High critical current density and low anisotropy in textured Sr1-xKxFe2As2 tapes for high field applications

摘要

From the application point of view, large critical current densities Jc (H)for superconducting wires are required, preferably for magnetic fields higherthan 5 T. Here we show that strong c-axis textured Sr1-xKxFe2As2 tapes withnearly isotropic transport Jc were fabricated by an ex-situ powder-in-tube(PIT) process. At 4.2 K, the Jc values show extremely weak magnetic fielddependence and reach high values of 1.7x10^4 A/cm^2 at 10 T and 1.4x10^4 A/cm^2at 14 T, respectively, these values are by far the highest ever reported foriron based wires and approach the Jc level desired for practical applications.Transmission electron microscopy investigations revealed that amorphous oxidelayers at grain boundaries were significantly reduced by Sn addition whichresulted in greatly improved intergranular connectivity. Our resultsdemonstrated the strong potential of using iron based superconductors for highfield applications.