Superfluid transition of /sup 4/He films adsorbed in porous materials

Journal Article · Thu May 01 04:00:00 EDT 1986 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.33.6106· OSTI ID:5764807

Kotsubo, V; Williams, G A

The superfluid transition of thin /sup 4/He films adsorbed in Al/sub 2/O/sub 3/ packed powders is studied using third-sound techniques. For powder grain sizes down to 500 A, the transition is found to remain a Kosterlitz-Thouless vortex-screening transition. As the powder size is decreased, however, the drop to zero of the areal superfluid density becomes broadened, and the third-sound attenuation decreases. A finite-size model of the Kosterlitz-Thouless transition is formulated to explain these effects. Limiting the maximum vortex pair separation to the powder grain size leads to a broadening of the transition and reduced dissipation if the grain size is smaller than a vortex diffusion length. The model also describes many features of earlier measurements on films adsorbed in porous Vycor glass. The claim that the transition in Vycor films is three dimensional (not involving vortices) is reexamined in light of the present results.

• Research Organization: Physics Department, University of California, Los Angeles, California 90024
• OSTI ID: 5764807
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 33:9; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ATTENUATION
CHALCOGENIDES
EVEN-EVEN NUCLEI
FILMS
FLUIDS
HELIUM 4
HELIUM II
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
MATERIALS
NUCLEI
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
POROUS MATERIALS
POWDERS
QUANTUM FLUIDS
STABLE ISOTOPES
SUPERFLUIDITY
THIRD SOUND
VORTICES