Critical current properties in superconducting Y-123 tapes

The critical current density and the irreversibility field were measured for a coated Y-123 tape prepared by IBAD method. These results were compared with those of Y-123 thin film deposited on single crystal STO. It was found that J(c) of the tape has a weaker magnetic field dependence, although its value at low fields is fairly lower than that of the thin film. This comes from the difference of the thickness. The lower J(c) at low fields is due to the collective pinning property, and the better irreversibility at high fields can be attributed to a larger flux bundle volume. These results were compared with the calculated results using the flux creep-flow theory, and a good agreement was obtained. J(c) was estimated with the aid of this theory assuming that a high-quality thick tape of 5 mum thick with strong pinning can be fabricated. (C) 2002 Elsevier Science B.V. All rights reserved.