Fabrication of high-performance (Ba,K)Fe2As2 superconducting wires by powder-in-tube method

(Ba,K)Fe2As2 superconducting wires have been fabricated by ex-situ powder-in-tube method. In addition to the pure (Ba,K)Fe2As2 wires, silver powder was also used as a chemical addition to improve the performance of these superconducting wires. The transport critical current density (Jc) has reached 1.3×104 A/cm2 at 4.2 K under self field in the wire with Ag addition. The self-field Jc is the highest among all the reported Fe-based superconducting wires so far. We have also performed magneto-optical imaging to this (Ba,K)Fe2As2 superconducting wire with Ag addition, and intragranular Jc of 6.0×104 A/cm2 at 20 K is obtained, which is similar to the estimation from M-H measurement.