Vortex confinement in oxygen-deficient Y-Ba-Cu-O films

The aim of this work is to investigate the mechanisms controlling the current-carrying capability of YBa(2)Cu(3)O(7-delta) thin films. A comparison between the magnetic properties of as-grown films and films crossed by columnar defects, produced through 0.25 GeV gold-ion irradiation, is shown. The central issue concerns the investigation of the plateau-like features characterizing the log-log field dependence of the critical current density and the analysis of the irreversibility line. Data and models suggest that the intergrain pinning of the flux vortices channelling along a network of Josephson junctions dominates in the high-current low-temperature regime, while the intragrain pinning is effective near the irreversibility line.