High transport Jc in 7-filament Cu/Ag sheathed Ba0.6K0.4Fe2As2 tapes manufactured by ambient pressure sintering

Abstract

In regard to iron-based superconductors (IBS), the multi-filament Cu/Ag composite sheathed Ba-122 tape is particularly attractive for industrial high-field applications owing to its prominent properties. By a cost-effective and scalable way, ambient pressure sintering, a high transport critical current density (Jc) of 7-filament Cu/Ag sheathed Ba-122 tapes reached 4.5 × 104 A cm−2 at 4.2 K and 10 T, whose corresponding engineering critical current density (Je) has achieved to 104 A cm−2. An optimized powder-in-tube (PIT) method was adopted aiming at overcoming the difficulty of ambient pressure sintering to obtain high-density superconducting core and grain alignment. Improvements in the manufacturing process, such as drawing without intermediate annealing and rolling from larger initial diameter to thinner tapes, have resulted in high grain connectivity and good c-axis texture, which are the major factors contributing to high Jc. Our results demonstrate that the ambient pressure sintering process is a viable method to fabricate long-length multifilamentary Cu/Ag composite sheathed IBS tapes with high Jc for practical high-field applications.