Field dependence of J_c for filamentary RE-Ba-Cu-O superconductors prepared by a solution spinning method

The filamentary RE-Ba-Cu-O (RE = Nd, Nd-Eu-Gd, and Nd-Sm-Eu-Gd) precursor was prepared by a solution spinning method, through a homogeneous aqueous solution containing mixed acetates of RE, Ba and Cu, poly(vinyl alcohol) and organic acids. The filamentary precursor was partially melted in flowing 0.1%O₂+Ar or 1%O₂+Ar and then oxygenated under various conditions. The transport critical current density (J_c) of the samples was measured in magnetic fields up to 10 T at 77 K. The influence of field dependence of J_c on the initial different RE elements in the filamentary RE-Ba-Cu-O superconductors was examined. The field dependence of J_c was improved by mixing three or four different RE elements. The J_c value at 77 K and up to 6 T for the sample partially melted in flowing 0.1%0₂+Ar was higher than that for the sample melted in flowing 1%O₂+Ar. The highest J_c value of more than 1.76 ×10⁴ A/cm² at 77 K and 9 T was detected for filamentary Nd-Sm-Eu-Gd-Ba-Cu-O superconductors partially melted in flowing 0.1%O₂+Ar.