Influence of Pb addition on the superconducting properties of polycrystalline Sr0.6K0.4Fe2As2

Polycrystalline Sr0.6K0.4Fe2As2 samples with various Pb additions (0-20 wt%) were prepared using a one-step solid state reaction. X-ray diffraction analysis shows no evidence for chemical reaction between the Pb and the FeAs-based superconductor. However, the presence of the Pb can affect the microstructure and superconducting properties of the final products. The critical transition temperature Tc indicates no degradation up to 20 wt% Pb addition, and dramatic improvements of magnetic Jc and irreversibility field Hirr were observed for appropriate Pb concentration. Transport critical current property of pure and Pb-added Sr0.6K0.4Fe2As2 tapes was also measured by a four-probe technique, and a remarkable enhancement of Jc at low fields was detected for the Pb added tapes.