Abstract
The effect of impurity scattering on the phase diagram of pure superfluid has been investigated by acoustic techniques near the bulk polycritical pressure. Impurities were introduced with a porous silica aerogel. In zero applied field, the equilibrium phase is a phase, consistent with predictions from isotropic scattering. The superfluid transition in a magnetic field at 25 bars is from normal to phase and is independent of the magnetic field up to 2.9 kG. A first-order phase transition between and superfluids is observed with surprisingly strong supercooling in both zero and nonzero applied field.
- Received 27 February 2001
DOI:https://doi.org/10.1103/PhysRevLett.87.035701
©2001 American Physical Society