33 research outputs found
Melting curve of He: no sign of the supersolid transition down to 10 mK
We have measured the melting curve of He in the temperature range from 10
to 400 mK with the accuracy of about 0.5 bar. Crystals of different
quality show the expected -dependence in the range from 80 to 400 mK
without any sign of the supersolid transition, and the coefficient is in
excellent agreement with available data on the sound velocity in liquid He
and on the Debye temperature of solid He. Below 80 mK we have observed a
small deviation from -dependence which however cannot be attributed to the
supersolid transition because instead of decrease the entropy of the solid
rather remains constant, about Comment: 4 pages, 2 figures, published in Physical Review Letter
Experimental setup for the observation of crystallization waves in He-3
At low temperatures helium crystals can grow and melt so fast that a meltingfreezing wave may propagate along the liquid-solid interface. In He-4 these crystallization waves have been observed at temperatures below 0.5 K. The required temperature for the observation of the crystallization waves in He-3 is predicted to be about 0.2 mK. In order to reach such low temperature at the melting pressure of He-3, special care has to be taken in the design of the experimental cell. Here we present the draft of the experimental cell which is designed for observation of the crystallization waves in He-3
Cavitation in superfluid helium-4 at low temperature
We have studied the nucleation of bubbles in pure superfluid helium-4 at
temperatures
down to 65 mK. We have found that the nucleation is a stochastic process,
and that at
temperatures below 600 mK the nucleation rate is independent of
temperature. These
results are consistent with the assumption that the nucleation takes place
via quantum tunneling