We have succeeded in fabricating Nd-Ba-Cu-O bulk superconductors, which exhibit high Tc and a sharp superconducting transition, by the melt process in air without additional high temperature annealing in a reduced oxygen atmosphere. The key to this achievement is the use of Ba-rich Nd4-2zBa2+2zCu2-zO10-δ as a precursor. Fabricated bulk samples exhibit onset Tc values of 94-95 K and the secondary peak effect in the M-H loop like the case of Nd-Ba-Cu-O superconductors produced by melt processing in a reduced oxygen atmosphere. The peak position and the irreversibility field for the best sample were about 1.2 T and 5 T at 77.3 K, respectively, and the estimated Jc at the peak field was about 2.3 × 104 A cm-2.
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