Strong orientational effect of stretched aerogel on the (3)He order parameter.
Deformation of aerogel strongly modifies the orientation of the order parameter of superfluid (3)He confined in aerogel. We used a radial squeezing of aerogel to keep the orbital angular momentum of the (3)He Cooper pairs in the plane perpendicular to the magnetic field. We did not find strong evidence for a polar phase, with a nodal line along the equator of the Fermi surface, predicted to occur at large radial squeezing. Instead we observed (3)He-A with a clear experimental evidence of the destruction of the long-range order by random anisotropy-the Larkin-Imry-Ma effect. In (3)He-B we observed and identified new modes of NMR, which are impossible to obtain in bulk (3)He-B. One of these modes is characterized by a repulsive interaction between magnons, which is suitable for the magnon Bose-Einstein condensation.
Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9, France.
J
J
Elbs
Yu M
YM
Bunkov
E
E
Collin
H
H
Godfrin
G E
GE
Volovik