A new problem in the correlation of nuclear-spin relaxation and ionic conductivity in superionic glasses

M. Tatsumisago, Charles Angell, S. W. Martin

Research output: Contribution to journalArticle

74 Citations (Scopus)

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 conducting glasses, 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 conducting glasses, 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.

Original languageEnglish (US)
Pages (from-to)6968-6974
Number of pages7
JournalThe Journal of Chemical Physics
Volume97
Issue number9
StatePublished - 1992

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Ionic conductivity
Spin-lattice relaxation
spin-lattice relaxation
nuclear spin
ion currents
Ions
Glass
conductivity
glass
ions
conduction
activation energy
Activation energy
ion motion
solid electrolytes
Solid electrolytes
Relaxation processes
Lithium
Relaxation time
lithium

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

A new problem in the correlation of nuclear-spin relaxation and ionic conductivity in superionic glasses. / Tatsumisago, M.; Angell, Charles; Martin, S. W.

In: The Journal of Chemical Physics, Vol. 97, No. 9, 1992, p. 6968-6974.

Research output: Contribution to journalArticle

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