Composition dependent electrical conductivity of (1-y)[(1+x)Ag2O.P2O5]yAgI glasses in the range 0.55<=y<=0.70, 0<=x<=0.4

Glasses of the following general formula were prepared in order to investigate their electrical and thermal properties: (1-y) [(1+x) Ag2O.P-2 O-5]yAgI, 0.55 less than or equal to y less than or equal to 0.70, 0 less than or equal to x less than or equal to 0.4. Experimental data confirm that, as reported in the literature, the increase of the AgI content makes the electrical conductivity, sigma, increase and the glass transformation temperature T-g decrease. The increase of sigma is primarily due to the decrease of the activation energy for conduction, E(sigma). The results can be interpreted on the basis of the model reported in the literature of a glass demixed in AgI microdomains and a phosphate matrix. They suggest that the Ag+ migration paths also involve sites other than the ones near I- ions and that E(sigma) for the AgI doped glasses can be considered an average of the values relative to the various phases present. As it happens in glasses poorer in AgI content, a linear relation is observed when the ratio E(sigma)/E(sigma ma) of the activation energies of AgI doped, E(sigma) and undoped, E(sigma ma) glasses is plotted against the fraction of Ag+ ions introduced as Ag2O.