Ac conductivity and dielectric properties of TlIn0.975Y0.025S2single crystal

✍ Scribed by El-Nahass, M. M. ;El-Barry, A. M. A. ;Abd el Rahman, S.

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 302 KB
• Volume: 203
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200521304

✦ Synopsis

Abstract

The frequency dependence of the electrical conductivity, dielectric properties, and dielectric loss of TlIn~0.975~Y~0.025~S~2~ single crystal was studied in the temperature range 303–473 K over the frequency range 10^2^–10^5^ Hz. A characteristic frequency, ω~p~, was found involved in the conduction mechanism, above which the electrical conductivity increased sharply. This observed variation was explained according to Summerfield theory for hopping conductivity which predicted a scaling law for the low‐frequency ac conductivity: σ(ω) = σ(0) [1 + (ω/ω~p~)^β^]. At higher frequency (≥4 kHz) the ac conductivity increased sharply with frequency according to the power law σ~ac~ ≈ Aω^s^. The analysis of the ac conductivity at higher frequency showed that the correlated barrier hopping model is the most appropriate mechanism. Also, the loss tangent, tan__δ__, was predicted to decrease with increasing frequency. Capacitance was found to decrease with increasing frequency and decreasing temperature. The capacitance reached a minimum value, C~min~, at higher frequencies. Finally the maximum barrier height, W~M~, the hopping energy, ω~H~, the relaxation time, τ, and the density of states, N(E~f~), for TlIn~0.975~Y~0.025~S~2~ single crystals were determined. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)