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

The effect of both F and Cl doping on the transport critical current density (J/sub c/) of the filamentary Hg1223 superconductors was examined to enhance the reproducibility of high J/sub c/. A filamentary precursor Ba/sub 2/Ca/sub 2/Cu/sub 3/Re/sub 0.2/O/sub x/ was fabricated using a solution spinning method and partially melted in an evacuated quartz tube with a pellet of Hg/sub 0.8/Ba/sub 1.8/Ca/sub 2/Cu/sub 3/Re/sub 0.2/(BaF/sub 2/)/sub 0.2/(CuCl)/sub 0.03/. The addition of BaF/sub 2/ and CuCl as a doping vapor source enhanced the reproducibility and stability of the high J/sub c/ value at 77 K and 0 T for the filamentary sample owing to the homogeneous fine grain texture. Field dependence of the J/sub c/ for the filamentary sample was strongly dependent on the post-annealing condition. Although the J/sub c/ value for the as-reacted sample and the sample post-annealed in flowing O/sub 2/ decreased rapidly by applying the field less than 0.5 T, high J/sub c/ value exceeding 10/sup 3/ A/cm/sup 2/ was maintained at 77 K in a field of 10 T by post-annealing in flowing Ar.