Shear-viscosity measurements of liquid sup 3 He- sup 4 He mixtures near the tricritical point

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5314415

Howald, C D

This dissertation describes the measurements done of ({rho}{sub n}{eta}), the product of the normal fluid density and the shear viscosity, of {sup 3}He-{sup 4}He mixtures. The emphasis of the experiment was on the range of {sup 3}He molar concentrations, {Chi}, between 64% and 74%. Additional concentrations studied included {Chi} = 0%, 0.1%, 1.1%, and 50%. The cryostat used is described as well as the experimental technique used. The data for pure {sup 4}He is compared to previous results obtained respectively by Bruschi, Biskeborn, and Wang. The data is compared with theory work done by Ferrell in the normal phase, and by Schloms and Dohm in both the normal and superfluid phases. The two dilute mixtures, 0.1% and 1.1%, extended the range of attainable temperatures to colder values by decreasing the superfluid heat leak along the capillary. These data are compared to viscosity data of pure {sup 4}He from Heikkila, Stass, Tough, Woods, and Zinov'eva. The 50% mixture provided a second concentration for comparison with data by Wang and allowed us to check for dissipative modes observed by Wang for {Chi} {ge} 20%. Data for a systematic survey of mixtures near the tricritical point ({Chi}{sub t} = 0.675 and T{sub t} = 0.867K) is also presented showing the absence of a weak singularity in {eta}, unlike the behavior near the liquid-vapor critical line of mixtures. The viscosity of these mixtures is dominated by the background viscosity of the Fermi liquid {sup 3}He approximately 1.3K. This manifests itself by an increasing trend in {eta} for decreasing temperature in this range.

• Research Organization: Duke Univ., Durham, NC (United States)
• OSTI ID: 5314415
• Country of Publication: United States
• Language: English

Related Subjects

665420* -- Superfluidity-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COMPARATIVE EVALUATIONS
CONTROL EQUIPMENT
CRITICAL TEMPERATURE
CRYOSTATS
EQUIPMENT
EVALUATION
EVEN-EVEN NUCLEI
FLUIDS
HELIUM 4
HELIUM II
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
QUANTUM FLUIDS
SHEAR
STABLE ISOTOPES
SUPERFLUIDITY
THERMODYNAMIC PROPERTIES
THERMOSTATS
TRANSITION TEMPERATURE
VISCOSITY