Observation of a superfluid phase in solid helium
Abstract
Evidence of a superfluid liquid phase present in polycrystalline helium at a temperature of 0.2 K and a pressure of 51 bar has been obtained by means of inelastic neutron scattering. The superfluid component is absent at a temperature of 0.6 K and the same pressure. Thus, a “solid helium-superfluid helium” phase transition has been discovered. The sample of solid helium in a porous medium (silica aerogel) has been prepared with the use of a capillary blocking technique. The shape of the structure factor of the superfluid phase indicates the presence of clusters or the effects of a restricted geometry. The results may be used to explain the nonclassical rotational inertia phenomenon in solid helium (often referred to as supersolidity, Nature, 2004).
- Publication:
-
Soviet Journal of Experimental and Theoretical Physics Letters
- Pub Date:
- August 2008
- DOI:
- 10.1134/S0021364008110118
- Bibcode:
- 2008JETPL..87..645K
- Keywords:
-
- 61.12.Ex;
- 67.40.-w