Controllable Reduction of J sub c in YBa sub 2 Cu sub 3 O sub 7-variation Films by Ion Irradiation

Most technological applications for the high Tc sub 2 superconductors require critical current densities in excess of 10 sup 5 A/cm sup 2 at 77K. However, for applications which involve the Josephson effect and require a "weak link" between two regions of good superconductor, the ability to controllably reduce the critical current in a selected area would be very convenient.