Enhancement of critical current densities in (Ba,K)Fe₂As₂ by 320 MeV Au irradiation in single crystals and by high-pressure sintering in powder-in-tube wires

We demonstrate a large enhancement of critical current density (J_c) up to 1.0×10⁷ A/cm² at 5 K under self-field in (Ba,K)Fe₂As₂ single crystals by irradiating 320 MeV Au ions. With the very promising potential of this material in mind, we have fabricated a (Ba,K)Fe₂As₂ superconducting wire through a powder-in-tube method combined with the hot isostatic pressing technique, whose effectiveness has been proven in industrial Bi2223 tapes. The J_c in the wire at 4.2 K has reached 37 kA/cm² under self-field and 3.0 kA/cm² at 90 kOe. Magneto-optical imaging of the wire confirmed the large intergranular J_c in the wire core. (author)