Abstract/Details

Helium-4 and helium-3/helium-4 mixture films on Nuclepore and hydrogen


1999 1999

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Abstract (summary)

This work extends the study of helium films with the description of two experiments performed on different substrates. The primary experiment involves 4He and 3He-4He mixture films on a solid H2 substrate. The secondary experiment is concerned with the behavior of mixture films on Nuclepore.

The substrate for the helium-on-hydrogen experiment was chosen for the weak binding potential for helium on hydrogen. Unlike most substrates, H 2 will support a superfluid 4He film less dense than a single bulk-density atomic layer. In recent years, interesting effects have been observed for helium-on-hydrogen systems.

The H2 experiment is presented with the results of quartz crystal microbalance measurements and attempted third sound measurements. The quartz crystal microbalance technique measures mass coupling and reveals several interesting features in monolayer and submonolayer helium films on H2. Submonolayer superfluidity and possible phase separation of two-dimensional submonolayer 4He films on solid H2 is reported. 3He–4He mixture films on the H2 substrate reveal novel dependence of the Kosterlitz-Thouless transition temperature on 3He coverage and an unexpected feature at lower temperature.

Third sound resonance and NMR measurements are reported for the Nuclepore experiment. The Nuclepore experiment is the continuation of a long-term study of multilayer 3He-4He mixture films. NMR relaxation times, magnetization, and spin diffusion measurements are discussed over a range of temperatures and mixture film coverages. Third sound measurements taken at the same mixture film coverages reveal interesting structure as a function of temperature. Third sound frequency data at temperatures near 150 mK and at 3He coverages greater than one atomic layer exhibit a local maximum that responds to changes in both 3He and 4He coverage.

Indexing (details)


Subject
Condensation
Classification
0611: Condensation
Identifier / keyword
Pure sciences, Helium films, Hydrogen, Nuclepore
Title
Helium-4 and helium-3/helium-4 mixture films on Nuclepore and hydrogen
Author
Finley, Paul T.
Number of pages
326
Publication year
1999
Degree date
1999
School code
0118
Source
DAI-B 60/05, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780599328846, 0599328843
Advisor
Hallock, Robert B.
University/institution
University of Massachusetts Amherst
University location
United States -- Massachusetts
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
9932310
ProQuest document ID
304516584
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304516584
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