Influence of the lithium niobate crystals composition on mobility of Н+ and Li+ ions in the temperature range 300–450 K

IR absorption spectroscopy and electrical conductivity have been studied in a series of lithium niobate crystals. We have established that mobility of Li+ ion sharply increases when a crystal approaches stoichiometric composition. This is especially true along the polar direction of a crystal. We have also established that doping of lithium niobate crystals with under-threshold concentrations of non-photorefractive Mg and Zn substantially decreases mobility of Н+ ions. •Li+ ions mobility increases even at 400 K when LN composition approaches stoichiometry.•Н+ ions mobility decreases at LN doping with Zn and Mg in threshold concentration.•LiNbO3:Zn,Fe crystals can be optimal for stocking of volume phase holograms.