The dielectric/impedance spectra of Rb3H(SeO4)2 crystals was studied in room- and high-temperature phases in wide frequency range. The original method of calculation of the distribution function g(τ) of relaxation times was applied for the ionic conducting materials. The high-frequency impedance spectrum splits into two relaxors by one order of magnitude at high temperatures. The calculated mean time for fast relaxation was 5.5 x 10−9s at Tc = 450K. The slower relaxation time was about 10 times longer in the superionic phase. The difference between the faster and the slower relaxation times at high temperatures corresponds to the proportion of the rate of the proton transfer within H bond and that of the rotational hopping. The appearance of the two peaks in g(τ) confirms the two-stage transport mechanism in the hydrogen-bonded system and supports the theoretical suggestions of the important role of interproton interactions and the polaronic effect in superionic phase transition mechanism.

Conductivity Properties of Rb3H(SeO4)2 Crystals in the Region of Superionic Phase Transition. R.Sobiestianskas, J.Banys, J.Grigas, A.Pawłowski: Solid State Ionics, 2008, 179[1-6], 213-7