The influence of the boundary resistivity on the proximity effect

We apply the theory of Takahashi and Tachiki in order to explain theoretically the dependence of the upper critical magnetic field of a S/N multilayer on the temperature. This problem has been already investigated in the literature, but with a use of an unphysical scaling parameter for the coherence length. We show explicitely that, in order to describe the data, such an unphysical parameter is unnecessary if one takes into account the boundary resisitivity of the S/N interface. We obtain a very good agreement with the experiments for the multilayer systems Nb/Cu and V/Ag, with various layer thicknesses.Comment: 12 pages, 5 figure

Calcualtion of the upper critical fields in Nb/Ta multilayers.

The Takahashi-Tachiki proximity-effect theory is applied to the Nb/Ta multilayer system. The diffusion coefficients of the two metals and the critical temperature of Nb are used as free parameters in fitting experimental phase diagrams. Magnetic-coherence-length scaling is used in order to obtain phase diagrams that best reproduce the measured data. Several parameter sets can compete in fitting an experimental curve. It is not always possible to decide which set gives the most realistic result