Crystal growth and characterization of Li_xLa_(1−x)/3NbO₃ using Czochralski method

Abstract

Single crystals of Li_xLa_(1−x)/3NbO₃ were grown in air using Czochralski method from La-poor melt. The lithium-ion conductivity of the crystals was measured. The length and maximum diameter of the boule grown were 23 and 20 mm, respectively. The boule contained no inclusions but was covered with a very thin polycrystalline film of LaNbO₄ and LiNbO₃ in its upper region. The composition of the crystals grown was estimated to be x = 0.15 and the starting melt composition was x = 0.20. The ionic conductivity of the crystal was anisotropic with σ_[100] = 2.8 × 10⁻⁴ S cm⁻¹ and σ_[001] = 9.7 × 10⁻⁵ S cm⁻¹ at 306 K. The activation energy, E_a of these conductivities was almost the same in the range of 0.28–0.29 eV. Further, we discussed the anisotropic lithium-ion conductivity of the crystal.