Anisotropy of anionic conductivity in single crystals of CeF$_{3}$ superionic conductor

The anisotropy of anionic conductivity in crystals of a superionic conductor CeF$_{3}$ with the tysonite structure (sp. gr. $P\bar3с1$) has been studied for the first time. The conductivity measurements at temperatures from 300 K to 600 K were carried out along the principal a- and c-axes of trigonal unit cell of the crystal. The maximum value of electrical conductivity is observed along the c-axis. The superionic CeF$_{3}$ crystals have the weak anisotropy of electrical conductivity equal to $\sigma_{\|c}/\sigma_{\|a}$ = 2.4, $\sigma_{\|c}$ = 5.6$\times$10$^{-4}$ S/cm at 500 K. The anisotropy effect of anionic conductivity in individual fluorides with the tysonite structure is discussed in connection with the peculiarities of their atomic structure.