Intrinsic superconductor/normal-metal/superconductor-like weak links in Y1Ba2Cu3O7−x thin films

Magnetotransport measurements on micron-sized wires of the thin-film high Tc superconductor Y1 Ba2 Cu3 O7−x made by pulsed laser deposition reveal an exponential suppression of the critical current with magnetic field, and a power law dependence of the critical current on reduced temperature. We ascribe this behavior to crystallographic defects in the film which behave as superconductor/normal-metal/superconductor weak links in a magnetic field. From the measurements we estimate a critical current density of 106 A cm−2 in a field of 16 T at 4.2 K.