Transport Critical Current Density of Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O₁₀)/Ag Superconductor Tapes with Addition of 50 and 70 nm MgO

摘要

MgO nanoparticles with average particle size 50 and 70 nm were added intoBi1.6Pb0.4Sr2Ca2Cu3O10(MgO)x/Ag superconductor tapes and sintered at 845 C for 50 and 100 h. Theeffect of sintering time on the transport critical current density (Jc) was investigated. Jc of the tapeswere measured in zero-field between 30 and 77 K and under magnetic fields at 77 K. The phase andmicrostructure of the tapes were examined by X-ray diffraction method and scanning electronmicroscopy, respectively. All tapes showed plate-like grains and a larger plate-like grain was observedin the tapes sintered for 100 h. Jc of the MgO added tapes was higher than those of the non-added2 2 tapes. Jc of the non-added tape sintered for 100 h was 10820 A/cm at 30 K and 1262 A/cm at 77 K.Jc of the tapes sintered for 100 h was higher than the tapes sintered for 50 h. The 50 nm MgO addedtapes showed a higher Jc than the 70 nm MgO added tapes. Jc for the 100 h sintered MgO (50 nm)2 added tape was 22710 and 3070 A/cm at 30 and 77 K, respectively which are higher than that of the100 h sintered MgO (70 nm) added tape. The improved Jc was attributed to the increase in flux pinningpotential and improvement in the microstructure due to the addition of nano-sized MgO. This workshowed the importance of the size of the added nanoparticles to the transport current properties ofthese superconductors.