The 7Li nuclear magnetic resonance relaxation times T1, T1ρ and T2 versus temperature were reported at 150 to 900K for Li3xLa2/3-x1/3-2xTiO3 perovskite-type fast-ionic conductors. The presence of Li+ ions of 2 kinds, with slightly differing environments, was revealed by the experiments. These ions exhibited 2 different motions: a fast one with a characteristic frequency around 100MHz at 350K and a slow one whose frequency was around 60kHz at 280K. These 2 different Li+ species could not be differentiated by means of the fast motion (only one T1 was observed in the experiments), but only by means of the slow ones (two T1ρ and two T2 were observed). These motions were attributed to Li+ motion within the A-cage of the perovskite structure formed by the O ions and to Li+ hopping between the cages, respectively. Studies performed on the 6Li nucleus clearly showed that dipolar nuclear interaction alone was responsible for Li+ relaxation. This result was at variance with what had previously been put forward for the relaxation process in these compounds.

Nuclear Magnetic Resonance Investigation of Li+-Ion Dynamics in the Perovskite Fast-Ion Conductor Li3xLa2/3-x1/3-2xTiO3. J.Emery, O.Bohnké, J.L.Fourquet, J.Y.Buzaré, P.Florian, D.Massiot: Journal of Physics - Condensed Matter, 2002, 14[3], 523-39