Third sound in /sup 3/He-/sup 4/He mixture films

Journal Article · Sun Jul 01 04:00:00 EDT 1984 · J. Low Temp. Phys.; (United States)

DOI:https://doi.org/10.1007/BF00681456· OSTI ID:6622328

Ellis, F M; Brooks, J S; Hallock, R B

We report third-sound studies of /sup 3/He-/sup 4/He mixture films for 0.3< or approx. =T< or approx. =1.8 K carried out in two different experimental situations. In one experiment detailed measurements of the amplitude of both the temperature and thickness variation of the film were made for pure /sup 4/He and the results for Vertical Bar..delta..T/..delta..dVertical Bar are in good agreement with the predictions of Bergman. Mixture studies in this apparatus were made difficult due to the presence of capillary condensation. In spite of this a number of interesting results are reported. Subsequent measurements were made in a new apparatus where capillary condensation effects could be demonstrably avoided. Helium films of 5.7 layers of /sup 4/He were studied as a function of added amounts of /sup 3/He. Below Tapprox. =Tapprox. =0.7 K the third-sound measurements are consistent with model calculations based on a bilayer film. We conclude that for 0.3< or approx. =T< or approx. =0.6 K films of the type we have studied are isotopically layered in the van der Waals field provided by the substrate.

• Research Organization: Laboratory for Low Temperature Physics, Department of Physics and Astronomy, University of Massachusetts, Amherst, Massachusetts
• OSTI ID: 6622328
• Journal Information: J. Low Temp. Phys.; (United States), Journal Name: J. Low Temp. Phys.; (United States) Vol. 56:1; ISSN JLTPA
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CAPACITORS
DATA
DETECTION
DIAGRAMS
DISPERSIONS
ELECTRICAL EQUIPMENT
EQUIPMENT
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
FILMS
FLUID MECHANICS
FREQUENCY DEPENDENCE
HELIUM 3
HELIUM 4
HELIUM ISOTOPES
HYDRODYNAMICS
INFORMATION
ISOTOPES
LANDAU LIQUID HELIUM THEORY
LAYERS
LIGHT NUCLEI
MECHANICS
MIXTURES
NUCLEI
NUMERICAL DATA
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
STABLE ISOTOPES
TEMPERATURE DEPENDENCE
THIRD SOUND
ULTRALOW TEMPERATURE
VAN DER WAALS FORCES
VELOCITY