Electrothermal performance and growth of single phase in barium doped Bi-2223 high-Tc superconductors

Abstract

Solid state reaction method was used to synthesize the high-Tc superconducting material with nominal composition Bi1.6Pb0.4Sr1.6Ba0.4Ca2Cu3Oy. This paper investigates the associations among macroscopic physical properties and features at atomic level for the prepared samples. The samples were preliminary analyzed by dc electrical resistivity and ac magnetic susceptibility. After that thermal transport, electrothermal conductivity and thermoelectric properties all as a function of temperature (from room down to liquid nitrogen temperature) were measured. X-ray diffraction studies were also done for structural analysis. All the above measurements showed that in the samples, there exists almost a single high- Tc phase with Tc,0 ∼ 110±1K. The lattice constants of the material were determined by indexing the diffraction peaks. Samples were investigated for thermal transport properties, i.e. thermal conductivity, thermal diffusivity and heat capacity per unit volume. Thermal transport properties were measured by a newly developed and calibrated Advantageous Transient Plane Source method. Simultaneous measurement of thermal conductivity and thermal diffusivity made it possible to estimate specific heat and the Debye temperature TD. Thermoelectric power (Seebeck Coefficient) and electrothermal conductivity were also measured with a recently developed and attuned apparatus. Using dc electrical resistivity, thermal conductivity and thermoelectric power, the Figure of merit factor was also calculated.