CONNECTION BETWEEN NMR RELAXATION AND ELECTRICAL-CONDUCTIVITY FROM DISTRIBUTIONS OF ACTIVATION-ENERGIES OF IONIC MOTION IN SOME FAST-ION CONDUCTORS

The Li-7 nuclear magnetic resonance (NMR) spin-lattice relaxation and the electrical conductivity in the fast-ion conducting glass 0.56 Li2S + 0.44 SiS2 have been discussed in an earlier study using models of L i ionic motions with distributions of activation energies representing the disordered structure of glasses. Good fits to the observed NMR re laxation were obtained with a Gaussian distribution. It is shown how t he complex conductivity and the related dielectric properties can be d erived in the continuous time random walk model from the same distribu tion truncated at a proposed percolation limit. Local percolation and conductivity are possible at higher frequencies, so then the limit and the average correlation time must be scaled down. This model explains the differences between the time correlation functions derived from t he two effects. The same model fits the conductivity and NMR data for a 0.6LiCl + 0.7Li(2)O + B2O3 glass.