TRICRITICAL POINT AND SUPERFLUID TRANSITION IN HE-3-HE-4 MIXTURES IN SILICA AEROGEL

Citation
M. Paetkau et Jr. Beamish, TRICRITICAL POINT AND SUPERFLUID TRANSITION IN HE-3-HE-4 MIXTURES IN SILICA AEROGEL, Physical review letters, 80(25), 1998, pp. 5591-5594
Citations number
21
Categorie Soggetti
Physics
Journal title
ISSN journal
00319007
Volume
80
Issue
25
Year of publication
1998
Pages
5591 - 5594
Database
ISI
SICI code
0031-9007(1998)80:25<5591:TPASTI>2.0.ZU;2-#
Abstract
We have ultrasonically studied He-3-He-4 mixtures in 87% porosity aero gel. We find only a single transition for He-3-rich mixtures, in contr ast to the detached phase separation curve seen in 98% porosity aeroge l. However, it is a continuous transition, much like the superfluid tr ansition seen in He-4 films on aerogels, rather than a first-order pha se separation as seen in bulk mixtures. A kink occurs in the lambda li ne of the phase diagram at a He-3 concentration (corrected for the He- 4 inert layer) of X-c = 0.51 and is accompanied by a change in the cou pling to the superfluid component, indicating two distinct superfluid morphologies.