Properties of Hg-1223 Superconducting Thin Films Prepared by Pulsed Laser Deposition

We have recently succeeded in fabricating both Re-free and Re-doped c-axis Hg-1223 superconducting thin films on SrTiO3 (100) substrates using the two-step process which consists of the preparation of amorphous precursor films by pulsed laser deposition and subsequent annealing in mercury-vapor atmosphere. Almost phase-pure Re-doped Hg-1223 films are obtained using HgO/Re0.1Ba2Ca2Cu3O y multi layer precursor films with an HgO protective layer. Re-doped Hg-1223 films exhibit a T c (zero) of 127.5 K which is slightly higher than that of Re-free Hg-1223 films. They also show a transport Jc at 77 K of 1.5 × 106 A/cm2 in a self-field and 1.2 × 105 A/cm2 under magnetic field of 1 T. The effects of Re doping on the structural and superconducting properties are confirmed. Moreover, we have fabricated artificial grain boundary junctions using Re-doped Hg-1212 thin films on SrTiO3 bicrystal substrates and observed a weak-link behavior at temperatures below 119 K, which is close to the film T c of 122 K.