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Structure of δ1-CoZn7.8 an example of a phason pinning-unpinning transformation?

Lind, Hanna ; Boström, Magnus ; Petříček, Vaclav and Lidin, Sven LU (2003) In Acta Crystallographica. Section B: Structural Science 59(6). p.720-729
Abstract

The novel structure of the δ1 phase in the cobalt-zinc system was determined by single-crystal X-ray diffraction. The structure features fused double icosahedra linked by edge-and face-sharing. The δ1-CoZn7.8 structure is incommensurately modulated along the columnar b direction. The extent of the linear pentagonal antiprismatic intergrowth is limited to a maximum of two overlapping icosahedra because of geometric demands and radii relations. Even this limited fusion of icosahedra leads to strain that is believed to be the origin of the structural modulation. The compound was synthesized using a centrifugation-aided filtration method which yielded single crystals grown on cobalt pieces in a zinc-rich... (More)

The novel structure of the δ1 phase in the cobalt-zinc system was determined by single-crystal X-ray diffraction. The structure features fused double icosahedra linked by edge-and face-sharing. The δ1-CoZn7.8 structure is incommensurately modulated along the columnar b direction. The extent of the linear pentagonal antiprismatic intergrowth is limited to a maximum of two overlapping icosahedra because of geometric demands and radii relations. Even this limited fusion of icosahedra leads to strain that is believed to be the origin of the structural modulation. The compound was synthesized using a centrifugation-aided filtration method which yielded single crystals grown on cobalt pieces in a zinc-rich melt. The (3 + 1)-dimensional superspace group is F2/m(0β0)s0 and the modulation wavevector was determined to q = 0.234b*. The partial amorphization of the sample when subjected to mechanical grinding is an indication of a metastable structure. The incommensurability of the structure may be seen as an ordered pinning of phasons.

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author
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publishing date
type
Contribution to journal
publication status
published
in
Acta Crystallographica. Section B: Structural Science
volume
59
issue
6
pages
10 pages
publisher
International Union of Crystallography
external identifiers
  • scopus:2442651863
ISSN
0108-7681
DOI
10.1107/S0108768103019694
language
English
LU publication?
no
id
8066f868-3245-40d7-b6de-05e617ff2dfd
date added to LUP
2019-04-08 15:28:57
date last changed
2025-01-09 05:58:00
@article{8066f868-3245-40d7-b6de-05e617ff2dfd,
  abstract     = {{<p>The novel structure of the δ<sub>1</sub> phase in the cobalt-zinc system was determined by single-crystal X-ray diffraction. The structure features fused double icosahedra linked by edge-and face-sharing. The δ<sub>1</sub>-CoZn<sub>7.8</sub> structure is incommensurately modulated along the columnar b direction. The extent of the linear pentagonal antiprismatic intergrowth is limited to a maximum of two overlapping icosahedra because of geometric demands and radii relations. Even this limited fusion of icosahedra leads to strain that is believed to be the origin of the structural modulation. The compound was synthesized using a centrifugation-aided filtration method which yielded single crystals grown on cobalt pieces in a zinc-rich melt. The (3 + 1)-dimensional superspace group is F2/m(0β0)s0 and the modulation wavevector was determined to q = 0.234b*. The partial amorphization of the sample when subjected to mechanical grinding is an indication of a metastable structure. The incommensurability of the structure may be seen as an ordered pinning of phasons.</p>}},
  author       = {{Lind, Hanna and Boström, Magnus and Petříček, Vaclav and Lidin, Sven}},
  issn         = {{0108-7681}},
  language     = {{eng}},
  month        = {{12}},
  number       = {{6}},
  pages        = {{720--729}},
  publisher    = {{International Union of Crystallography}},
  series       = {{Acta Crystallographica. Section B: Structural Science}},
  title        = {{Structure of δ<sub>1</sub>-CoZn<sub>7.8</sub> an example of a phason pinning-unpinning transformation?}},
  url          = {{http://dx.doi.org/10.1107/S0108768103019694}},
  doi          = {{10.1107/S0108768103019694}},
  volume       = {{59}},
  year         = {{2003}},
}