Observation of coherent modes of Josephson vortices in Bi2Sr2CaCu2Ox

Abstract

We report strong evidence for coherent modes of moving Josephson vortices in mesas patterned on the surface of Bi2Sr2CaCu2Ox single crystals. The vortex flow current–voltage curves are characterized by a sharp up-turn and the appearance of multiple branches as the current is ramped up and down at a fixed magnetic field and temperature. These results are consistent with weakly damped motion of Josephson vortices in which different coherent modes can occur in a close stack of Josephson coupled multilayers.