The Takahashi-Tachiki equations, describing the critical properties of proximity effect systems in the dirty limit, are solved exactly using the full eigenfunction expansion. Both parallel and perpendicular critical fields are calculated. The theory is applied to experimental data of Kanoda et al. for V/Ag and of Chun et al. for Nb/Cu, using the T_c of the superconducting material and the diffusion coefficients of both materials as fit parameters. For the 3D systems the fits compare nicely with the experimental results, but for 2D systems this is not always the case. It is found that the V and Nb critical temperatures necessary to fit the data can be larger than the corresponding bulk critical temperatures. This contrasts with what has been observed for single V and Nb films. Additionally, the diffusion coefficients resulting from the fit procedure are found to be much smaller than one would expect from resistivity measurements. In the light of these anomalies earlier less complete calculations are reconsidered. It turns out that several assertions are superficial and cannot be affirmed by the results of the present work.

Date Published: 29 June 1994
PDF: 11 pages
Proc. SPIE 2157, Superconducting Superlattices and Multilayers, (29 June 1994); doi: 10.1117/12.179177

Published in SPIE Proceedings Vol. 2157:
Superconducting Superlattices and Multilayers
Ivan Bozovic, Editor(s)