Josephson effect in SIFS-tunnel junctions with domain walls in weak link region

摘要

We study theoretically the properties of SIFS type Josephson junctionscomposed of two superconducting (S) electrodes separated by an insulating layer(I) and a ferromagnetic (F) film consisting of periodic magnetic domainsstructure with antiparallel magnetization directions in neighboring domains.The two-dimensional problem in the weak link area is solved analytically in theframework of the linearized quasiclassical Usadel equations. Based on thissolution, the spatial distributions of the critical current density, $J_{C},$in the domains and critical current, $I_{C},$ of SIFS structures are calculatedas a function of domain wall parameters, as well as the thickness, $d_{F},$ andthe width, $W,$ of the domains. We demonstrate that $I_{C}(d_{F},W)$dependencies exhibit damped oscillations with the ratio of the decay length,$\xi_{1},$ and oscillation period, $\xi_{2},$ being a function of theparameters of the domains, and this ratio may take any value from zero tounity. Thus, we propose a new physical mechanism that may explain the essentialdifference between $\xi_{1}$ and $\xi_{2}$ observed experimentally in varioustypes of SFS Josephson junctions.