Electron transfer in the structure of a photorefractive doped Bi$_{12}$TiO$_{20}$:Ru crystal

The ac conductivity of Bi$_{12}$TiO$_{20}$:Ru crystals has been studied in the frequency range 10$^{2}$–10$^{6}$ Hz and at temperatures 293–773 K. The experimental data have been analyzed in the framework of the model of correlated barrier hops. In this material, the potential barriers are due to the existence of a block structure, crystal lattice defects, and also the presence of a ruthenium impurity. The microparameters characterizing the charge transfer in doped bismuth titanate single crystals have been determined.