Muon spin relaxation study of protonic superionic conductor CsHSO4

The protonic superionic conductor CsHSO4 has been studied by μSR over the range of temperatures 15-440 K. The first successful observation of superionic phase transition by the μSR method is reported. A spasmodic change in relaxation rate and asymmetry was observed as the transition temperature was approached. There are no any remarkable differences in the relaxation rate between deuterated and protonated samples in the temperature range 15-290 K. Asymmetry revealed in isotope effect. The temperature dependence and isotope effect for asymmetry may testify the formation of muonium fraction in the sample. Together with the published NMR results the obtained μSR data confirm the fact that the high ionic conductivity in CsHSO4 is the result of high monility of protons in a superionic phase. 9 refs.; 5 figs