Conduction in CsCl-Al2O3 composite solid electrolytes: Evidence for interfacial space charge

Conductivity versus temperature studies reveal that the phase transition from B2 phase (CsCl structure) to a high temperature B1 phase (NaCl structure) is suppressed in the CsCl-Al2O3 composites. However, DTA measurements on the composite samples show that both the B1↔B2 and the melting transition occurring in pure CsCl occur in the composites. Moreover, there is no shift in these transition temperatures due to dispersion of A12O3, which suggests that A12O3 remains as a separate phase in the composites. These results indicate that the conduction in the composites is controlled by a single mechanism in the temperature regimes that are above and below the transition temperature, possibly through a high-conducting interfacial space charge region.