Improvement of Jc and Grain Alignment of Bi-2212/Ag Multilayer Tapes by Pre-Annealing and Intermediate Rolling Process

The high transport critical current density (Jc) > 500 kA/cm2 at 4.2 K, 10 T is obtained in the Bi-2212/Ag multilayer tapes fabricated by using PAIR (Pre-Annealing and Intermediate Rolling) and melt-solidification process. This Jc value is twice higher than existing high-quality Bi-2212/Ag tapes (250 kA/cm2). By applying PAIR process to Bi-2212/Ag tapes, Bi-2212 grain alignment is much improved and a large Jc enhancement is achieved. Jc has been increased strongly by performing pre-annealing at 840°C in oxygen (1 atm) and intermediate rolling with 25% deformation.