Regensburg 1998 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 21: Postersitzung III: Spin-Peierls-Systeme, Metall-Isolator-Übergang, Lokalisierung; SL: Theorie; Quantenflüssigkeiten und -kristalle; Amorphe Materialien, Tunnelsysteme; Borcarbide, Fullerene, konventionelle SL; SL dünner Filme; Experimentiertechniken
TT 21.50: Poster
Donnerstag, 26. März 1998, 15:00–18:30, D
4He-Crystals at mK-Temperatures — •E. Nazaretski3, J. Ruuti1, P. Hakonen1, A. Babkin1, A. Parshin2, and G. Tvalashvili3 — 1Low Temperature Laboratory, Helsinki University of Technology, 02150 Espoo, Finland. — 2P.Kapiza Institute for Physical Problems, ul.Kosygina 2, 117334, Moscow, Russia — 3Physikalisches Institut, Universität Bayreuth, D–95440 Bayreuth
Liquid-solid interface of 4He has been investigated down to
mK-tempe
ratures using an optical interferometer based on a cooled
CCD-sensor in combination with a sensitive pressure gauge.
The c-facets with 5-50 screw dislocations/cm2 grew with
spiral growth which could be understood by describing the growth
in terms of localized steps, within the framework of standard theory.
Crystals without screw dislocations showed a new growth mechanism.
At rates below 0.5 nm/s the c-facet shows slow, continious growth.
Addition of 3He impurities reduced the speed of all growth modes.
The reduction of a growth speed is not directly proportional to the
concentration of 3He impurities.