Large Transport Critical Current Densities of Ag Sheathed   (Ba,K)Fe2As2+Ag Superconducting Wires Fabricated by an ex-situ Powder-in-Tube   (PIT) Process
  We report large transport critical current densities observed in Ag-added (Ba,K)Fe2As2 superconducting wires prepared by an ex-situ powder-in-tube (PIT) process. The wire has a simple composite structure sheathed only by Ag. A precursor bulk material prepared by a melting process was ground into powder and put into a Ag tube. The composite was then cold worked into a wire and heat treated at 850$^\circ$C for sintering. Transport critical current densities, Jc, at 4.2 K are 1.0\times104 A/cm2 (Ic = 60.7 A) in self field and 1.1\times103 A/cm2 (Ic = 6.6 A) in 10 T. These are the highest values reported so far for the Fe-based superconducting wires. 
Kazumasa Togano, Akiyoshi Matsumoto, and Hiroaki Kumakura
cond-mat.supr-con