Low Frequency Dielectric Relaxation and Charge Transport in Bi₁₂TiO₂₀ Photorefractive Sillenite Crystals

Abstract:

Features of processes of a dielectric relaxation and charge transport in photorefractive sillenite crystals Bi₁₂TiO₂₀ at low frequency range are investigated. It was found that the dispersion of dielectric permittivity ε' in crystals Bi₁₂TiO₂₀ is characterized by its growth with lowering frequency and rising temperature. This behaviour may be related to existence of dipole-relaxation polarization mechanism. The frequency dependence of dielectric loss tgδ reveals the existence of low frequency relaxation peaks in the studied temperature range. From the conductivity dependence on the frequency and temperature it was found that conductivity σ increases as frequency increases in the low frequency range. The observed dependence σ(ω)≈Аω^s indicates that transport mechanism is due to hopping of carriers via localized electron states. The charge transport is thermally activated process in which activation energy E_a = (0.82±0.03) eV.

• Periodical: Key Engineering Materials (Volume 753)
• Pages: 163-167
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.753.163
• Online since: August 2017
• Authors: Rene Alejandro Castro*, Nadezhda Ivanovna Anisimova, Lilia Ansafovna Nabiullina, Evgeny Borisovich Shadrin
• Keywords: Charge Transport, Dielectric Relaxation, Photorefractive Sillenite Crystals

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