Open AccessStructural changes of quartz‐type crystalline and vitreous GeO 2 under pressure
Author(s) -
Ohtaka Osamu,
Yoshiasa Akira,
Fukui Hiroshi,
Murai Keiichiro,
Okube Maki,
Katayama Yoshinori,
Utsumi Wataru,
Nishihata Yasuo
Publication year - 2001
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049500018306
Subject(s) - quartz , hysteresis , coordination number , x ray absorption fine structure , materials science , crystallography , structural change , chemistry , mineralogy , analytical chemistry (journal) , spectroscopy , composite material , condensed matter physics , ion , physics , organic chemistry , economics , macroeconomics , quantum mechanics
Using a large volume high pressure apparatus, quartz‐type crystalline GeO 2 and Li 2 O‐4GeO 2 glass have been compressed up to 14 GPa at room temperature and their local structural changes have been investigated by an in‐situ XAFS method. In quartz‐type crystalline GeO 2 , the change of the coordination number from 4 to 6 begins above 8 GPa and finishes below 12 GPa. On decompression, reversal transition begins below 8 GPa and there is a large hysteresis. Almost no sixfold coordination of Ge is preserved after releasing pressure. Change of coordination number in vitreous Li 2 O‐4GeO 2 begins above 6 GPa and is completed below 10 GPa. Reversal transition begins below 10 GPa and the hysteresis is smaller than that of quartz‐type GeO 2 . Change of coordination number in vitreous Li 2 O‐4GeO 2 is also reversal.