Sound propagation in /sup 3/He-/sup 4/He mixtures near the superfluid transition

Journal Article · Sat Jul 01 04:00:00 EDT 1978 · J. Low Temp. Phys.; (United States)

DOI:https://doi.org/10.1007/BF00116907· OSTI ID:6732731

Roe, D B; Meyer, H; Ikushima, A

Measurements of the acoustic attenuation and dispersion in liquid /sup 3/He-/sup 4/He mixtures near the superfluid transition T/sub lambda/(X) are reported. The frequency range is ..omega../2..pi..=1-45 MHz and the /sup 3/He mole fraction X of the mistures is 0.007, 0.05, 0.15, and 0.36. Comparisons are made with the measurements of Buchal and Pobell for similar mixtures obtained in the kHz region, and on the whole, the consistency between the two experiments is very satisfactory. An analysis is then performed using both the kHz and MHz data. In the normal phase, where the energy both the kHz and MHz data. In the normal phase, where the energy dissipation is caused by order parameter fluctuations having a lifetime tau/sub F/, the attenuation data can all be scaled according to the expression ..cap alpha..=..cap alpha.. (T/sub lambda/) f (..omega..tau). Here ..cap alpha.. (Tlambda) proportional..omega../sup 1(y/, with y being a function of the mole fraction X and tau/sub F/proportional (T-Tlambda)/sup -x/, with x increasing weakly with X. In the superfluid phase, we attempt a similar scaling representation, which is found to be fairly successful, but where x (T-T/sub lambda/) is roughly 15% larger than x (T>T/sub lambda/). In the superfluid phase we also analyze the attenuation data, assuming the additivity of relaxation and fluctuation-dissipation mechanism, and discuss the relaxation times so derived. In contrast to the attenuation, the dispersion data cannot be brought satisfactorily into a scaling representation. However, at T/sub lambda/, we find U (..omega..)-U (0) proportional..omega../sup y/ as predicted by Kawasaki, where y is in good agreement with the values from attenuation experiments.

• Research Organization: Department of Physics, Duke University, Durham, North Carolina
• OSTI ID: 6732731
• Journal Information: J. Low Temp. Phys.; (United States), Journal Name: J. Low Temp. Phys.; (United States) Vol. 32:1; ISSN JLTPA
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATTENUATION
DISPERSION RELATIONS
DISPERSIONS
ENERGY LOSSES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FREQUENCY RANGE
HELIUM 3
HELIUM 4
HELIUM II
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
MHZ RANGE
MHZ RANGE 01-100
MIXTURES
NUCLEI
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SOLUTIONS
SOUND WAVES
STABLE ISOTOPES
SUPERFLUIDITY
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE