with the Burgers vector of a/3[2¯110], arranged at similar intervals of about 1μm. The dislocations extended perpendicular to the growth interface, leaving from the basal plane, presumably for the reduction of their strain energy during the growth. The formation process was discussed in terms of thermal stress at the growth interface during crystallization.