Collective motion of Josephson vortices in Bi2Sr2CaCu2O8+delta mesa structures

Abstract

We studied the collective motion of Josephson vortices generated by microwave irradiation and by an external dc magnetic field applied in parallel with the planes of intrinsic junctions of Bi2Sr2CaCu2O8+delta single crystals. In both cases, for a low vortex density and driving current, splitting of the 'supercurrent' branch corresponding to different plasma excitation modes was observed in the current-voltage characteristics (IVC). For a high vortex density in fields beyond 3-4 T, the IVC merged into a single non-hysteretic curve with kinks, similar to those arising from the theoretically proposed structural transformation of moving vortex patterns. (C) 2003 Elsevier Science B.V. All rights reserved.