Superconductivity, Susceptibility, and Specific Heat in the Noble Transition Elements and Alloys. I. Experimental Results

We present experimental results of a study of superconductivity and magnetic susceptibility in face-centered-cubic alloys of Ir with Ru, Rh, Pd, Re, Os, and Pt, mostly on the Ir-rich side. The results show that the filling up of the d band first depresses the superconducting transition temperature and then causes the susceptibility to increase rapidly. There is a correlation between these two experimental parameters in that metals with large (exchange enhanced) susceptibilities are not superconducting above our experimental limit (0.015^∘{}K). We predict that Pd will not superconduct even at 0^∘{}K and that superconductivity in Rh and Pt will occur far below 10^-3 ^∘{}K, if at all.