Effect of metal (Zn/In/Pb) additions on the microstructures and superconducting properties of Sr1 - xKxFe2As2 tapes

Zn-, In- and Pb-added Ag-sheathed Sr1 - xKxFe2As2 tapes were fabricated through the powder-in-tube method. All added tapes are found to have increased transport J(c) at 4.2 K in fields up to 14 T than the pure samples. The best J(c) result has been achieved in Zn-added tapes. Microstructure investigations reveal that Zn addition can improve both phase uniformity and grain connectivity of Sr1 - xKxFe2As2, thus resulting in higher J(c). Furthermore, the critical temperature for the added tapes decreased very slightly (only about 0.4 K). The role of Zn addition may be beneficial in promoting a large range of applications for iron-pnictide conductors. (C) 2015 Elsevier Ltd. All rights reserved.