Gravity-induced diffusion of isotope atoms in monoatomic solid SeT. Mashimo1, 2, M. Ono2, X. S. Huang1, Y. Iguchi1, S. Okayasu2, K. Kobayashi3 and E. Nakamura3
1 Shock Wave and Condensed Matter Research Center, Kumamoto University - Kurokami-cho, Kumamoto 860-8555, Japan
2 Advanced Science Research Center, Japan Atomic Energy Agency - Tokai-mura, Nakagun, Ibaraki 319-1195, Japan
3 Institute for Study of the Earth's Interior, Okayama University - Misasa-cho, Tottri 682-0193, Japan
received 9 October 2007; accepted in final form 9 January 2008; published March 2008
published online 19 February 2008
A strong gravitational field resulted in the gravity-induced diffusion (sedimentation) of isotope atoms in monoatomic solid Se. The layer crystalline morphology consisting of three zones of the fine-grained crystals, the long crystals and feather-shaped crystals grown parallel to gravity direction appeared in the specimen ultracentrifuged at (0.8-1)106 G and at 190 °C. Change in the concentration ratio 82Se/76Se of > 0.8% was observed in the grown crystalline region. These results show an evidence for the sedimentation of substitutional atoms in solids via self-diffusion, and suggest the possibility of application to the control of impurity and crystalline states as well as to isotope separation.
67.80.dj - Defects, impurities, and diffusion.
47.57.ef - Sedimentation and migration.
66.30.Fq - Self diffusion in metals, semimetals, and alloys .
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