Evidence for proton conduction below superionic transition on Rb3H(SeO4)2

Measurements of thermoelectric power have been performed below a superionic transition on Rb3H(SeO4)2. The thermoelectric power S indicated the positive sign above about 350 K. This fact indicates that the majority carriers are protons. From this result, it was found that the electrical conduction below the superionic transition (Tc=449 K) is caused by protons. Moreover, from the temperature dependence of S, the activation energy for proton motion below Tc is determined to be 0.45 eV.