科研之友
微信
新浪微博
Facebook
分享链接
摘要
We have studied the elasticity of solid He-4 in relation with its possible supersolidity. For this we have measured acoustic resonance frequencies in a 1 cm(3) cell filled either with polycrystals or with single crystals of He-4. We have observed a large stiffening at low temperature as first observed by Day and Beamish in polycrystals. The He-3 impurity content has been varied from 300 ppb to 0.4 ppb. When kept in equilibrium with liquid helium, single crystals should be impurity free. In these crystals, a large stiffening is observed, which should not be the result of the pinning of dislocations by impurities.
- 出版日期2010-2
