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

TL;DR

This paper reports the fabrication of textured Sr1-xKxFe2As2 superconducting tapes with high critical current densities and low anisotropy, suitable for high magnetic field applications, achieved through an ex-situ PIT process and Sn addition.

Contribution

The study introduces a method to produce highly textured iron-based superconductor tapes with record-high Jc values and improved grain boundary connectivity for practical high-field use.

Findings

Achieved critical current densities of 1.7x10^4 A/cm^2 at 10 T and 1.4x10^4 A/cm^2 at 14 T at 4.2 K.

Reduced amorphous oxide layers at grain boundaries via Sn addition, enhancing intergranular connectivity.

Demonstrated potential of iron-based superconductors for high magnetic field applications.

Abstract

From the application point of view, large critical current densities Jc (H) for superconducting wires are required, preferably for magnetic fields higher than 5 T. Here we show that strong c-axis textured Sr1-xKxFe2As2 tapes with nearly 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 field dependence and reach high values of 1.7x10^4 A/cm^2 at 10 T and 1.4x10^4 A/cm^2 at 14 T, respectively, these values are by far the highest ever reported for iron based wires and approach the Jc level desired for practical applications. Transmission electron microscopy investigations revealed that amorphous oxide layers at grain boundaries were significantly reduced by Sn addition which resulted in greatly improved intergranular connectivity. Our results demonstrated the strong potential of using iron based superconductors for high field applications.