Thermal and superconducting properties of glass–ceramic HTc BiSrCa(CuPr)O system

In this study, the glass samples with nominal composition of Bi2Sr2Ca2Cu3−xPrxO10+y, where x = 0.5, were fabricated using conventional melt quenching technique. After appropriate heat treatments, the glass–ceramic samples obtained showed a deformed and multiphase structure. While the a(=b)-axis was nearly unchanged, the c-axis was obtained to be smaller than that of the unsubstituted Bi-2223 system. From the resistance versus temperature measurements, a semiconducting type behavior down to Tc was observed. The best Tc value was obtained to be 46 K and Tzero 29 K for the sample heat treated at 1123 K (850 °C) for 60 h. The Pr-substituted Bi-2223 glass–ceramic samples showed negative thermoelectric power, indicating that the dominant carriers are electrons in the samples. “Two-band model with linear T-term” was used to analyze the TEP data. A rapid rise in thermal conductivity, κ, was obtained just below Tc. This suggests an enhancement of the quasiparticle contribution to the heat conductivity and so an increase of the quasiparticle mean free path.