Bi2Sr2CaCu2Ox/Ag multilayer tapes with Jc(4.2K, 10T) of 500,000 A/cm2 by using PAIR process

We developed PAIR (Pre-Annealing and Intermediate Rolling) process, which is a fabrication procedure for Bi2Sr2CaCu2Ox(Bi-2212)/Ag composite tapes, in order to improve their superconducting properties. PAIR process is the combination of pre-annealing and subsequent intermediate rolling (IR) processes and is performed prior to melt-solidification process. By performing PAIR process, Bi-2212 grain alignment and intergrain connectivity are much improved and a large J(c) enhancement can be expected for Bi-2212/Ag conductors. We study the effects of pre-annealing and intermediate rolling processes on microstructure and superconducting properties of the Bi-2212/Ag multilayer tapes fabricated by the oxide-painting and lamination method. The results show that J(c) has been increased strongly by performing pre-annealing at 1133 K in oxygen (1 atm) and intermediate rolling with 25% deformation. PAIR processed samples have transport J(c)-oxide (4.2 K, 10 T) exceeding 5.0 x 10(9) A/cm(2) Whereas J(c)-oxide for the samples melt-solidified without PAIR process remains 3.0 x 10(5) A/cm(2). The enhancement of J(c) is assigned to the microstructure with high grain alignment and uniformity, as well as the improvement in grain connectivity achieved by PAIR process.