Regensburg 2004 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 17: Postersitzung II: Transport, Quantenkoh
ärenz, Quantenflüssigkeiten
TT 17.30: Poster
Dienstag, 9. März 2004, 14:30–19:00, Poster A
Pressure Driven 3He Flow Through Submicron Sized Apertures — •S.V. Pereverzev and G. Eska — Physikalisches Institut, Universität Bayreuth
The flow of liquid 3He through two different weak link structures was investigated at temperatures of T< 1 mK to 1 K by measuring the characteristic time τ which was needed for pressure equilibration between two volumes connected by the weak links. For the flow through a regular structure of 65x65 holes of 150 nm dia. in a 50 nm thick SiN membrane we observed the expected T-dependence and the transition from Knudsen to viscous flow behavior. To the contrary, no T-dependence was found for normal fluid 3He-flow through 105 holes of 15 nm diameter, statistically distributed over a 14 nm thick nitrocellulose film. Below the superfluid transition the relaxation rate (1/τ ∼flow-channel conductance) increased by orders of magnitude for both types of weak links. Our data are in qualitative agreement with experiments by other groups. We present a model which describes our normal flow results quantitatively for the 150 nm aperture, but which does not explain the flow through the 15 nm holes.