The study of the lithium ion motion in β-alumina single crystal by NMR spectroscopy

80% and 93% Li β-alumina single crystals are prepared from Na β-alumina by ion exchange method. Temperature dependent T1 relaxation data for both the samples indicates the presence of a local motion of Li ion in β-alumina crystal. T1 relaxation data of 23Na in Na β-alumina was also studied and compared with Li β-alumina. Temperature dependent quadrupole interaction was observed for 7Li in β-alumina crystal. A simple model suggested that, an out of plane position of Li ion may be possible with small energy imbalance which corresponds to the activation energy for local motion of Li ion. The T1 relaxation data and the quadrupole data also indicate that mixed alkali effect might be present in the microscopic scale.