Transport study of newly synthesized polycrystalline Sr1−xKxPbO3−δ solid solutions

• Published in: Journal of alloys and compounds Vol. 346; no. 1-2; pp. 17 - 23
• Main Authors: Drozd, Vadim A., Gabovich, Alexander M., Pękała, Marek, Boychuk, Valery N., Moiseev, Dmitry P., Nedilko, Sergey A.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 18.11.2002; Elsevier
• Subjects: Ceramics; Chemical synthesis; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conductivity phenomena in semiconductors and insulators; Electrical transport; Electronic transport in condensed matter; Exact sciences and technology; Oxide materials; Physics; Thermoelectric; Thermoelectric and thermomagnetic effects; Thermoelectric; Ceramics; Chemical synthesis; Oxide materials; Electrical transport; Inorganic compounds; Electrical conductivity; Charge carriers; Metal-insulator transition; Tunnel effect; Polycrystals; Lead oxides; Experimental study; Electron localization; Strontium oxides; Energy gap; Electronic structure; Degenerate state; Solid solutions; Thermoelectric power; Potassium oxides; Chemical composition; Transport processes; Quaternary compounds
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/S0925-8388(02)00497-8

New ceramics of Sr1−xKxPbO3−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<300 K. For low T, the thermal resistivity coefficients dρ/dT 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 SrPbO3 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.