PROTON GLASS BEHAVIOR AND HOPPING CONDUCTIVITY IN SOLID-SOLUTIONS OF ANTIFERROELECTRIC BETAINE PHOSPHATE AND FERROELECTRIC BETAINE PHOSPHITE

Measurements of the dielectric permittivity are reported for solid solutions of antiferroelectric betaine phosphate and ferroelectric betaine phosphite at frequencies 10(-2) Hz < v < 10(9) Hz and temperatures 2 K < T < 300 K. In these compounds the inorganic components are linked by hydrogen bonds to one-dimensional chains. The mixed crystal with a phosphate concentration x = 0.95 orders antiferroelectrically at T(c) = 79 K. For T > T(c) the dielectric response is dominated by ac and dc conduction. The 40% sample exhibits pure relaxational behavior indicative of a transition into an orientational glass state.