SEMIEMPIRICAL MODEL FOR THE ELECTRICAL-PROPERTIES OF LA1-XCAXCOO3

A semiempirical model of the Seebeck coefficient for a small polaron h opping conductor is presented. The population of small polarons is all owed to change as a function of temperature via the mechanism of charg e disproportionation. The energy required for polaron formation by the disproportionation mechanism is modeled as screened by a Coulomb inte raction with nearby small polarons. The charge carrier site occupancie s generated by the model are used to successfully predict the electric al conductivity and Seebeck coefficient for compositions in the La1-xC axCoO3 system. Cobalt ion valence populations predicted by the model a re used to calculate effective paramagnetic moments for LaCoO3, which are favorably compared to those found experimentally.