Effect of micro-structure on electrical transport properties in Ca3Co4O9 ceramics

Abstract

The different Ca3Co4O9 powders were obtained by the solid reaction and the polyacrylamide gel method. The synthesized temperature of Ca3Co4O9+δ was reduced to 933 K by the polyacrylamide gel method. The electrical properties can be effectively improved by combining polyacrylamide gel method and Spark Plasma Sintering. There are little change of resistivities with gain size changing, but resistivity is obviously influenced by oxygen stoichiometry. The phenomenon results from small polaron hopping conductive mechanism. The hopping activation energy reduce in oxygen rich atmosphere due to smaller hopping distance.