Melt processing of La-Ba-Cu-O superconductors with high Tc

We have successfully melt-processed La-Ba-Cu-O bulk superconductors which exhibit high Tc and large Jc values. The employment of a 0.1% O2-Ar atmosphere and a Ba-rich La4-xBa2+xCu2-xO10-2x second phase as a precursor was the key to obtaining a high Tc phase. Fabricated bulk samples exhibit onset Tc of 94 K and the secondary peak effect in the Jc -B curve. The respective peak position and the irreversibility field were 1 T and 4.5 T at 77 K and the Jc at the peak field was about 18000 A cm−2.