7Li NMR study of a co-ionic conductor: Lithium/sodium β-alumina

Room temperature 7Li spectra are reported for β-alumina samples with varying amounts of lithium substituted for sodium. A large dependence of the 7Li satellite (±3/2↔±1/2) position on lithium content was observed. A 91 percent-exchanged sample exhibited a thermally averaged lithium electric-field gradient of near-axial symmetry (η=0±0.04) with e2qQ=17.0±0.2 kHz. Field-dependent structure in the 1/2↔−1/2 transition was also observed.