Nuclear magnetic resonance line-shapes (23Na) were measured at 125 to 909K in order to investigate Na+ ion dynamics in the polycrystalline oxide, which had a 1-dimensional structure. The line-shape comprised 3 peaks which indicated the presence of Na+ ions on 3 different Na+ sites. The motion of Na+ ions was observed above 250K, and motional averaging of the sites was complete at 390K. The temperature dependence of nuclear magnetic resonance shift was suggested to be closely correlated to the behavior of the magnetic susceptibility of the 4d electrons of Ru4+.

Na+ Ion Motion in Na3Ru4O9 - an NMR Study of 23Na Lineshape. Y.Onoda, S.H.Chung, A.Watanabe, T.Mitsuhashi: Solid State Ionics, 2000, 136-137, 365-70