Proximity effect in superconductors: Experimental and theoretical determination of the transition temperature

This thesis is a report of the results of experimental and theoretical investigations of the proximity effect in superconductors, with particular reference to the measurement and prediction of the transition temperature of superimposed films. The theoretical work consists of two parts: (1) an extension of the diffusion approximation theory due to de Gennes, Guyon and Werthamer; this theory is valid only when the mean free paths in the two metals are small compared to the respective coherence lengths, (ii) an extension, under certain restrictive assumptions, of the above theory to all values of the mean free paths. The experimental work consists of measurements of the transition temperature of superimposed films of indium and thallium deposited at low temperatures. The experimental results are in good over-all agreement with the theory but small deviations are observed. Similar but far less extensive measurements have also been made for lead-indium films, for which the strong electron-phonon coupling in lead might invalidate the theory. The experimental results are again in good agreement with the theory, showing that the strong-coupling effects are not large.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Jacobs, Allan Edward

Contributors dc:contributor

• Ginsberg, D.M.

• proximity effects
• superconductors
• transition temperature
• superimposed film

Statement dc:rights

• 1968 Allan Edward Jacobs

Language dc:language

en

Identifier

6079084

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25750