Fabrication and Superconductivity of Ba0.6K0.4Fe2As2/Ag Wires and Tapes Using Mechanical Alloyed Precursor

Abstract

Conventional methods of Ba 0.6 K 0.4 Fe 2 As 2 precursor preparation are complicated and expensive. In this paper, we describe the mechanical alloying of precursor by high-energy ball milling and its processing to wires and tapes. Our approach is to high-energy ball-mill a starting mixture of Ba and K pieces with Fe and As powders. The resultant powders are packed into an Ag sheath and reduced by groove rolling or flat rolling. Critical current density measurements were performed on unsintered wire and tape, and compared to the results of measurements on wire and tape sintered at 750 °C for 12 h. We achieved 6.98 × 10 4 A/cm 2 at 4.2 K and self-field in the sintered tape. Our results indicate that the mechanical alloyed precursor and the resulting Ag-sheathed Ba 0.6 K 0.4 Fe 2 As 2 wires and tapes are promising but require further development.