Effect of [sup 4]He on the surface scattering of [sup 3]He

Journal Article · Fri Jan 01 04:00:00 EST 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.47.319· OSTI ID:6817383

Tholen, S M; Parpia, J M ^[1]

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1. Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853-2501 (United States)

We describe and compare the results of two investigations in which the boundary condition for [sup 3]He was altered by the addition of [sup 4]He, which is preferentially confined to the surfaces by virtue of its smaller zero-point motion. In the first experiment, carried out in normal [sup 3]He, we observed an increase of specularity in the slip between [sup 3]He and the polished silicon substrate at a coverage consistent with the onset of superfluidity in the surface [sup 4]He layer. The second experiment was performed on superfluid [sup 3]He confined within the pores of sintered silver. By coating the surfaces with [sup 4]He, we observed a partial restoration of the superfluid fraction and transition temperature, which had been reduced below bulk by finite-size effects. This effect is due to a change from diffuse to specular boundary scattering. We found that the specularity induced by the [sup 4]He was destroyed upon the application of a pressure sufficient to solidify the surface [sup 4]He, confirming the role of surface superfluid [sup 4]He on specular scattering.

• OSTI ID: 6817383
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 47:1; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

665420* -- Superfluidity-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BOUNDARY LAYERS
DEPOSITION
ELEMENTS
EVEN-ODD NUCLEI
HELIUM 3
HELIUM ISOTOPES
ISOTOPES
LAYERS
LIGHT NUCLEI
METALS
NUCLEI
PHASE TRANSFORMATIONS
SCATTERING
SEMIMETALS
SILICON
SILVER
SOLIDIFICATION
STABLE ISOTOPES
SUPERFLUIDITY
SURFACE COATING
TRANSITION ELEMENTS