Transport study of newly synthesized polycrystalline Sr1−K PbO3− solid solutions

New ceramics of Sr 1− x K x PbO 3− δ with x =0, 0.05, 0.1, 0.15 and 0.2 were synthesized and analyzed. Temperature, T , variations of resistivity, ρ , and thermoelectric power, S , were measured for 20 T T , the thermal resistivity coefficients d ρ /d T for all compositions were found to be negative, which suggests localization of current carriers or the appearance of a dielectric gap in the electron structure. The analysis of the ρ ( T ) curve shows that the electrical conduction has at least a substantial contribution from the tunneling processes at the grain boundaries. The thermoelectric power S is negative for all compositions and for all T , thus indicating electron-like conduction. The collection of data demonstrates that the parent substance SrPbO 3 is on the verge of the metal–insulator transition and different kinds of doping may substantially change the transport properties and the degree of current carrier degeneracy. The system seems to be promising as a building block for new superconducting families.