Critical current density for filamentary (Nd, Eu, Gd)Ba₂Cu ₃O_y superconductors

In order to study the effect of matrix composition in the filamentary (Nd, Eu, Gd)Ba₂Cu₃O_y ((Nd, Eu, Gd)123) superconductors on critical current density, we prepared three samples with various rare-earth ratios: (Nd_0.33Eu_0.38Gd _0.28)123 (sample A), (Nd_0.33Eu_0.33Gd _0.33)123 (sample B), (Nd_0.33Eu_0.08Gd _0.58)123 (sample C). The filamentary precursor was prepared by a solution-spinning method and partially melted in flowing 0.1%O₂+Ar and 1%O₂+Ar. The samples had well aligned texture along the filamentary diameter as well as the length except sample C processed in flowing 1%O₂+Ar. The T_c value for the samples processed in flowing 0.1%O₂+Ar is higher than that for 1%O₂+Ar. The high J_c value more than 10⁴ A/cm² at 77 K and self-field is attained for samples A and B. The field dependence of J _c for the samples was measured at 77 K up to 14 T by changing the angle along the filament diameter. The anisotropic behavior of the J _c-B curve was detected. The J_c values and irreversibility field for the samples processed in flowing 0.1%O₂+Ar are higher than those for 1%O₂+Ar. By optimizing the angle for the samples, the highest J_c value of 3400 A/cm² at 14 T was attained for sample A.