Critical current and fluxon dynamics in overdamped 0-π Josephson junctions

A one-dimensional overdamped 0-π Josephson junction, is studied numerically. The magnetic-field-dependent critical current patterns for short and long 0-π junctions differ greatly, due to the spontaneous complete formation of a semifluxon in the latter. In both cases, however, they do not resemble the corresponding patterns for conventional (0) junctions. The current-voltage characteristics for long 0-π junctions, also differ considerably from those of 0-junctions for low bias current. For sufficiently large damping it seems that a new dynamic mode appears, in which the semifluxon oscillates while emitting integer fluxons and antifluxons, one in each oscillation period, which anihilate when they reach the ends of the junction. This effect, which appears for a rather large bias current range, seems to be absent in the underdamped case.