THE EFFECT ON THERMAL AND ELECTRICAL-PROPERTIES OF THE ADDITION OF GA2O3 TO GLASSES OF THE AG2O-P2O5-AGI SYSTEM

Glasses of the following general formula were prepared in order to inv estigate their electrical and thermal properties: 0.65((1 + x)Ag2O.yGa 2O3.(1-Y)P2O5). 0.35 AgI (0 less-than-or-equal-to x less-than-or-equal -to 0-6) (0 less-than-or-equal-to y less-than-or-equal-to 0.2). Experi mental data indicate that the substitution of Ga2O3 by P2O5 increases both the glass transformation temperature T(g) and the electrical cond uctivity sigma. It has been hypothesised that tetrahedral GaO4 groups are in equilibrium with units in which Ga+3 ions have higher coordinat ion (possibly six as in the pure Ga2O3 structure). The dependence on c omposition of the parameters of the Arrhenius type equation of sigma a re explained on the basis of the reported structural model of AgI micr odomains in a silver phosphate matrix and on the basis of the diffusio n path model for ionic conduction. Experimental results suggest that A g+ migration paths involve sites other than the ones near I- ions.