Surface Tension of SolidHe4

Abstract

The interfacial surface tension and the angle of contact between superfluid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ and bcc and hcp ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ crystals have been measured in the same way as for a free liquid surface. Contrary to expectations, neither crystal is found to "wet" the wall of the container. At 0.4 K the surface tension between hcp ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ and the liquid is 2.5 times larger than that between liquid and vapor.