Role of zirconia nanoparticles on microstructure, excess conductivity and pinning mechanism of BSCCO superconductor ceramics.

Using the solid-state reaction process, we prepared (Bi,Pb)2Sr2Ca2Cu3O10-δ (Bi-2223 for brevity) ceramics with the addition of zirconium dioxide (ZrO2) nanoparticles. The proportion x of ZrO2 per the total masse of superconductor ranged from 0 wt.% to 0.2 wt.%. We report the intragrain critical current density (Jc), pinning mechanisms, and thermal fluctuations induced excess conductivity. Employing numerous characterization techniques, combining X-rays diffraction, electrical transport measurements, scanning and transmission electron microscopes (SEM and TEM), and DC magnetization hysteresis measurements, we find that the ceramic sintered with 0.1 wt.% ZrO2 nanoparticle showed the best superconducting performance. From the analysis of excess conductivity using Aslamazov–Larkin model, we assessed the crossover temperatures between different regimes of conductivity, the penetration depth, the coherence length, as well as the upper and the lower critical magnetic fields (Bc1, Bc2) at zero kelvin for all the ceramics. Critical current density versus temperature deduced from magnetization measurement is raised by NP-ZrO2 addition. Thereby, NP-ZrO2 strengthened the role of δl pinning cores and enhanced the flux pinning ability. [ABSTRACT FROM AUTHOR]