Characterization of pinning and vortex motion in thin superconducting microbridges

We show that transport measurements carried out with and without a low applied magnetic field enable one to characterize the vortex dynamics in high-T-c superconducting films. The application of a low magnetic field induces a modulation of the critical current that depends on the process involved when the vortices are set in motion. Current-voltage measurements with no applied field yield information on the pinning energy, the pinning sites density, and the way the vortices are moving. Measurements carried out on a set of YBa2Cu3O7 microbridges show that the vortex dynamics depend primarily on the pinning sites density. This quantity proves to be strongly dependent on the thickness of the superconducting film.