Velocity of second sound and superfluid density near the superfluid transition in /sup 3/He--/sup 4/He mixtures

Journal Article · Wed Sep 01 00:00:00 EDT 1976 · J. Low Temp. Phys.; (United States)

DOI:https://doi.org/10.1007/BF00657179· OSTI ID:7130486

Uehara, F

Using superleak condenser transducers, the velocity of second sound U/sub 2/ has been measured near the superfluid transition temperature T/sub lambda/ in /sup 3/He--/sup 4/He mixtures with molar concentrations X of /sup 3/He of 0.0, 0.038, 0.122, 0.297, and 0.440. We have obtained the superfluid density rho/sub s/rho from U/sub 2/ on the basis of linearized two-fluid hydrodynamics. The results for rho/sub s//rho are consistent with those obtained from the oscillating disk method, as expected from two-fluid hydrodynamics. The value of rho/sub s//rho at each X could be expressed by a single power law, rho/sub s//rho = k epsilon/sup zeta/, where epsilon = 1--T/T/sub lambda/, within the experimental uncertainty. It is found that the exponent zeta is independent of concentration for X less than or equal to 0.44 within the experimental uncertainty. This concentration independence of zeta is in agreement with the universality concept. From the conclusion that the values of zeta are universal for X less than or equal to 0.44, the concentration dependence of the superfluid component rho/sub s/ is expressed by an empirical equation rho/sub s/(X, epsilon) = psi/sup 2/rho/sub s/(O, epsilon). It is found that psi corresponds to the volume fraction of /sup 4/He in the superfluid /sup 3/He--/sup 4/He mixture. The value of psi is in agreement with that obtained from the measurement of the molar volume by others.

• Research Organization: Tokyo Univ. of Education, Otsuka, Japan
• OSTI ID: 7130486
• Journal Information: J. Low Temp. Phys.; (United States), Journal Name: J. Low Temp. Phys.; (United States) Vol. 24:5/6; ISSN JLTPA
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DISPERSIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FLUID MECHANICS
HELIUM 3
HELIUM 4
HELIUM II
HELIUM ISOTOPES
HYDRODYNAMICS
ISOTOPES
LIGHT NUCLEI
MECHANICS
MIXTURES
NUCLEI
PHYSICAL PROPERTIES
SECOND SOUND
STABLE ISOTOPES
SUPERFLUIDITY
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
VELOCITY