Doping Effect on Partial-Melting of HgxBa2Ca2Cu3Re0.2Oy Filament
We have studied the fabrication of filamentary Fig system superconductor using a solution spinning method with Re addition. A controlled vapor/solid reaction process is necessary for preparing Hg-based superconductor by this method. As the F-doping resulted in a dense liquidus texture, F and Cl doping effects on partial-melting of filamentary Hg x Ba2Ca2Cu3Re0.2O y superconductor are examined to enhance the J c and to reduce the inciting temperature. A filamentary Ba2Ca2Cu3Re0.2O y precursor was spun by a solution spinning method and partially melted in an evacuated quartz tube with a pellet as a reactor. Hg1Ba1.8Ca2Cu3Re0.2(BaF2)0.2O y , Hg0.8Ba1.8Ca2Cu3Re0.2(BaF2)0.2O y , Hg1Ba2Ca2Cu2.8Re0.2(CuF2)0.2O y , Hg0.925Ba2Ca2Cu3Re0.2(HgCl2)0.075O y and Hg0.8Ba1.8Ca2Cu3Re0.2(BaF2)0.2(HgCl2)0.03O y pellets were prepared by a two-step solid state reaction method.
The partial-inelting temperature of the filamentary sample reacted with Hg1Ba2Ca2Cu2.8Re0.2(CuF2)0.2O y pellet was lower than others. The texture of the filamentary sample was dependent on the vaporizing materials. The J c of the sample was enhanced by post-annealing up to 350 °C in O2 flow. By controlling the heating condition, a high J c value more than 104 A/cm2 at 77 K and 0 T was attained for both F and Cl doped sample.
KeywordsVapor Source Doping Source Evacuate Quartz Tube Ammonium Perrhenate Detail Phase Diagram
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