High transport current superconductivity in powder-in-tube Ba0.6K0.4Fe2As2 tapes at 27 tesla

TL;DR

This paper reports the development of Ba0.6K0.4Fe2As2 superconducting tapes with record-high transport critical current densities at high magnetic fields, achieved through a combined powder-in-tube and hot-press fabrication method, promising for high-field magnet applications.

Contribution

First demonstration of hot-pressed Ba-122 superconducting tapes with record-high Jc values at high magnetic fields for iron-based superconductors.

Findings

Achieved Jc of 1.5x10^5 A/cm^2 at 4.2 K and 10 T

Jc of 5.5x10^4 A/cm^2 at 27 T

Tapes exhibit high c-axis texture and low anisotropy

Abstract

The high upper critical field and low anisotropy of iron-based superconductors make them being particularly attractive for high-field applications. However, the current carrying capability needs to be enhanced by overcoming the weak-link effect between misaligned grains inside wire and tape conductors. Here we demonstrate a high transport critical current density (Jc) reaching 1.5x10^5 A/cm^2 (Ic = 437 A) at 4.2 K and 10 T in Ba0.6K0.4Fe2As2 (Ba-122) tapes prepared by a combination of conventional powder-in-tube method and optimized hot-press technique. The transport Jc measured at 4.2 K under high magnetic fields of 27 T is still on the level of 5.5x10^4 A/cm^2, which is much higher than those of low-temperature superconductors. This is the first report of hot-pressed Ba-122 superconducting tapes and these Jc values are by far the highest ever reported for iron-based superconducting wires and tapes. These high-performance tapes exhibit high degree of c-axis texture of Ba-122 grains and low anisotropy of transport Jc, showing great potential for construction of high-field superconducting magnets.