CONTRIBUTION OF CU+ IONS DISSOLVED IN AGBR TO THE TRANSPORT-PROPERTIES

The electrical conductivities and transport numbers of the solid solution (AgxCu1-x)Br have been measured as a function of temperature and composition. An attempt to determine the partial conductivities and activation energies for mobile ions is made from these results. The estimated enthalpies of formation and migration for Ag+ and Cu+ ions show an exponential decrease with increasing amount of Cu+ into AgBr lattice. The lowering is attributable to the lattice expansion by the occupation of Cu+ at the interstitial sites. The effect of exponential decrease in the formation enthalpy is to allow a rapid growth in the concentration of interstitials around the composition of chi congruent-to 0.85. This result is consistent with structural data derived by X-ray diffraction.