| Abstract Scope |
Cooperative motion of correlated ions has long been known to affect the conductivity of solid-state ion conductors. But a detailed understanding of correlated diffusion, microscopic diffusion pathways, residence times, activation energies, and the interplay between mobile ions and local relaxations of the surrounding lattice, required for optimizing the ionic conductivity, remains lacking. Quasi-elastic neutron scattering (QENS) and single crystal diffuse scattering can provide detailed insight into these local correlations and their dynamics. Such measurements can now be performed on single crystals providing coverage over four-dimensional momentum and energy transfer space, allowing detailed, quantitative comparison to jump diffusion models, such as the Chudley-Elliot model. We will discuss our analysis of 4D-QENS and diffuse scattering data from SrCl2, which reveals de Gennes narrowing of linewidths in regions of strong coherent scattering and provides evidence of the metastability of interstitial sites along the pathways.
Work supported by the U.S. DOE, BES, DMSE |