The temperature dependence of the spin-lattice relaxation time of 7Li was measured in a monocrystalline sample at temperatures ranging from 450 to 770K. It was found that the results could be explained by a vacancy diffusion mechanism. The activation energies for the hopping of Li+ and Na+ vacancies were estimated to be 0.70 and 1.20eV, respectively. The ionic conductivity was measured as a function of frequency (500Hz to 20MHz), and a value of 1.59eV was deduced for ionic diffusion in the extrinsic region. These values agreed well with the corresponding values of 0.70, 1.24 and 1.74 to 1.90eV, which had been found by using nuclear magnetic resonance techniques.

T.Kanashiro, T.Yamanishi, Y.Kishimoto, T.Ohno, Y.Michihiro, K.Nobugai: Journal of the Physical Society of Japan, 1994, 63[9], 3488-93