PROTON AND DEUTERON CONDUCTIVITY IN CSHSO4 AND CSDSO4 BY IN-SITU ISOTOPIC EXCHANGE

The protonic conductivity of CsHSO4 and CsDSO4 was measured with in si tu isotopic exchange using van der Pauw and 2-electrode geometries for the high- and low-temperature phases, respectively. The proton/deuter on conductivity ratio of around 2.3 in the high temperature phase is a result mainly of a 0.02 eV higher activation energy of deuteron condu ctivity, assigned to a difference in zero-point energy. The low temper ature phases exhibited no large isotope effects and hence no indicatio ns of proton tunneling.