Planar Josephson tunnel junctions in an asymmetric magnetic field

Abstract

We analyze the consequences resulting from the asymmetric boundary conditions imposed by a nonuniform external magnetic field at the extremities of a planar Josephson tunnel junction and predict a number of testable signatures. When the junction length L is smaller than its Josephson penetration depth λj, static analytical calculations lead to a Fresnel-like magnetic diffraction pattern, rather than a Fraunhofer-like one typical of a uniform field. Numerical simulations allow to investigate intermediate length (L≈λj) and long (L>λj) junctions. We consider both uniform and δ-shaped bias distributions. We also speculate on the possibility of exploiting the unique static properties of this system for basic experiments and devices.