SIZE-EFFECT OF KONDO SCATTERING IN POINT CONTACTS (REVISITED)

The size-effect of Kondo-scattering in nanometer-sized metallic point contacts is measured with the simplified, mechanically-controlled brea k-junction technique for CuMn alloy of different Mn concentrations: 0. 017; 0.035; and 0.18 (+/-0.017) at.%. The results are compared with ou r previous publication on nominally 0.1 at. % CuMn alloy.(1,2) The inc rease of width of the Kondo resonance and enhanced ratio of Kondo-peak intensity to electron-phonon scattering intensity is observed for con tacts with sizes smaller than 10 nm. From the comparison of electron-p honon scattering intensity for the pressure-type contacts, which corre spond to the clean orifice model, we conclude that the size effect is observed in clean contacts with the shape of a channel (nanowire). (C) 1998 American Institute of Physics. [S1063-777X(98)00807-X].