Properties and structure of Agx(As0.33S0.67)100-x bulk glasses

In this paper, bulk glasses with composition Ag-x(AS(33)S(67))(100-x) (x = 0-25 at.%) were investigated. Amorphous structure of samples was confirmed by X-ray diffraction analysis. The structure was deduced from Raman spectra measured for all silver contents in the As-S matrix. The thermal properties (T-g - glass-transition temperature, T-s - softening temperature, T-c - temperature of crystallization, T-m - melting temperature and C-p - specific heat capacity), were obtained from modulated differential scanning calorimetry (MDSC) and/ or thermomechanical analysis (TMA). Optical properties were measured by spectral ellipsometric spectroscopy. Refractive indices were calculated using the Cauchy model from the ellipsometric parameters Psi, Delta. Refractive index increasing toward higher silver concentration has been shown. The value of the refractive index difference (An) between AS(33)S(67) and Ag-25(AS(33)S(67))(75) is about 0.4. All studied glasses behave as ionic conductors from the point of their electrical properties. Their ac conductivity increases with increasing content of silver. As determined from the comparison of ac and dc conductivities, the contribution of electronic conductivity to the overall conductivity is very low and decreases from about 1% for the glass with 10 at.% of Ag to about 0.01% for the glass with 24 at.% of Ag. (c) 2007 Elsevier B.V. All rights reserved.