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 J _c 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 J _c 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.