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Abstracts
P3.26
Search for spatially-modulated phases in confined superfluid
3
He
Lev V. Levitin(1), Nikolay Zhelev(2,3), Robert G. Bennett(2,4), Jeevak M.
Parpia(2), Andrew J. Casey(1), John Saunders(1)
1) Department of Physics, Royal Holloway, University of London, UK
2) Department of Physics, Cornell University, USA
3) Now at Corning Incorporated, USA
4) Now at Vantage Power Ltd, UK
Superfluidity in
3
He arises via p-wave pairing, and the rich order parameter
structure allows for multiple superfluid phases. It is predicted that confinement
to a slab of thickness of order 10 coherence lengths will, near the A-B transition,
trigger the spontaneous appearance of domain walls between regions of superfluid
B phase with different orientation, creating a spatially-modulated (striped) phase.
Our NMR measurements on a 1.1 um slab of
3
He at low pressure disagree both
with the NMR signatures of single-domain B phase, and a periodic stripe phase.
However they can be explained by a spatially-modulated phase with domain
structure supporting unequal amounts of different domains.
P3.27
Suppression of Tc and gap of superfluid
3
He by confinement in a 200
nm slab geometry
Heikkinen Petri(1), Casey Andrew(1), Levitin Lev(1), Parpia Jeevak(2), Rojas
Xavier(1), Zhelev Nikolay(2), Saunders John(1)
1) Royal Holloway, University of London, Department of Physics, UK
2) Cornell University, Department of Physics, USA
The order parameter of superfluid helium-3 confined in a cavity with height
comparable to the coherence length is dominated by surface pair-breaking. We
describe an accurate determination of the suppression of the superfluid transition
temperature, Tc, in an engineered nanofluidic 200 nm slab at various pressures.
The results are compared to the predictions of quasi-classical theory. We start
from a solid
3
He film on the surfaces, and then tune the surface pair-breaking by
pre-plating them with a solid
4
He film and eventually with a superfluid
4
He film.
Small volumes of bulk
3
He at opposite ends of the cavity mark the unsuppressed
Tc and rule out discrepancies due to temperature gradients.
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