Nanoparticles as flux pinning centre in bulk and Ag sheathed Bi_(1.6)Pb_(0.4)Sr_2Ca_2Cu_3O_(10) high temperature superconductor tapes

摘要

The enhancement of critical current density in Bi_(1.6)Pb_(0.4)Sr_2Ca_2Cu_3O_(10) (Bi2223) superconductor in bulk and tape form through the addition of Cr_2O_3 (6.5 nm) and Fe_3O_4 (40 nm) nanoparticles is reported. The superconductor powders were prepared by using the coprecipitation technique. The powder in tube method was used to fabricate the Ag sheathed high temperature superconductor tapes with addition of various weight per cent of nanoparticle. The effects of these nanoparticles additions on the transition temperature T_c and transport critical current density J_c were studied. All nanoparticles added samples showed higher J_c compared to the non-added samples. When magnetic nanoparticles (Fe_3O_4) are employed, a smaller amount is required to optimise T_c and J_c. This study shows that nanoparticles can act as effective pinning centres leading to the enhancement of J_c in the Bi2223 system.