Ionic diffusion in superionic silver compounds

The diffusion constants of impurities, Cd++ and In+++ ions as well as the mobile Ag+ ions were measured in superionic α-Ag2S, α-Ag2Se and α-Ag3SI with the α-AgI structure using tracers, 109Cd, 111In and sup(106m)Ag. Unexpectedly, high mobilities were observed also for the multivalent impurity ions. The obtained diffusion constants of the Ag+ ions in α-Ag2S and α-Ag2Se are in good agreement with the reported values. It was concluded from the mobile ion dependence of activation energy for diffusion that in addition to the cation-anion and the electronic polarization, the repulsive and the cation-cation interaction play an important role in the interionic potential. (author)