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This paper reports a comparative study of the homogeneity of LiNbO 3 〈Mg〉 (≥5 mol % Mg) crys tals grown from a charge synthesized using Nb 2 O 5 〈Mg〉 prepared through homogeneous magnesium doping of a reextract in the Nb 2 O 5 extraction step, and LiNbO 3 〈Mg〉 crystals prepared through direct doping of a growth charge. The LiNbO 3 〈Mg〉 crystals were characterized by optical microscopy and Raman spectros copy. The results demonstrate that the LiNbO 3 〈Mg〉 crystals prepared using homogeneous doping are more structurally uniform.

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Electrophysical characteristics have been studied in ceramic and single crystal LiNbO3 of congruent and near-congruent composition. The comparative study has been carried out in a wide temperature range (290-800 K). Dispersion of the real part of the dielectric constant ε′ has been considered. Temperature dependences ε′(T) and σ(T) have been obtained and value of static conductivity has been determined in ceramic and single crystal LiNbO3 in the given temperature range. Temperature dependences of specific static conductivity σ dc have been obtained due to impedance spectroscopy data analysis. Ceramic LN conductivity has been shown to be much higher in the whole studied temperature range. Charge carriers activation enthalpy in high-temperature area (above 420 K) is H a = 0.88 eV for ceramic LN and H a = 1.24 eV for single crystal LN.