Magnetic impurities in superconductors

Abstract

This paper reviews the recent experimental and theoretical works on the effect of magnetic impurities in superconductors, with special emphasis on the effect of anomalous exchange scattering. Experimental evidence is presented which shows that the effect of the anomalous exchange scattering has a considerable contribution to the thermodynamic properties and the electron tunneling. The effect is larger for the impurities which interact with conduction electrons antiferro-magnetically than the impurities which interact ferromagnetically. The existence of the bound state, predicted by a number of theories, seems difficult to confirm experimentally, although the anomalies found in electron tunneling into some dilute magnetic alloys seem to bear on it. The effect of the anomalous exchange scattering on the proximity effect is also discussed.