Measurements of superfluid densities and critical superfluid mass currents of pure /sup 4/He and /sup 3/He//sup 4/He mixtures in nuclepore near the lambda transition

Journal Article · Wed Jul 01 04:00:00 EDT 1981 · J. Low Temp. Phys.; (United States)

DOI:https://doi.org/10.1007/BF00115082· OSTI ID:6006572

Schubert, P C; Zimmermann, W Jr

Measurements have been made of the relative superfluid density rho/sub sp//rho and the critical mass current I/sub sc/ for the onset of dissipation in the superfluid flow of pure /sup 4/He and /sup 3/He//sup 4/He mixtures in the circular cylindrical pores of Nuclepore near the lambda transtion, using a double-ended Helmholtz resonator. Pore diameters of 0.03, 0.1, and 0.4 ..mu..m were studies using /sup 3/He mole fractions of 0.0,-0.2, and approx.0.4. For each pore diameter d/sub p/ and mole fraction x our results for rho/sub sp//rho were fitted relatively well by the form C (t--t/sub 01/)/sup 0.675/ and those for I/sub sc/ by the form I/sub sc0/(t--t/sub 0c/)/sup g/, where t = (T/sub lambda/--T)/T/sub lambda/. for each combination of d/sub p/ and x the reduced onset temperatures t/sub 01/ and t/sub 0c/ are in rough agreement with each other but somewhat larger than values found by others for Nuclepore. For the smaller two pore diameters, these onset temperatures are consistent with the universality hypothesis that near T/sub lambda/, h/sup 2/..pi../sub sb/xi/m/sup 2//sub 4/k/sub B/T should be a constant superfluid density, xi is the coherence length, m/sub 4/ is the /sup 4/He atom mass, k/sub B/ is Boltzmann's constant, and T is the absolute temperature. At each value of x the amplitudes C agree well with the corresponding amplitude for rho/sub sb//rho, and g equals 1.17 +- 0.04 for all cases. Measurements of the velocity of second sound at x = 0.000, 0.190, 0.401, and 0.450 are also reported.

• Research Organization: Tate Laboratory of Physics, University of Minnesota, Minneapolis, Minnesota
• OSTI ID: 6006572
• Journal Information: J. Low Temp. Phys.; (United States), Journal Name: J. Low Temp. Phys.; (United States) Vol. 44:1; ISSN JLTPA
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ADSORPTION
DENSITY
DISPERSIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FLUIDS
HELIUM 3
HELIUM 4
HELIUM II
HELIUM ISOTOPES
ISOTOPES
LAMBDA POINT
LIGHT NUCLEI
MATERIALS
MIXTURES
NUCLEI
PHYSICAL PROPERTIES
POROUS MATERIALS
QUANTUM FLUIDS
SECOND SOUND
SORPTION
STABLE ISOTOPES
SUPERFLUIDITY
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE