Role of Cu additive on the dielectric relaxation of Se₇₅Te₂₅ and Se₈₅Te₁₅ glassy alloys

Department of Physics, Christ Church College, Kanpur, 208001, India

Corresponding author: dr_santosh_kr@yahoo.com

Received: 19 February 2010
Revised: 8 April 2010
Accepted: 13 April 2010
Published online: 17 June 2010

Abstract

The effect of Cu additive on the dielectric relaxation of two binary Se-Te glassy systems, comparing the properties of a-Se₇₅Te₂₅, a-Se₈₅Te₁₅ and a-Se₇₅Te₁₅Cu₁₀ alloys has been reported. The temperature and frequency dependence of dielectric parameters in Glassy Se₇₅Te₂₅, Se₈₅Te₁₅ and Se₇₅Te₁₅Cu₁₀ alloys are studied by measuring capacitance and dissipation factor in the frequency range (1 kHz-5 MHz) and temperature range (300-350 K). A Debye like relaxation of dielectric behavior has been observed. A comprehensive study on the relaxation mechanism revealed that the presence of grains and grain boundaries across the pallet thickness is the basic relaxation process. A detailed analysis shows that the observed dielectric loss is in agreement with the Guintini's theory of dielectric dispersion based on two electron hopping over a potential barrier and is applicable in the present case. Dielectric constant (ε’), dielectric loss (ε”), loss tangent (δ) and capacitive reactance (X_c) are found highly frequency and temperature dependent. Dependence of these dielectric parameters over the metallic impurity Cu, has also been found in the present glassy system and has been discussed in terms of electronegativity difference between the elements used in making the aforesaid glassy system.