Electrical conductivity and conductivity relaxation in ZrF₄-BaF₂-YF₃-LiF glasses

Abstract

The electrical conductivity and the conductivity relaxation of the fluoride glasses in the system ZrF₄-BaF₂-YF₃-LiF with LiF content ranging from 10 to 60 mol% have been investigated in the frequency range 10 Hz-2 MHz and in the temperature range from 300 K to just below the glass transition temperatures. The conductivity shows a minimum and the activation energy a maximum for 20 mol% LiF content, which is interpreted as a crossover from F^-dominated conductivity to Li^-dominated conductivity at 20 mol% LiF. The glass decoupling index also shows a minimum for 20 mol% LiF, which is associated with the occurrence of the minimum for the conductivity. The conductivity relaxation parameter β, however, shows a minimum for 30 mol% LiF. A structural origin has been proposed to account for this.