Thermoelectric Power Factor of Polycrystalline La0.75Sr0.25Co1-xMnxO3-δ Ceramics

Thermoelectric properties of polycrystalline La(0.75)Sr(0.25)Co(1-x)Mn(x)O(3-delta) (0 < x < 0.08) (LSCoO-Mn) compounds have been studied. The samples were grown by solid-state reaction method; their transport properties were studied in the temperature range between 100 and 290K, as a function of temperature and the manganese content. The Seebeck coefficient (S) is positive over the measured temperature range and its magnitude increases with the manganese content up to values close to 160 mu V/K. The electrical resistivity (rho) goes from metallic to semiconducting behavior as the Mn level increases, at room temperature, rho(T) exhibit values less than 4m Omega-cm. From S(T), rho(T) and kappa(T) data, the thermoelectric power factor and the figure of merit were determined. These performance parameters reach maximum values around 18 mu W/K(2)-cm and 0.2, respectively. The observed behavior in the transport properties become these compounds potential thermoelectric materials, which could be used in thermoelectric applications.