Stability of superfluid 3He-B in compressed aerogel.
In recent work, it was shown that new anisotropic p-wave states of superfluid (3)He can be stabilized within high-porosity silica aerogel under uniform positive strain. In contrast, the equilibrium phase in an unstrained aerogel is the isotropic superfluid B phase. Here we report that this phase stability depends on the sign of the strain. For a negative strain of ∼ 20% achieved by compression, the B phase can be made more stable than the anisotropic A phase, resulting in a tricritical point for A, B, and normal phases with a critical field of ∼ 100 mT. From pulsed NMR measurements, we identify these phases and the orientation of the angular momentum.
Northwestern University, Evanston, Illinois 60208, USA.
J I A
JI
Li
Northwestern University, Evanston, Illinois 60208, USA.
A M
AM
Zimmerman
Northwestern University, Evanston, Illinois 60208, USA.
J
J
Pollanen
Northwestern University, Evanston, Illinois 60208, USA.
C A
CA
Collett
Northwestern University, Evanston, Illinois 60208, USA.
W J
WJ
Gannon
Northwestern University, Evanston, Illinois 60208, USA.
W P
WP
Halperin