Fabrication of (Ba,Na)Fe₂As₂ round wires using HIP process

We have fabricated round wires of Baa_0.6Na_0.4Fe₂As₂ using powder-in-tube technique and hot isostatic press (HIP) treatment. Transport J _c was measured at 4.2 K of two Ba_0.6Na_0.4Fe₂As₂ round wires with Ag/Cu double sheath which were processed at 700 °C for 4 h at 175 MPa. Transport J _c of one of the wires reached 76 kA/cm² and 24 kA/cm² at self-field and 100 kOe, respectively, while J _c of another wire is slightly larger at low fields. It means that J _c of Ba_0.6Na_0.4Fe₂As₂ wire is resilient against large magnetic field, which demonstrates very promising characteristics of this material. Detailed characterizations of wires using X-ray diffraction and compositional mapping by EDX are also presented. We also explore the better condition for synthesis of Ba_0.6Na_0.4Fe₂As₂ by changing the reaction temperature. (paper)