The migration of protons in single crystals of a fast protonic conductor with the composition, (NH4+)(H3O+)0.85Al10.15O17, was investigated at 336 to 451K by using a pulsed field gradient nuclear magnetic resonance technique. The temperature dependence of the proton diffusion was described by:

D (cm2/s) = 6.76 x 10-5 exp[-0.20(eV)/kT]

Y.T.Tsai, S.Smoot, D.H.Whitmore, J.C.Tarczon, W.P.Halperin: Solid State Ionics, 1983, 9-10, 1033-40