Amorphization of Ca{sub 3}(VO{sub 4}){sub 2} at high pressure

Journal Article · Sat Aug 01 04:00:00 EDT 1998 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1006/jssc.1998.7826· OSTI ID:653139

Grzechnik, A ^[1]

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1. Ecole Normale Superieure de Lyon (France)

The combined X-ray diffraction and Raman spectroscopy data show that Ca{sub 3}(VO{sub 4}){sub 2} irreversibly amorphizes at 10.0 GPa and room temperature. The amorphization, with its onset at about 8.5 GPa, is not preceded by any phase transition in the crystalline phase, which possesses highly anisotropic compressibility (the axial stiffness along the a axis is over 30% larger than the axial stiffness along the c axis). The results of Raman spectroscopy measurements demonstrate that structural rearrangements in the amorphous Ca{sub 3} (VO{sub 4}){sub 2} occur between 8.1 and 14.8 GPa. This is associated with a large deformation of the VO{sub 4}{sup 3{minus}} units or the increase of the average coordination number for the V{sup 5+} cations in the amorphous material. A large hysteresis of this phase change is observed upon decompression, suggesting a first-order character of polymorphic transitions within the amorphous material.

• OSTI ID: 653139
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 139; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMORPHOUS STATE
CALCIUM OXIDES
EXPERIMENTAL DATA
PHASE STUDIES
PRESSURE DEPENDENCE
RAMAN SPECTROSCOPY
VANADIUM OXIDES
VERY HIGH PRESSURE
X-RAY DIFFRACTION