Thermal Conductivity and Thermoelectric Power of Potassium and Sodium-Substituted Bi-2212 Superconductor Prepared by PEI Technique

摘要: In the present study, thermal conductivity (κ − T), thermoelectric power (S and figure of merit (ZT) measurements from room temperature down to 20 K polycrystalline Bi2Sr2Ca1−xNaxCu2O8+y Bi2Sr2Ca1−xKxCu2O8+y superconductors prepared by a polymer solution technique using polyethyleneimine, PEI, have been carried out. The power, S(T), samples both negative (at high T) positive values low are found increase with decreasing temperature, reaching their maximum (peaks) around Tc dropping rapidly zero below Tc. Na substitutions also considerable effect on conductivity, κ. Namely, increasing concentration magnitude κ is decreased, but for substitution, drastically increased x = 0.75.