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Phase transitions and compressibility of NaMgF 3 (Neighborite) in perovskite‐ and post‐perovskite‐related structures
Author(s) -
Martin C. David,
Crichton Wilson A.,
Liu Haozhe,
Prakapenka Vitali,
Chen Jiuhua,
Parise John B.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl026150
Subject(s) - perovskite (structure) , post perovskite , silicate perovskite , diamond anvil cell , diffraction , discontinuity (linguistics) , compressibility , amorphous solid , materials science , phase (matter) , mineralogy , crystallography , x ray crystallography , mantle (geology) , geology , thermodynamics , optics , chemistry , geophysics , physics , mathematical analysis , mathematics , organic chemistry
Monochromatic x‐ray diffraction data collected in‐situ within the diamond anvil cell show perovskite structured Neighborite (NaMgF 3 ) transforms to the CaIrO 3 ‐type post‐perovskite structure between 28 and 30 GPa. Upon laser heating, the CaIrO 3 ‐type structure transforms further to an unknown structure ( Pnnm , designated N‐phase). Upon pressure release, N‐phase NaMgF 3 becomes x‐ray amorphous. A structure transformation in post‐perovskite MgSiO 3 and MgGeO 3 to N‐phase may account for previous observations of extra x‐ray reflections during high pressure experiments and tomographic observations of an additional boundary in the lower mantle below the D″ discontinuity.