Limits of metastability of liquid helium
Frédéric Caupina, Sébastien Balibara, Humphrey J. Marisb
aLaboratoire de Physique Statistique de l'Ecole Normale Supérieure associé aux Universités Paris 6 et Paris 7 et au CNRS, 24 rue Lhomond 75231 Paris Cedex 05, France
bDepartment of Physics, Brown University, Providence, Rhode Island 02912
Helium can remain in the liquid state at a pressure below its saturated vapour pressure or above its melting pressure. This metastability can reach high degrees in helium because of its purity. We review the present knowledge of the stretched liquid state; experiments on cavitation are interpreted in relation to the existence of a liquid-gas spinodal limit. In view of recent experiments, we also consider overpressurized liquid helium 4 and address the question of the stability of the superfluid phase against the solid.
Faceting and growth kinetics of 3He crystals
Harry Allesa, Alexei Babkinb, Reyer Jochemsenc, Alexander Ya. Parshind, Viktor Tsepeline, Igor A. Todoshchenkoa
aLow Temperature Laboratory, Helsinki University of Technology, FIN-02015 HUT, Finland
bDepartment of Physics and Astronomy, UNM, 800 Yale Boulevard NE, Albuquerque, NM 87131, USA
cKamerlingh Onnes Laboratory, Leiden University, 2300RA Leiden, The Netherlands
dP.L. Kapitza Institute for Physical Problems, ul. Kosygina 2, 117334 Moscow, Russia
eDepartment of Physics, Stanford University, Stanford, CA 94305-4060, USA
We have imaged 3He crystals at T < 1 mK and identified more than ten different types of facets. These findings make 3He crystals a good system to study faceting because only three types of facets have been found in both 3He and 4He before our experiments. We present data on faceting and growth kinetics and discuss consequences of our results as well as possible future experiments.
Melting and Growth of Solid 4He by Ultrasound
Y. Suzuki, M. Maekawa, M. Ueno, R. Nomura*, Y. Okuda, S. Burmistrov
Department of Condensed Matter Physics,
Tokyo Institute of Technology,
2-12-1, O-okayama, Meguro, Tokyo 152-8551, Japan
Solid-liquid interface of 4He was prepared between two transducers and ultrasound was applied to it perpendicularly. Solid 4He was grown when the ultrasound was applied to the interface from the solid side and melted from the liquid side at low temperatures below 750mK. Above 750mK it was melted in the both sound directions. These growth and melting are explained qualitatively by the acoustic radiation pressure and the temperature dependent sound transmission coefficients. By using this new way of operating the interface the mobility of the interface was measured in growing and melting cases separately and found to have different values in some crystal orientations.
Hyperbolic roton and solid nucleation in superfluid 4He
Tomoki Minoguchi
Institute of Physics, University of Tokyo, Komaba 3-8-1, Tokyo 153-8902, Japan
The solidification model for superfluid 4He is reviewed, where the symmetry breaking order parameter h is appropriately defined and included in addition to the density change x. As a remarkable feature, the model explicitly shows that the instability to the solid is associated with the instability against the fluctuation of h, namely the softening of 'hyperbolic roton'. The rate W of solid nucleation is calculated based on the model. In contrast to x, h is non-conserved quantity, and then it leads the novel exponents in W near the spinodal pressure.