Superconductivity and Electronic Specific Heat in the Scandium-Zirconium System

An investigation of the superconducting transition temperature and the electronic specific heat for the alloy system scandium-zirconium is reported. The results show that the alloys with the largest electronic specific heats are not superconducting down to 0.03°K. When compared with the other early transition metals (those with less than half-filled $d$ shells), the data for this system indicate a sharp decrease in the strength of the net attractive electron-electron interaction as one decreases the number of $d$ electrons (i.e. moves from zirconium to scandium). This behavior, combined with the apparently large exchange enhancement of the spin susceptibility in pure Sc, is very similar to the recently reported behavior near the filled end of the transition metals (i.e., near Pd). It is suggested that the proximity of a $d$-band edge may be causing the anomalous behavior in the superconductivity and the spin susceptibility for both regions of the transition metals.