High critical current density in Cu/Ag composited sheathed Ba_0.6K_0.4Fe₂As₂ tapes prepared via hot isostatic pressing

Abstract

Iron-based superconductors (IBSs) with ultrahigh upper critical fields and low anisotropies have attracted significant attention in terms of the novel mechanism of superconductivity and high-field applications. A major concern for practical research is the fabrication of long wires with enhanced critical current density and low cost. In this paper, Cu/Ag composited sheathed Ba0.6K0.4Fe2As2 (Ba122) tapes were fabricated through a hot isostatic pressing method, which is feasible for long-wire manufacturing. The Cu/Ag composite sheath can lower the tape cost by reducing the use of expensive Ag. A high-transport critical current density (Jc) up to 5.8 × 104 A cm−2 under 10 T at 4.2 K was achieved in our tapes. Evidence has shown that these tapes have pure Ba122 phase, homogeneous element distribution, orientated grains and good grain connectivity. Our work shows that low-cost Cu/Ag-sheathed IBS tapes have great promise for practical applications in the future.