Fabrication of Bi_2Sr_2CaCu_2O_x/Ag tapes with J_c(4.2K, 10T) > 300,000 A/cm~2 by using PAIR process

摘要

We developed PAIR process, which is a fabrication procedure of Bi_2Sr_2CaCu_2O_x (Bi-2212)/Ag composite tapes, in order to improve superconducting properties. PAIR process is the combination of pre-annealing (PA) and intermediate rolling (IR) processes and is performed prior to melt-solidification process. By performing PAIR process, Bi-2212 grain alignment and intergrain connectivity are improved much and J_c of Bi-2212/Ag conductor is enhanced. Effects of PA and IR processes on microstructure and superconducting properties of the Bi-2212/Ag multilayer tapes fabricated by the oxide-painting method have been studied. The results show that J_c has been increased strongly by performing pre-annealing at 800～880 °C and intermediate rolling with > 25% deformation. Transport J_c (4.2 K, 10 T) of 3.0-3.3 × 10~5 A/cm~2 is obtained for PAIR processed samples. Whereas J_c for the samples melt-solidified without PAIR process remains 1.0-1.6 × 10~5 A/cm~2. The enhancement of J_c is assigned to the microstructure with high grain alignment and uniformity achieved by PAIR process.