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Morphology and growth kinetics of He-3 crystals below 1 mK.

Research output: Contribution to journalJournal article

Published

  • Viktor Tsepelin
  • Harry Alles
  • Alexei Babkin
  • Reyer Jochemsen
  • Alexander Y. Parshin
  • Igor A. Todoshchenko
Journal publication date12/2002
JournalJournal of Low Temperature Physics
Journal number5-6
Volume129
Number of pages42
Pages489-530
Original languageEnglish

Abstract

The shapes as well as the growth and melting properties of bcc-He-3 single crystals have been investigated with a low temperature Fabry-Perot interferometer. Eleven types of facets were clearly identified during slow crystal growth at the temperature of 0.55 mK, where the solid is in the antiferromagnetically ordered u2d2 phase. The growth rates of the individual facets have been measured and the results indicate significant growth anisotropy. The observed linear dependence of the growth velocity on the driving force shows that facets grow due to the presence of screw dislocations, while the step velocity is limited by the spin wave velocity due to the strong interaction of the moving step with magnons in the solid. The measured growth rates of the facets and the assumed growth mechanism gave us the unique opportunity to obtain the step free energies for ten different types of facets observed during a single growth sequence. The dependence of the free energy of the step on the step height is compared with predictions of the weak- and strong-coupling models. Our results suggest that He-3 crystals have rather strong coupling of the liquid/solid interface to the crystal lattice and that the step-step interactions are of elastic origin.