Dielectric parameters in Se 70Te 30 and Se 70Te 28Zn 2 chalcogenide glasses

Abstract

Temperature and frequency dependence of dielectric constant ( ε′) and dielectric loss ( ε″) are studied in glassy Se 70Te 30 and Se 70Te 28Zn 2. The measurements have been made in the frequency range (8–500 kHz) and in the temperature range 300 to 350 K. An analysis of the dielectric loss data shows that the Guintini's theory of dielectric dispersion based on two-electron hopping over a potential barrier is applicable in the present case. No dielectric loss peak is observed in glassy Se 70Te 30. However, such loss peaks exist in the glassy Se 70Te 28Zn 2 in the above frequency and temperature range. The Cole–Cole diagrams have been used to determine some parameters such as the distribution parameter ( α), the macroscopic relaxation time ( τ 0), the molecular relaxation time ( τ) and the Gibb's free energy for relaxation (Δ F).