Abstract
The transition to superfluidity of 3He in high porosity (98.2%) aerogel has been observed by nuclear magnetic resonance techniques. The onset of the transition at all pressures above 13 bar is marked by a sharp increase in NMR frequency similar to that observed in bulk 3He-A. This suggests that the aerogel/superfluid phase is highly homogeneous although both the transition temperature, Tc, and the amplitude of the order parameter are substantially suppressed. The aerogel strands are ~ 50Å in diameter, much smaller than the superfluid coherence length. Consequently, we have attempted to interpret our observations as an impurity scattering problem. Based on our measurements of the magnetic field dependence of Tc it appears that both magnetic and potential scattering play important roles where the magnetic scattering can be associated with solid 3He on the aerogel surface. This is determined by isotopic exchange with 4He, a process which appears to stabilize a new superfluid state similar to the bulk B-phase.
Original language | English (US) |
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Pages (from-to) | 2989-2994 |
Number of pages | 6 |
Journal | Czechoslovak Journal of Physics |
Volume | 46 |
Issue number | SUPPL. 6 |
DOIs | |
State | Published - 1996 |
ASJC Scopus subject areas
- General Physics and Astronomy