Characterization of lithium niobate by γ-ray diffraction

• Published in: Journal of crystal growth Vol. 79; no. 1; pp. 530 - 533
• Main Authors: Aubert, J.J., Couchaud, M., Calvat, C.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.1986
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/0022-0248(86)90489-6

The use of LiNbO 3 for acoustical and optical devices necessitates the growth of perfect single crystals. γ-ray diffraction provides a nondestructive tool to check mosaïc nature and its evolution along the crystals. The γ-ray diffraction experiments were performed on Czochralski grown crystals using reflection planes parallel and perpendicular to the growth direction. The results of these experiments were correlated with X-ray topographs of the same specimens. This characterization shows that lithium niobate crystals have a subgrain structure and that a large grain dis-orientation of up to 1° can exist perpendicular to the growth direction with the grains being rotated around the growth axis. X-ray topographs show that the grain boundaries are parallel to the growth direction for the Z and Y crystals and oblique in the other cases. The mosaic nature can be related to the internal stress and cracking of the crystals.