Precursor filaments with starting composition (Nd0.33,Sm 0.33,Gd0.33) : Ba : Cu = 1.18 : 2.12 : 3.09 were prepared by a solution spinning method. Samples were partially melted at temperature range of 1020-1090° C in flowing 0.1%O2 + Ar, 1%O2 + Ar and 20%O2 + Ar and then oxygenated in pure 100%O2 gas. The Tc value decreased from 91.3 K to 88.8 K with increasing oxygen concentration in atmosphere gas. A transport Jc value higher than 104 A/cm3 at 77 K and 0 T was showed over a wide temperature range of 1030-1080°C in 0.1%O2 + Ar and 1040-1090°C in 1%O2 + Ar. Especially, the 0.1%O2 + Ar sample partially melted at 1050°C and the 1%O2 + Ar sample at 1060° C exhibited the highest Jc value of 2.7 × 10 4 A/cm2 and 2.5 × 104 A/cm2, respectively. The transport Jc value of the sample melted in flowing 0.1%O3 + Ar was maintained higher than 2.4 × 103 A/cm3 at 77 K in applied magnetic fields up to 17 T. On the other hand, the maximum Jc value at 77 K and 0 T for the sample treated in 20%O2 + Ar melted at 1080°C showed 5.4 × 103 A/cm2 at most, and the superconductivity was disappeared at magnetic field of 7 T.
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