Fabrication and Transport Properties of 100 m Class Sr0.6K0.4Fe2As2 Wires and Pancake Coils

TL;DR

This paper reports the successful fabrication of 100-meter class Sr0.6K0.4Fe2As2 superconducting tapes and coils, demonstrating high current density, uniformity, and potential for practical superconducting device applications.

Contribution

First report of 100-meter class Sr122 tapes using powder-in-tube technique with high uniformity and performance, and fabrication of superconducting coils from these tapes.

Findings

Achieved an average Jc of 1.3x10^4 A/cm^2 at 10 T over 115 meters

Successfully fabricated coils with transport Ic from 7-filamentary tapes

Identified factors affecting superconducting properties of coils

Abstract

Iron-pnictides are hotly studied since 2008 in the superconducting materials research area, due to their special properties and unclear mechanism. Big achievement has been made in the pnictide research during the past years. For practical uses, pnictide superconductor should be fabricated in a long wire form which can be used for different devices. In this work, 100 m class 7-core Sr0.6K0.4Fe2As2 (Sr122) tapes have been made using the powder-in-tube technique, which is reported for the first time. Clearly, an average Jc of 1.3x10^4 A/cm^2 at 10 T was reached over the 115 meter length, showing a high property and good uniformity of 100 meter level Sr122 tapes. Using the 10 m long Sr122 tapes, two double-pancake coils were fabricated by a wind and reaction technique. No transport current could be measured for the coil made from the mono-filamentary tape. However, transport Ic was obtained in the coil made from the 7-filamentary tape. The factors which affect the superconducting property of the coil were discussed in this work.