FRACTIONAL FLUX EXCITATIONS AND FLUX-CREEP IN A SUPERCONDUCTING FILM

We consider the transport properties of a modulated superconducting fi lm in a magnetic field parallel to the film. Modulation can be either intrinsic, due to the layered structure of the high-T-c superconductor s, or artificial, e.g. due to thickness modulation. This system has an infinite set (<<devil staircase>>) of pinned phases. In the pinned ph ase the excitation of flux loops with a fractional number of flux quan ta by the applied current j results in flux creep with a generated vol tage V proportional to exp[-j(0)/j].