CALCULATION OF THE POINT DEFECT CONCENTRATION OF THE CATION SUBLATTICE AND HYDROXYL GROUPS IN LITHIUM NIOBATE CRYSTALS OF DIFFERENT COMPOSITION

Abstract

The IR absorption spectra in the region of stretching vibrations of OH - groups of lithium niobate crystals of stoichiometric and congruent compositions are studied. The results of calculations of the OH - groups concentration, the Li / Nb ratio and the concentration of point defects NbLi and VLi coincide with the literature data. The phase diagram of lithium niobate confirms these results. It is shown that an increase in the number of free protons that contribute to conductivity can lead to reducing the optical damage and higher electrical conductivity and the rate of thermal fixation of holograms.

Keywords

• single crystal
• lithium niobate
• defects
• ir absorption spectra
• stretching vibrations of oh - group