Effect of localized spin fluctuations on superconducting properties of dilute alloys

Abstract

The effects of localized spin fluctuations on the critical temperature Tc and the specific-heat jump Δ C (Tc) of dilute superconducting alloys is investigated, both in the weak and strong magnetic limits. In the weak magnetic limit (rapid spin fluctuations) we find that the expression of Kaiser for Tc(nI), where nI is the impurity concentration, which was derived for resonance scattering still holds with redefined values of the pertinent parameters, while the specific-heat jump obeys a BCS law of corresponding states. In the slow-spin-fluctuation limit the result of Abrikosov and Gor'kov (AG) for Tc(nI) is recovered, with a redefined expression for the Cooper-pair lifetime, while Δ C (Tc) as function of reduced temperature is depressed below the AG value