Giant magnetothermal conductivity and giant magnetothermopower in granular Co-Ag solids

Measurements on the thermal conductivity and thermoelectric power of granular Co₂₀Ag₈₀ solids annealed at various temperatures are reported. Thermal conductivity is dominated by its electronic contribution, and the Wiedemann-Franz law to found to be satisfied between 2 K and 300 K, which is mainly ascribed to dominant large-angle elastic scattering processes. The thermoelectric power is negative, and is considerably reduced by the annealing process. Giant magnetothermal conductivity and giant magnetothermopower are found to be correlated with the giant magnetoresistance