Effect of doping on the Raman modes in MgO‐doped lithium niobate crystals

Abstract Raman spectra of a series of MgO‐doped congruent LiNbO 3 crystals were obtained with MgO concentrations up to 30 mol.%. Single crystals were successfully grown and no precipitates were discovered. The intensity, frequency and line width of the Raman phonons were studied as a function of doping percentage. An abrupt change was observed near the composition of 7.5 mol.% of MgO‐doped LiNbO 3 crystal. From the spectral changes it is proposed that Mg 2+ replaces the mis‐sited Nb 5+ cation at Li sites first. When these mis‐sited Nb 5+ cations have been completely replaced, the Mg 2+ cation then replaces the Li + cation and creates vacancies at Li + sites.