STRUCTURE DISORDER AND OPTICAL CHARACTERISTICS OF CONGRUENT LITHIUM NIOBATE CRYSTALS GROWN FROM BORON DOPED MELTS

Read more We have detected changes in the order of main cations and vacancies along the crystal polar axis and distortions of oxygen octahedra in lithium niobate crystals grown from congruent melt doped by non-metal boron. This was found due to concentration dependence of widths and intensities of Raman bands of the researched crystals. Boron was found to be absent from the crystal structure. The distortions of oxygen octahedra were demonstrated to be anisotropic. The distortion is connected with octahedra expansion along the polar axis. Nominally pure lithium niobate crystals grown from boron doped congruent melt are structurally uniform. The structure uniformity of such crystals is higher than the one of nominally pure congruent crystals. NbLi defects amount in such crystals is close to the amount in stoichiometric crystal. At the same time lithium niobate crystals grown from boron doped congruent melt possesses weaker photorefractive effect than the stoichiometric crystal.

Keywords:
lithium niobate, melt, doping, photorefractive effect, Raman scattering, photoinduced light scattering, laser conoscopy. 
УДК 535:361:456.34:882

STRUCTURE DISORDER AND OPTICAL CHARACTERISTICS OF CONGRUENT LITHIUM NIOBATE CRYSTALS GROWN FROM BORON DOPED MELTS