XAFS study of GeO2 glass under pressure

O. Ohtaka, A. Yoshiasa, H. Fukui, K. Murai, Maki Okube, H. Takebe, Y. Katayama, W. Utsumi

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Abstract

Using a large-volume high-pressure apparatus, Li2O-4GeO2 glass and pure GeO2 gel have been compressed to 14 GPa at room temperature and their local structural changes have been investigated by an in situ XAFS (x-ray absorption fine-structure) method. On compression of Li2O-4GeO2 glass, the Ge-O distance gradually becomes short below 7 GPa, showing the conventional compression of the GeO4 tetrahedron. Abrupt increase in the Ge-O distance occurs between 8 and 10 GPa, which corresponds to the coordination number (CN) changing from 4 to 6. The CN change is completed at 10 GPa. On decompression, the reverse transition occurs gradually below 10 GPa. In contrast to the case for Li2O-4GeO2 glass, the Ge-O distance in GeO2 gel gradually increases over a pressure range from 2 to 12 GPa, indicating that continuous change in CN occurs. The Ge-O distance at 12 GPa is shorter than that of Li-4GeO2 indicating that the change in CN is not completed even at this pressure. On complete release of pressure, the Ge-O distance reverts to that of the starting gel.

Original languageEnglish
Pages (from-to)10521-10524
Number of pages4
JournalJournal of Physics Condensed Matter
Volume14
Issue number44 SPEC ISS.
DOIs
Publication statusPublished - 2002 Nov 11

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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    Ohtaka, O., Yoshiasa, A., Fukui, H., Murai, K., Okube, M., Takebe, H., Katayama, Y., & Utsumi, W. (2002). XAFS study of GeO2 glass under pressure. Journal of Physics Condensed Matter, 14(44 SPEC ISS.), 10521-10524. https://doi.org/10.1088/0953-8984/14/44/326