Preparation and Electric Property of Bi₂Sr₂Co₂O_y Thermoelectric Ceramics

Bi₂Sr₂Co₂O_y ceramics were prepared by sol-gel method and solid-state reactions.The phase and microstructure of the ceramics were analyzed by means of XRD and SEM.The temperature dependence of the electrical resistivity was detected with standard four probes method.The results show that the ceramics were single phase with layer microstructure homogeneous and oriented preferably to c-axis.The samples prepared by sol-gel method perform metallic-like behavior,while the semiconductor-metal transition exists in the samples prepared by solid-state reactions.