Thermal Conductivity of Superfluid 3He-B in a Tubular Channel Down to 0.1Tc at the 4He Crystallization Pressure
We studied the thermal conductivity of superfluid 3 He in a 2.5-mm effective diameter and 0.15-m-long channel connecting the two volumes of our experimental assembly. The main volume contained pure solid 4 He, pure liquid 3 He and saturated liquid 3 He– 4 He mixture at varying proportions, while the...
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Veröffentlicht in: | Journal of low temperature physics 2020, Vol.201 (1-2), p.128-138 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | We studied the thermal conductivity of superfluid
3
He in a 2.5-mm effective diameter and 0.15-m-long channel connecting the two volumes of our experimental assembly. The main volume contained pure solid
4
He, pure liquid
3
He and saturated liquid
3
He–
4
He mixture at varying proportions, while the separate heat-exchanger volume housed sinter and was filled by liquid
3
He. The system was cooled externally by a copper nuclear demagnetization stage, and, as an option, internally by the adiabatic melting of solid
4
He in the main volume. The counterflow effect of superfluid just below the transition temperature
T
c
resulted in the highest observed conductivity about five times larger than that of the normal fluid at the
T
c
. Once the hydrodynamic contribution had practically vanished below
0.5
T
c
, we first observed almost constant conductivity nearly equal to the normal fluid value at the
T
c
. Finally, below about
0.3
T
c
, the conductivity rapidly falls off toward lower temperatures. |
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ISSN: | 0022-2291 1573-7357 |
DOI: | 10.1007/s10909-019-02305-4 |