Volnyanskii M.D.,Gonchar National Dnepropetrovsk University |
Plyaka S.N.,Gonchar National Dnepropetrovsk University |
Trubitsyn M.P.,Gonchar National Dnepropetrovsk University |
Obaidat Y.A.H.,Gonchar National Dnepropetrovsk University
Physics of the Solid State | Year: 2012
The electrical properties of a lithium heptagermanate (Li 2Ge 7O 15) crystal have been studied in DC and AC measuring fields at temperatures from 500 to 700 K. In a DC field, a substantial decrease of electrical conductivity σ with time has been detected. On the basis of kinetic dependences σ(t), estimates of the charge carrier diffusion coefficient D have been obtained. In the frequency range 10 1-10 5 Hz, the spectra of complex impedance ρ*(f) have been measured. The analysis of diagrams in the complex plane (ρ″-ρ′) has been performed within the equivalent circuit approach. It has been shown that, in the considered temperature and frequency intervals, the electrical properties of Li 2Ge 7O 15 crystals have been determined by the hopping conduction of interstitial lithium ions A Li and accumulation of charge carriers near the blocking Pt electrodes. © 2012 Pleiades Publishing, Ltd.