Large transport Jc in Cu-sheathed Sr0.6K0.4Fe2As2 superconducting tape conductors

TL;DR

This study demonstrates a rapid hot pressing method to produce Cu-sheathed Sr0.6K0.4Fe2As2 superconducting tapes with exceptionally high transport Jc, overcoming previous diffusion issues and enabling practical applications.

Contribution

A simple hot pressing process at 800°C for 30 minutes yields high-quality Cu-sheathed Sr-122 tapes with record high in-field Jc performance.

Findings

Achieved transport Jc of 3.1x10^4 A/cm^2 at 10 T and 2.7x10^4 A/cm^2 at 14 T at 4.2 K.

Rapid fabrication effectively prevents Cu diffusion into the superconducting core.

Highest in-field Jc reported for Cu-sheathed high-Tc conductors.

Abstract

Copper sheath is the first choice for manufacturing high-Tc superconducting wires and tapes because of its high electrical and thermal conductivities, low cost and good mechanical properties. However, Cu can easily react with superconducting cores, such as BSCCO, MgB2 and pnictides, during high-temperature sintering process and therefore drastically decrease the transport Jc. Here, we report the fabrication of Cu-sheathed Sr1-xKxFe2As2 tapes with superior Jc performance using a simple hot pressing method that is capable of eliminating the lengthy high-temperature sintering required by conventional process. We obtained high-quality Sr1-xKxFe2As2 tapes with processing at 800oC for 30 minutes and measured high Tc and sharp transition. This rapid fabrication method can effectively thwart the diffusion of Cu into polycrystalline Sr-122 core. As a consequence, we achieved high transport Jc of 3.1x10^4 A/cm^2 in 10 T and 2.7x10^4 A/cm^2 in 14 T at 4.2 K. The in-field Jc performance is by far the highest reported for Cu-sheathed high-Tc conductors. Our results demonstrate the potential of Cu sheath for practical application of pnictide wires and tapes.