The direct-current conductivity, and the conductivity relaxation, of glasses with various BaF2 and LiF contents were studied at temperatures ranging from 300K to the glass transition temperature, for frequencies ranging from 10Hz to 2MHz. It was observed that the conductivity went through a minimum, and the activation energy a maximum, at 20mol%LiF. The glass decoupling index also went through a minimum at the same composition and was associated with the minimum in the conductivity. A small variation in the relaxation parameter at low LiF contents was consistent with the weak-coupling model. The relaxation parameter exhibited a minimum at a composition which was different to that for the conductivity; resulting from the competing effects of Ba2+ and Li+ cations upon the ionic mobility.

M.Sural, A.Ghosh: Solid State Ionics, 1999, 126[3-4], 315-21