Interpretation of a microwave induced current step in a single intrinsic Josephson junction on a Bi - 2223 thin film

Thin stacks consisting of a single intrinsic Josephson junction on (Bi,Pb)-Sr-Ca-Cu-O thin films are investigated under the influence of external microwave fields. The I-V-characteristic shows a single resistive branch, a clear superconducting gap edge structure and a pronounced current step in external microwave fields. With increasing irradiation power it shifts to higher voltages, while the height of the step remains practically unchanged. In a numerical simulation including an ac-magnetic field parallel to the superconducting layers the experimental features of the structure can be explained by a collective motion of Josephson fluxons.