Diffusion dynamics in AgI-type solid electrolytes
Abstract Some elementary features of cation motion in AgI-type solid electrolytes are discussed on the basis of experimental results. In α-AgI, quasielastic neutron scattering spectra obtained from a large single crystal reflect the anisotropy of translational diffusion via tetrahedral voids. In α-RbAg 4 I 5 , the conductivity spectrum indicates the frequent occurence of forward-backward “trial-and-error” hops among tetrahedral sites. This feature is explained in terms of a dynamic cage effect due to the Coulomb interaction between the mobile ions. Finally it is shown that the cage effect also accounts for an irregular localized motion of the cations in α-AgI observed by neutron scattering and far-infrared spectroscopy. New measurements corroborate the dispersion of the microwave conductivity of α-AgI reported earlier.