Critical current density of both F and Cl doped filamentary Hg1223 superconductors

The effect of both F and Cl doping on a transport critical current density (J(c)) of the filamentary Hg1223 superconductors was examined to enhance a reproducibility of high J(c). A filamentary precursor Ba2Ca2Cu3Re0.2Ox was fabricated using a solution spinning method and partially melted in an evac uated quartz tube with a pellet of Hg0.8Ba1.8Ca2Cu3Re0.2(BaF2)(0.2)(CuCl)(0 .03)O-x. The addition of BaF2 and CuCl as a doping vapor source enhanced th e reproducibility and stability of the high je value at 77 K and 0 T for th e filamentary sample owing to the homogeneous fine grain texture. Field dep endence of the J(c) for the filamentary sample was strongly dependent on th e post-annealing condition. Although the J(c) value for the as-reacted samp le and the sample post-annealed in flowing O-2 decreased rapidly by applyin g the field less than 0.5 T, high J(c) value exceeding 10(3)A/cm(2) was mai ntained at 77 K in a field of 10 T by post-annealing in flowing Ar.