Josephson current in superconductors with nonmagnetic impurities

Boundary conditions to the Ginsburg–Landau equations are found for the problem of the Josephson tunnel contact in the presence of small concentration of nonmagnetic admixture in the superconductors. It is shown that in the case of small trasparency, the change of the coefficient in the boundary condition due to the admixtures compensates exactly the corresponding change of the coefficient in the expression of the current. As a result, the effect of the admixtures vanishes. If the transparency is not small, the admixtures change the value of the Josephson current; in particular, in the limit of large admixtures decreasing of the value of the current is determined by factor $l/\xi_0$.