Nonstandard relaxation behavior in ionically conducting materials

We investigate by Monte Carlo simulations the diffusion of ions in ordered and structurally disordered lattices, where the Coulomb interaction between the mobile ions is explicitly taken into account. Results for tracer diffusion, conductivity, the diffusion-induced spin-lattice relaxation rate, and the incoherent intermediate scattering function are discussed in detail. It is shown that the presence of both disorder and Coulomb interactions leads to the typical deviations from the standard behavior of the relevant transport quantities (non-BPP, where BPP indicates Bloembergen, Purcell, and Pound behavior of the spin-lattice relaxation rate, strong dispersion of the conductivity, nonexponential decay of relaxation functions, etc.) that are experimentally observed in a wide class of ion-conducting materials.