This paper presents the synthesis and characterization of Bi2Sr2Ca2Cu3O8+x superconducting nanowires. Bi2Sr2Ca2Cu3O8+x nanowires with Tc = 68 K were synthesized using the electrospinning process employing sol–gel precursors. A sol–gel methodology was used to obtain a homogeneous PVP solution containing Bi, Sr, Ca, and Cu oxalates. Samples were heat-treated at 120 °C to remove excess moisture, and then at 850 °C in box furnace. Bulk sample was also prepared using coprecipitation method for comparison. Based on XRD, the nanowire sample showed minimal Bi-2223 phases and apparent Bi-2212 phases. The morphology, microstructure, and crystal structure of these nanowires were examined using field emission scanning electron microscopy (FESEM) to reveal a rectangular morphology having typical wire thickness in the range of 150–1000 nm. Electrospun Bi-2223 were grinded and pressed at 0.9 GPa into pellets. DC measurements were conducted to investigate the critical transition temperature (Tc) of Bi-2223 nanowires and to compare their magnetic properties to those of coprecipitated Bi-2223 pellets. The Tc for the bulk sample is observed at 101 K and electrospun Bi-2223 at 68 K. Coprecipitated Bi-2223 was added with Pb whereas electrospun Bi-2223 does not employ Pb. These results point to the existence of utilizing of the substitution of Pb with Bi; Bi-2223 phases in pressed nanowire are less, and the potential of using electrospinning to synthesis functional Bi-2233 superconductors.

Effect of complex magnetic oxide Co0.5Ni0.5Fe2O4 (CNFO) nanoparticles addition in (Bi1.6Pb0.4)Sr2Ca2Cu3O10 (Bi-2223) superconductor tapes was investigated. Ultrafine Bi-2223 powder precursor was prepared via co-precipitation method and was added with 0.01 – 0.05 wt.% Co0.5Ni0.5Fe2O4 nanoparticles during the final heating stage. The sample with 0.01 wt.% addition, Bi-2223(CNFO)0.01 was found to have the highest critical current density, Jc. This sample were then chosen to be fabricated into Ag-sheathed superconductor tapes using the powder-in-tube (PIT) method. The tapes were sintered for 50 and 100 h at 845 °C. The phase, microstructure and Jc of the samples were determined by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and four point probe, respectively. Jc of Ag-sheathed Bi-2223(CNFO)0.01 tapes sintered for 100 h was 19830 A/cm2 at 30 K and 3970 A/cm2 at 77 K compared to tapes without addition which showed a much lower Jc(6370 A/cm2 at 30 K). This study showed that CNFO nanoparticles could act as an effective flux pinning centers to enhance the critical current density in the Bi-2223 superconductor.