1H-NMR on super-ionic conductor Tl3H(SO4)2

We have studied the proton dynamics on Tl3H(SO4)(2) from the measurements of H-1-NMR absorption lines. It was found that the NMR line width DeltaH at room temperature becomes about 20 times narrower than that at 77 K and that the NMR absorption line at room temperature shows the mixture functional form of the Gaussian and Lorentzian. These results indicate that protons migrate even at room temperature: that is, Tl3H(SO4)(2) becomes a super-ionic conductor at room temperature. From the temperature dependence of DeltaH, we have obtained the result that the phase transition at TII-III = 239 K corresponds to the super-ionic phase transition. Furthermore, we calculate the proton correlation times from the line widths and determine the activation energy of proton motion in the phase II (super-ionic phase) to be 0.33 eV This result indicates that proton migration lead to the electric conductivity in the super-ionic phase.