THE ABRIKOSOV VORTICES EFFECT ON CRITICAL CURRENT OF THE JOSEPHSON TUNNEL JUNCTION

The theoretical analysis of the critical current (I(c)) of the Josephson tunnel junction (JTJ) versus the concentration of trapped Abrikosov vortices (AV) of the different types is carried out. In the experiment there are two methods for trapping of AV into the niobium films based JTJ, such as, cooling the JTJ in magnetic field applied perpendicular to the plane of the tunnel junction (H perpendicular-to) through critical temperature (T(c)) and applying the field H perpendicular-to when the JTJ is at T < T(c). It is shown that the maximum critical current (I(c)max) falls exponentially with increasing of H perpendicular-to under trapping of misaligned primary-secondary vortices and the characteristic point of inflection is observed in the behavior of I(c)max(H perpendicular-to) dependence for primary-only vortices. The experimental I(c)max(H perpendicular-to) curves allow to determine the average degree of the misalignment of vortices and to perform also the numerical estimation of critical current density of superconducting niobium film. The dependences of I(c) on magnetic fueld applied parallel to the plane of the tunnel junction are discussed for various types of trapped AV.