Transition temperature of proximity-effect sandwich systems containing Kondo impurities

Abstract

The superconducting proximity effect between thin films of a superconductor and a Kondo alloy is analyzed, using the McMillan tunneling model and the theory of Matsuura, Ichinose, and Nagaoka (MIN). The transition temperature is derived and shown to recover the already known limiting cases: the BCS, McMillan, Mohabir-Nagi, Kaiser, and MIN results. An expression for the effective pair-breaking parameter, different from that of Müller-Hartmann and Zittartz, is obtained and found to contain the terms arising from the impurity effect and the pair-weakening Coulomb repulsion effect. © 1982 Plenum Publishing Corporation.