Comparative study of the thermodynamics of superconducting Nb/sub 0.75/Zr/sub 0.25/ and Nb

From the mircoscopic parameters derived from tunneling for Nb/sub 0.75/Zr/sub 0.25/ and Nb we compute and compare their thermodynamic properties using the imaginary frequency axis formulation of Eliashberg theory. While these two materials have similar critical temperatures, Nb/sub 0.75/Zr/sub 0.25/ is found to show much larger strong coupling corrections than does Nb. The substantial increase in the gap to critical temperature ratio observed experimentally can easily be understood by functional derivative techniques