Enhanced flux pinning by phase decomposition in Y-Ba-Cu-O

Significantly improved flux pinning has been achieved in bulk YBa2Cu3O7−δ superconductor (‘‘123’’ compound) containing fine-scale defects (<∼50 Å thick). The measured Jc intragrain of ∼105 A/cm2 at 77 K, H=0.9 T is about ten times higher than the typical values for bulk Y-Ba-Cu-O. The improved structure was produced by rapid decomposition at 920 °C of the YBa2Cu4O8 (‘‘124’’) precursor. This new and simple processing route could lead to a commercially viable processing technique for flux-pinning enhancement in bulk Y-Ba-Cu-O.