Superconductivity in amorphous thin films of tin-copper

The properties of the superconducting state in the amorphous Sn1-xCux thin films were characterized. The concentration of copper changes in the range from 0.08 to 0.41. The calculations were conducted in the framework of the strong-coupling formalism, wherein the Eliashberg functions determined in the tunnel experiment were used. The value of the Coulomb pseudopotential equal to 0.1 was adopted. It will be shown that the critical temperature (T-C) decreases from 7 to 3.9 K. The ratio, R = 2(0)/k(B)T(C), differs from the BCS value: R <4.4, 3.95>, where (0) represents the order parameter. Similarly behave the ratios: R-C = C(T-C)/C-N(T-C) <2.2, 1.75> and R-H = TCCN(T-C)/H-C(2)(0) <0.141, 0.154>. The parameter C(T-C) is the specific heat jump, C-N(T-C) denotes the specific heat of the normal state and H-C(0) is the thermodynamic critical field.