The Superconducting Proximity Effect as a Tool to Investigate Metal Films and Interfaces

TL;DR

This paper investigates the superconducting proximity effect in Pb and alkali metal sandwiches to analyze interface barriers, revealing significant barriers in Pb/Cs interfaces and applying a modified Cooper limit for transition temperature calculations.

Contribution

It introduces a method to study interface barriers using the proximity effect and applies a modified Cooper limit to interpret the data.

Findings

Large interface barrier in Pb/Cs sandwiches.

Barrier not caused by impurities or oxidation.

Modified Cooper limit successfully describes transition temperatures.

Abstract

052<p type="texpara" tag="Body Text" et="abstract" >The superconducting proximity effect is measured in sandwiches of thin Pb films and the alkali metals Cs, Rb, K and Na. The $T_{c}$-dependence provides information about the interface barriers between Pb and the alkalis. Such a barrier is particularly large in Pb/Cs sandwiches. It is not due to impurities or oxydation. In the presence of a sufficiently strong barrier a special form of the Cooper limit can be applied to calculate the transition temperature of the sandwich.