Significant enhancement of transport Jc in Cu/Ag-sheathed (Ba,K)Fe2As2 superconducting tapes by pre-composite technique

Abstract

Iron-based superconductors (IBSs) have received extensive attention in superconductivity mechanisms and high-field applications based on their ultra-high upper critical fields and low anisotropy. A major goal in the application research of IBSs is the fabrication of superconducting wires and tapes with high critical current density (Jc) and low cost. The use of Cu/Ag composite sheath can reduce the use of expensive silver, thereby reducing the cost of the tapes. In this paper, (Ba,K)Fe2As2 (Ba-122) tapes with Cu/Ag composite sheath were fabricated by a pre-composite process, which provides a feasible method for fabricating high-performance iron-based superconducting wires and tapes. Pre-composite tapes sintered at 750°C for 3 h achieved a high Jc of 6.2 × 104 A cm−2 at 10 T and 4.2 K. It is found that the high-density superconducting cores, large-size grains and uniform element distribution are the major causes of the high Jc. The results suggest that the low-cost Ba-122 tapes with pre-composite Cu/Ag sheath have great practical application prospect in the future.