Proton pseudoglass-to-fast-ion-conductor phase transition in CsHSO4

The temperature dependences of the proton-magnetization spin-lattice recovery functions after a saturating pulse sequence were measured in phases I, II, and III of powdered CsHSO4, and the corresponding stretched exponents and the proton T-1, T-1p, and T-2 parameters were determined. The recovery of the proton magnetization in the spin-lattice relaxation time experiment is nonexponential in phases I and II, but becomes monoexponential in the high-temperature fast-ion conducting phase m. The observed value of the stretched exponent alpha similar to 0.5 in phases I and II proves the existence of a local-polarization distribution function characteristic for orientational glasses and the presence of random fields or random bonds.