Transport Critical Current Density of Bi1.6Pb0.4Sr2Ca2Cu3O10)/Ag Superconductor Tapes with Addition of 50 and 70 nm MgO

摘要： added size 50 average particle and 70 nm were MgO nanoparticles with into Bi1.6Pb0.4Sr2Ca2Cu3O10(MgO)x/Ag superconductor tapes and sintered at 845 oC for 50 and 100 h. The effect of sintering time on the transport critical current density (Jc) was investigated. Jc of the tapes were measured in zero-field between 30 and 77 K and under magnetic fields at 77 K. The phase and microstructure of the tapes were examined by X-ray diffraction method and scanning electron microscopy, respectively. All tapes showed plate-like grains and a larger plate-like grain was observed in the tapes sintered for 100 h. Jc of the MgO added tapes was higher than those of the non-added tapes. Jc of the non-added tape sintered for 100 h was 10820 A/cm2 at 30 K and 1262 A/cm2 at 77 K. Jc of the tapes sintered for 100 h was higher than the tapes sintered for 50 h. The 50 nm MgO added tapes showed a higher Jc than the 70 nm MgO added tapes. Jc for the 100 h sintered MgO (50 nm) added tape was 22710 and 3070 A/cm2 at 30 and 77 K, respectively which are higher than that of the 100 h sintered MgO (70 nm) added tape. The improved Jc was attributed to the increase in flux pinning potential and improvement in the microstructure due to the addition of nano-sized MgO. This work showed the importance of the size of the added nanoparticles to the transport current properties of these superconductors.