Superfluidity in helium films studied with a thin-film oscillator
In this article on measurements of superfluidity in 4He films a detailed report on the construction of the isothermal thin-film Helmholtz oscillator is presented. The design and the performance of the film-thickness transducers are discussed. Measurements of Helmholtz oscillations and low-frequency...
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Published in | Physica B + C Vol. 124; no. 1; pp. 1 - 21 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Amsterdam
Elsevier B.V
01.01.1984
North-Holland |
Subjects | |
Online Access | Get full text |
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Summary: | In this article on measurements of superfluidity in
4He films a detailed report on the construction of the isothermal thin-film Helmholtz oscillator is presented. The design and the performance of the film-thickness transducers are discussed. Measurements of Helmholtz oscillations and low-frequency third-sound phenomena, both excited in the oscillator, are analysed in terms of a phenomenological two-fluid model. When proper account is taken of the flow of mass and energy between the film and its environment, a consistent description of these independent phenomena is obtained. Combining the data derived for the areal superfluid density in the film with the onset data from the thermo-mechanical effect measurements yields strong numerical support for the applicability of the Kosterlitz-Thouless prediction for two-dimensional ordering in very thin films. Finally, also a phase diagram for the mobility of thin films as deduced from the existing experimental evidence is given. |
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ISSN: | 0378-4363 |
DOI: | 10.1016/0378-4363(84)90026-3 |