Superconductivity of alloy films of Mo and simple metal elements

Alloy films of Mo and simple metal elements M(M = Ag, Mg, Sn, Sb, Bi, and Ge) have been produced by coevaporation method on substrates kept at about 80 K and their structure and electrical resistivity have been measured. The Mo-Sn and Mo-Sb films are found to be amorphous superconductors with a superconducting transition temperature of about 6 K at most. The Mo-Bi films are also superconductors but crystalline; they show the same x-ray diffraction pattern as that of hcp Bi. The upper critical field H/sub c/2 has been measured for Mo-Sn and Mo-Sb films. The H/sub c/2 increases linearly with decreasing temperature down to 1.5 K. The value of H/sub c/2 extrapolated to 0 K is found to exceed the paramagnetic limit