Document Type

Article

Publication Date

1992

Journal or Book Title

Journal of Chemical Physics

Volume

97

Issue

9

First Page

6968

Last Page

6974

DOI

10.1063/1.463658

Abstract

Following the recent resolution of the longstanding problem of reconciling constant frequency nuclear‐spin lattice relaxation (SLR) activation energies and d.c. conductivity activity energies in ion conductingglasses, we point out a new problem which seems not to have been discussed previously. We report conductivity data measured at a series of fixed frequencies and variable temperatures on a lithium chloroborate glass and compare them with SLR data on identically prepared samples, also using different fixed frequencies. While phenomenological similarities due to comparable departures from exponential relaxation are found in each case, pronounced differences in the most probable relaxation times themselves are observed. The conductivity relaxation at 500 K occurs on a time scale shorter by some 2 orders of magnitude than the 7Li SLR correlation, and has a significantly lower activation energy. We show from a literature review that this distinction is a common but unreported finding for highly decoupled (fast‐ion conducting) systems, and that an inverse relationship is found in supercoupled salt/polymer ‘‘solid’’ electrolytes. In fast‐ion conductingglasses, the slower SLR process would imply special features in the fast‐ion motion which permit spin correlations to survive many more successive ion displacements than previously expected. It is conjectured that the SLR in superionic glasses depends on the existence of a class of low‐lying traps infrequently visited by migrating ions.

Comments

The following article appeared in JJ. Chem. Phys. 97, 6968 (1992) and may be found at http://dx.doi.org/10.1063/1.463658

Rights

Copyright 1992 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

Copyright Owner

American Institute of Physics

Language

en

File Format

application/pdf

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