Electron thermal conductivity of thin films of strong-coupling superconductors and of superconductors containing rare earth impurities

We have measured the thermal conductivity of several superconducting films. These films were evaporated onto substrates held at liquid helium temperatures, and therefore the phonon mean free path in these films was very short. Consequently, the phonons contributed very little to the thermal conductivity. The experimentally determined thermal conductivity was therefore due almost entirely to the conduction of heat by the electrons. The electron thermal conductivity Ke s of a strong-coupling superconductor and of superconductors containing rare earth impurities has been measured in this way. We have generalized the theoretical expression for Ke s of strong-coupling superconductors to include elastic scattering of the electrons. When elastic scattering of the electrons dominates,the expression for K es reduced to that of. Bardeen, Rickayzen, and Tewordt, except for a change in the energy gap width, These results are in good agreement with our experimental measurements on a quench-condensed film of lead. We have also measured the thermal conductivity of thin films of lead or indium containing small amounts of gadolinium, These results are in good agreement with theoretical results of Ambegaokar and Griffin (modified for strong-coupling effects), except at very low temperatures. We believe that the low temperature deviations are related to the properties of the substrate, rather than to the characteristics of the superconducting films.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2012

Author dc:creator

• Mrstik, Bernard Joseph

• Thin films
• rare earth impurities in metals
• superconducting films

Statement dc:rights

• © 1973 Bernard Joseph Mrstik

Language dc:language

en

Identifier

2516869

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/29598