Abstract: We measured the current-induced loss of vortex correlation in YBa2Cu3O7-δ crystals using the pseudo-dc-flux-transformer geometry. We find that the current density Jcut at which the top and bottom voltage drops differ is a linear function of temperature, is independent of pinning, and depends on the thickness of the sample. This thickness dependence strongly suggests that the electrical current flows at the surface of the sample. The observed behavior with temperature, magnetic field, and thickness is described by a phenomenological model.