Critical current of a long Josephson junction in the presence of a perturbing Abrikosov vortex

Abstract

We investigate theoretically how the proximity of an Abrikosov vortex influences the physical properties of a long Josephson junction. We find that dI c , the contribution to the critical current associated with the presence of the vortex, is generally positive ~the critical current is increased ! and is crucially dependent on the specific boundary conditions satisfied by the transport current. In the case in which the latter has a bulk component in the vicinity of the vortex, dI c is proportional to the coupling c between the vortex and the junction. The situation is however more complex when the transport current is purely a surface phenomenon. In this case dI c strongly depends on the distance between the vortex and the edges of the junction, and is in general much smaller than that of the bulk current case unless a special commensurability condition is met. In particular we show that a contribution to dI c proportional to c is obtained in this case only when an integer number of Josephson vortices can be accommodated between the location of the vortex and one of the edges of the junction. @S0163-1829~98!10137-6#