Silver ionic and electronic conductivity in Ag9GaS6

Abstract

Electrical measurements on the mixed ionic, electronic conductor Ag9GaS6, which undergoes a phase transition at 303 K, were performed. The silver ionic conductivity in the low-temperature α-form measured using an ionic 4-probe method, is given by σT = 4.3 × 106 exp [(-29.8kJ/mol)/ RT] S m-1 K. The establishment of a fixed, reproducible thermodynamic state in this three-component, single-phase material is discussed. Experiments with Ag9GaS6 equilibrated with Ag + Ag2S and S + Ag2S revealed n-type conductivity in both equilibrium states. The electronic conductivity of β-Ag9GaS6 equilibrated with Ag + Ag2S is given by σ = 1.2 × 105 exp[(-30.4 kJ/mol)/RT] S m-1. The electron density and Hall mobility were determined from van der Pauw and Hall effect measurements.