Behavior of the thermal conductivity of dilute sup 3 He- sup 4 He mixtures in the superfluid phase

Journal Article · Fri Sep 01 04:00:00 EDT 1989 · Physical Review (Section) B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.40.4306· OSTI ID:5507749

Chui, T C.P.; Lipa, J A ^[1]

---

1. Department of Physics, Stanford University, Stanford, California 94305 (US)

We present a new solution to the Khalatnikov two-fluid hydrodynamic equations which suggests that thermal conduction experiments in superfluid {sup 3}He-{sup 4}He mixtures measure the diffusive conductivity. This implies that for small {sup 3}He concentrations the measured conductivity approaches a constant. The singular behavior predicted by Khalatnikov's original solution can be eliminated using a constraint imposed by the tight coupling of concentration and temperature gradients. Microscopically, we find that diffusive mass transport in bulk superfluid is limited by the ability of the diffusing atoms to get rid of the thermodynamic diffusion energy they carry, leading to an apparent diffusivity which can be much smaller that the isothermal mass diffusivity. We also describe a preliminary experiment to observe two effects predicted by our analysis. In agreement with our predictions, we find that (1) the thermal relaxation time in dilute mixtures is very long and (2) the temperature gradient in a superfluid mixture is caused by {sup 3}He mass diffusion. The latter observation gives rise to a new technique for measuring the effective thermal conductivity which avoids the main difficulties encountered by the previous method.

• OSTI ID: 5507749
• Journal Information: Physical Review (Section) B: Condensed Matter; (USA), Journal Name: Physical Review (Section) B: Condensed Matter; (USA) Vol. 40:7; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BINARY MIXTURES
CORRELATIONS
DISPERSIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FLUIDS
HELIUM 3
HELIUM 4
HELIUM II
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
MASS TRANSFER
MIXTURES
NUCLEI
PHYSICAL PROPERTIES
QUANTITY RATIO
QUANTUM FLUIDS
STABLE ISOTOPES
SUPERFLUIDITY
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES