Research of dielectric properties and electrical conductivity of LiNbO3:Zn crystals in the temperature range 310 – 900 К

Electrical conductivity and dielectric constant have been researched in a series of crystals LiNbO3:Zn(~ 4.0 – 9.0 mol. % ZnО in a melt) by application of constant voltage with a couple of electrodes (310 – 450К) and impedance spectroscopy (~ 600 – 900К). In order to compare results we have also researched electrical conductivity σdc of congruent LiNbO3congr and magnesium doped LiNbO3:Mg crystals. We have established that electron contribution to electrical conductivity of crystals LiNbO3:Zn and LiNbO3:Mg is greatly smaller than that of a congruent crystal LiNbO3congr. A decrease in conductivity is apparently connected with a restructure of LiNbO3 crystals at high concentrations of magnesium and zinc. Doping of crystals with Zn leads to drastic changes not only in the electron conductivity area (T < 450 K), but also in a lithium ion conductivity area (Т > 450 K). At this parameters of temperature dependence of lithium ion conductivity depend on both zinc concentration and crystallographic orientation of samples.