Effect of Crystal Growth Rate on Liquid-like Droplets Formation in the hcp Solid Helium
Abstract
The samples of hcp solid helium (1% 3He in 4He) are studied by NMR technique. The samples are grown by the blocking capillary method at different growth rates (about 8, 2, and 0.08 mK/s). The NMR technique is used for phase identification by measurements of the diffusion coefficient D and the spin-spin relaxation time T2 at temperatures of 1.3-2.0 K and pressures of 34-36 bar. Along with D and T2 for the hcp phase, we simultaneously observe the D and T2 typical for a liquid at growth rates 8 and 2 mK/s. It means that liquid-like inclusions are quenched from the melting curve during fast crystallization of the samples. It is also shown that the slower growth rate corresponds to a smaller size of liquid-like droplets. It results from lower spatially restricted values of D and, finally, absence of these inclusions at the longest crystallization times. The diffusion coefficient measured for liquid-like droplets is also decreasing during the NMR experiment at constant temperature which indicates the reduction of the size of these droplets. Liquid-like droplets are shown to disappear after sample annealing near the melting curve.
- Publication:
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Journal of Physics Conference Series
- Pub Date:
- December 2012
- DOI:
- 10.1088/1742-6596/400/1/012049
- arXiv:
- arXiv:1106.6135
- Bibcode:
- 2012JPhCS.400a2049M
- Keywords:
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- Condensed Matter - Other Condensed Matter
- E-Print:
- 4 pages, 3 figures, LT26 Conference