SUPERCONDUCTING PROXIMITY EFFECT IN CU CLAD NB WIRES DOPED WITH MN, FE, CO AND NI

The proximity effect in Cu clad Nb wires of which Cu is doped with dilute magnetic impurities, has first been investigated in relation to the Kondo effect. As for Cu doped with dilute Fe, Co and Ni impurities, the probability of the spin flip scattering of conduction electrons, alpha, by Fe, Co and Ni impurities decreases linearly with decreasing temperature. As for Cu doped with dilute Mn impurities, the probability, alpha, by Mn impurities is concluded to be suppressed by the RKKY interaction between Mn impurities which depends on the electronic mean free path. The temperature dependence of the resistivity of the Mn alloy may be understood as a result of the coexistence of the dilute Kondo effect and the RKKY interaction between Mn impurities.