Journal of Crystal Growth, Vol.307, No.2, 421-426, 2007
Defect structure and photorefractive properties of In : Eu : Fe : LiNbO3 Crystals with various Li/Nb ratios
In: Eu: Fe: LiNbO3 crystals were grown by the Czochralski technique with various ratios of Li/Nb = 0.946, 1.051, 1.200, 1.382 in the melt. The crystal composition and defect structure were analyzed by the UV-visible and IR spectroscopy and X-ray diffration. The results showed that increasing the Li/Nb ratio can decrease the In3+ doping threshold concentration of In: Eu: Fe: LiNbO3 crystals. In two-wave coupling experiments, the writing and erasure time constants, maximum diffraction efficiency, photorefractive sensitivity, photoconduction, photovoltaic field and space-charge field of the crystals were measured and calculated. The dependence of the photorefractive properties on the defect structure of In: Eu: Fe: LiNbO3 crystals were discussed. (c) 2007 Elsevier B.V. All rights reserved.