Search for p-type oxide thermoelectrics - cobaltites

The thermal conductivity, thermoelectric power, electrical resistivity and magnetization of the 3D perovskites Ln/sub 1-x/AE/sub X/CoO/sub 3/ (Ln=La,Y and AE=Ca and Ba) and the low dimensional Ca/sub 3/Co/sub 2/O/sub 6/ and Ca/sub 3/Co/sub 4/O/sub 9/ cobaltites were measured in a wide temperature range up to 1000 K. As a novelty we demonstrate the prospective high power factor of the. Y/sub 0.9/Ca/sub 0.1/CoO/sub 3/ at high temperatures and, simultaneously, that in the La/sub 1-X/AE/sub X/CoO/sub 3/ system the maximum Z and P values are observed at the phase boundary between the FM and SG state at X/spl sim/0.1 and exceed that reported for layered cobaltite ceramics.