Electronic density of states in amorphous zirconium alloys

We have produced amorphous Zr-Rh, Zr-Ru, and Zr-Re films by means of rf diode cosputtering techniques. Measurements were made of the superconducting transition temperature T/sub c/, the normal resistivity rho, and upper critical field H/sub c/2. From rho and (dH/sub c/2/dT)c we determined the dressed density of states at the Fermi level N* = N(1+lambda), where lambda is the electron-phonon coupling constant and N is the bare density of states. For Zr-Rh and Zr-Re, N* exhibited an approximately linear decrease as the Zr fraction decreased. For Zr-Ru alloys the behavior was more complex. Estimating N for Zr-Rh alloys, we find it to be approximately the same in magnitude and composition dependence as the N for Zr-Cu alloys. We calculate the magnitude and composition dependence of N for Zr-Rh and Zr-Cu alloys with the use of a simple model and obtain good agreement with the experimental results