Ionic and electronic conductivity of glasses in the P2O5-V2O5-Na2O system

The conductivity of glasses in the gamma P2O5 - (1-y) [l-x) V2O5 - x Na2O] system is studied as a function of temperature and composition. For all com positions, the conductivity variations as a function of temperature follow an Arrhenius type relationship. The activation energy and pre-exponential f actor values determined for the V2O5 richest compositions are lower than th ose obtained for the rich ionic domain. Isothermal variations of the conduc tivity as a function of composition show deep minima for molar ratios x nea r 0.65. On either side of these minima, the conductivity is mainly electron ic (x < 0.6) or ionic (x > 0.8). The variations are interpreted assuming a prevailing diluting effect of the non predominantly present oxide with no i nteractions between the electronic and ionic charge carriers.