Fabrication and Characterizations of KCa2Fe4As4F2 Superconducting HIP Wires

We report the fabrication and characterizations of KCa2Fe4As4F2 round wires for the first time. Polycrystalline KCa2Fe4As4F2 powder was prepared by solid-state reaction. Superconducting wires were fabricated by powder-in-tube (PIT) method followed by hot-isostatic-press (HIP) technique. The self-field Jc of the KCa2Fe4As4F2 HIP wires fabricated at 700 and 740°C at a high pressure of 9 MPa for 0.5 h, reached 10 kAcm−2. Although high-pressure sintering at high temperatures enhanced the Jc and density of the core of the wires, X-ray diffraction and scanning electron microscopy–energy-dispersive X-ray spectroscopy analyses indicated that impurity phases were present both in the polycrystalline powder and in the core of the wire.