Development of Powder-in-Tube Processed Iron Pnictide Wires and Tapes

TL;DR

This paper reports the successful development of powder-in-tube processed iron pnictide superconducting wires and tapes with improved transport properties, achieving record critical current densities and demonstrating feasible low-temperature fabrication.

Contribution

It introduces optimized PIT fabrication techniques for iron pnictide wires and tapes, including the use of silver sheaths and doping, leading to enhanced performance and lower processing temperatures.

Findings

Critical current density exceeds 3750 A/cm^2 at 4.2 K.

Silver sheath prevents reaction layers, improving grain connectivity.

Superconducting tapes fabricated at 900°C show promising results.

Abstract

The development of the PIT fabrication process of iron pnictide superconducting wires and tapes has been carried out in order to enhance their transport properties. Silver was found to be the best sheath material, since no reaction layer was observed between the silver sheath and the superconducting core. The grain connectivity of iron pnictide wires and tapes has been markedly improved by employing Ag or Pb as dopants. At present, critical current densities in excess of 3750 A/cm^2 (Ic = 37.5 A) at 4.2 K have been achieved on Ag-sheathed SrKFeAs wires prepared with the above techniques, which is the highest in iron-based wires and tapes so far. Moreover, Ag-sheathed Sm-1111 superconducting tapes were successfully prepared by PIT method at temperatures as low as 900C, instead of commonly used temperatures of 1200C. These results demonstrate the feasibility of producing superconducting pnictide composite wires, even grain boundary properties require much more attention.