Excess conductivity analysis of BiPb-2223 superconductor added with (Al2O3–15wt% ZrO2) nanopowders

Abstract

Abstract Weak flux pinning and weak intergranular coupling are the main constraints of the Bi1.6Pb0.4Sr2Ca2Cu3O10+δ (BiPb-2223) superconductor that restrict its practical applications. It has been shown that introducing artificial pinning centers could enhance flux pinning capability in high-temperature superconductors. In this work, the excess conductivity analyses used to study the effects of Al2O3–15 wt% ZrO2 (AlZr) nanocomposite on the superconducting properties of the BiPb-2223 phase. A series of (BiPb-2223)1−x/(AlZr)x composite samples (0.0 wt% ≤ x ≤ 1 wt%) were synthesized. The XRD results and SEM micrographs showed that adding AlZr nanocomposite up to 0.5 wt% improves the Bi1.6Pb0.4Sr2Ca2Cu3O10+δ phase formation and intergranular coupling. The excess conductivity analyses showed that the Fermi energy EF, Fermi velocity VF, and coherence length along the c axis ξc(0) decrease with increasing the amount of the AlZr nanocomposite. the ξc(0) value decreases from 3.68 Å for AlZr free sample to 2.70 Å for x = 1.0 wt%. Moreover, different superconducting critical parameters, including lower and upper critical magnetic fields (Bc1(0) and Bc2(0)), and critical current density (Jc(0)) are estimated by the Ginsberg-Landau theory. Obtained values indicated a remarkable enhancement in the mentioned critical parameters by adding the AlZr nanocomposite. The Jc(0) value enhances from 1.4×103 A/cm2 for AlZr free sample to 3.5×103 A/cm2 for the sample with 1.0 wt% additives, which shows that the Jc(0) is improved by about 150%. The obtained values also show that the critical magnetic fields are improved by about 80% by adding the 1.0 wt% AlZr nanocomposite. The improvement of the superconducting parameters most likely attributes to the the flux pinning capability and intergranular coupling enhancment.