Frequency Dispersion of Conductivity and Complex Impedance in Li₂Ge₇O₁₅ Single Crystal

Abstract

Electric properties of lithium heptagermanate Li₂Ge₇O₁₅ single crystal have been studied in AC external field (10¹–10⁵ Hz) in the temperature range 300–700 K. It has been shown that below 500 K conductivity σ is determined by polarization processes whereas above this temperature charge transfer phenomena become dominant. It is assumed that at high temperatures conduction is determined by mobile interstitial lithium ions А_Li. The spectra of complex impedance ρ* testify for hopping А_Li conduction and accumulation of charge carriers near to blocking Pt electrodes.

Keywords:

• Ionic conduction
• impedance spectra
• Li₂Ge₇O₁₅ crystal