Extremely slow cation exchange processes in Li4SiO4 probed directly by two-time 7Li stimulated-echo nuclear magnetic resonance spectroscopy

Martin Wilkening, Paul Heitjans

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Lithium self-diffusion in the low-temperature modification of polycrystalline lithium ortho-silicate Li4SiO4 is investigated by 7Li two-time stimulated echo NMR spectroscopy. Extremely slow Li exchange processes were directly monitored between 300 and 433K by recording spin-alignment echoes as a function of mixing time varying over six decades from 10-5 to 10s. In the investigated temperature range the hopping correlation functions show biexponential behaviour. Whereas the first decay step reflects directly Li jumps between electrically different sites, the second one is simply induced by the decay of alignment order due to quadrupolar relaxation. The echo decay rates τ-1(10 1s-1≤τ-1≤104s -1), which can be identified with Li jump rates, show Arrhenius behaviour with an activation energy of 0.53(1)eV. The directly measured jump rates are in good agreement with those obtained recently by one-and two-dimensional 6Li exchange MAS NMR reported in the literature.

Original languageEnglish
Article number007
Pages (from-to)9849-9862
Number of pages14
JournalJournal of Physics Condensed Matter
Volume18
Issue number43
DOIs
Publication statusPublished - 1 Nov 2006
Externally publishedYes

    Fingerprint

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

Cite this