High J_c Bi-2212/Ag Multilayer Tape Conductor Prepared by a Coating Method

Abstract

The PAIR process is well known as an effective technique for achieving dense superconducting layers, resulting in highly aligned microstructure and J_c exceeding 500kA/cm² at 4.2K and 10T. In order to apply this process to a long length tape conductor, many factors had to be optimized such as residual carbon content, oxide layer thickness, and intermediate rolling reduction. We successfully fabricated 100m-class Bi-2212 multilayer tapes using the PAIR process and, at 4.2K, obtained 710kA/cm² and 350kA/cm²in self-field and 10T, respectively. The tape could be bent without I_c degradation to a diameter of 51mm, which corresponded to a bending strain of 0.6%. No J_c degradation was observed until a tensile strain of 0.2% was applied. We fabricated three coils by using a react & wind technique and tested them in high fields at 4.2K and higher by using refrigerator-cooling.