  (Ba,K)Fe2As2 superconducting wires and tapes are fabricated by using hot
isostatic pressing (HIP) technique, and their superconducting properties are
studied. In the HIP round wire, transport critical current density (Jc) at 4.2
K has achieved record-high value of 175 kA/cm2 at zero field, and exceeds 20
kA/cm2 even at 100 kOe. Improvement of polycrystalline powder synthesis may
play a key role for the enhancement of Jc. In the HIP tape, even larger
transport Jc of 380 kA/cm2 is realized at zero field. Based on magnetization
and magneto-optical measurements, possible further enhancement of Jc is
discussed.
