Thermal properties of La0.5Sr0.5Co1−xNixO3−δ ceramics using photopyroelectric technique

La 0.5 Sr 0.5 Co 1−x Ni x O 3−δ (0⩽ x ⩽0.6) ceramics were prepared using a conventional solid-state ceramic route. The thermal properties—thermal conductivity and heat capacity—of these ceramics were measured by the photopyroelectric technique. The thermal conductivity was found to increase with increasing Ni content. These materials were also found to exhibit a metallic-type variation of thermal conductivity with temperature, and no metal-insulator (M-I) transition was found to occur in any of the samples prepared by this route. However, a M-I transition was found to occur in La0.5Sr0.5CoO3−δ samples prepared by hot pressing. The difference is attributed to variations in oxygen content in the samples.