Superconductivity of equilibrium solid solutions

Binary metallic systems whose alloys have no structural transformations and are close to ideal disordered solutions are considered. It is shown by analysis of experimental data that alloying in these systems is always accompanied by a decrease in superconductivity temperature and in the electronic heat capacity Sommerfeld coefficient. The concentration dependences of these parameters are qualitatively truly represented by chain lines and are brought into agreement with each other through the agency of an impurity contribution to the electron-phonon interaction coupling constant lambdasub(imp) infinitely x(1-x). This contribution is always negative and is the main cause of the lowering of superconductivity temperature by nonmagnetic impurities. One of the elementary dependences underlying the superconductivity diagram technique, the dependence of Tsub(c) versus x for the typically metallic state of solids, has been substantiated. (orig.)