Fermi liquid behaviour of the viscosity of {sup 3}He-{sup 4}He mixtures

Journal Article · Tue Nov 01 04:00:00 EST 1994 · Journal of Low Temperature Physics

DOI:https://doi.org/10.1007/BF00752920· OSTI ID:98788

Koenig, R; Pobell, F ^[1]

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1. Universitaet Bayreuth (Germany)

We have investigated {sup 3}He-{sup 4}He mixtures at {sup 3}He-concentrations 0.98% {le} x {le} 9.5% by the vibrating wire technique in the temperature range 1 mK {le} T {le} 100 mK and at pressures 0 bar {le} p {le} 20 bar. In the degenerate regime of the mixtures the Landau theory of Fermi liquids predicts a temperature dependence of the viscosity {eta} proportional T{sup {minus}1}. We report on the first observation of this behaviour at 3 mK {le} T {le} 10 mK for all investigated concentrations and pressures. At temperatures below about 20 mK slip corrections had to be taken into account due to the increase of the quasiparticle mean free path at very low temperatures. The low-temperature cut-off in {eta} T{sup 2} = constant indicates the transition into the ballistic regime of the mixtures, where the mean free path of the quasiparticles exceeds the radius of the vibrating wire. Our results for the pressure dependence of the viscosity as well as for its magnitude show substantial differences from predictions based on pseudopotential theory. However, a calculation of {eta} with the quasiparticle interaction potential of recent solubility measurements in mixtures agrees well with our experimental data, in particular the pressure independence of {eta}.

• OSTI ID: 98788
• Journal Information: Journal of Low Temperature Physics, Journal Name: Journal of Low Temperature Physics Journal Issue: 3-4 Vol. 97; ISSN JLTPAC; ISSN 0022-2291
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
EXPERIMENTAL DATA
FERMI GAS
HELIUM 3
HELIUM 4
LANDAU LIQUID HELIUM THEORY
MIXTURES
TEMPERATURE DEPENDENCE
VISCOSITY