High-pressure Raman study of CeO/sub 2/ to 35 GPa and pressure-induced phase transformation from the fluorite structure

Journal Article · Tue Mar 15 00:00:00 EST 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.37.4250· OSTI ID:5251097

Kourouklis, G A; Jayaraman, A; Espinosa, G P

Cerium dioxide (CeO/sub 2/), which crystallizes in the fluorite structure, has been studied by high-pressure Raman spectroscopy with use of a diamond anvil cell, up to 35 GPa. The pressure shift of the first-order fluorite Raman peak (F/sub 2//sub g/) and the shifts of several second-order features were measured. The Grueneisen parameter for the F/sub 2//sub g/ mode (465 cm/sup -1/) is obtained as ..gamma.. = 1.44 and for the F/sub 1//sub u/ (..omega../sub LO/ = 585 cm/sup -1/) as ..gamma.. = 1.5;the latter from the 2..omega../sub LO/ shift in the second-order spectrum. Near 31 GPa, a phase transition occurs and six new Raman peaks appear. By comparison with the high-pressure phases of alkaline-earth difluorides, the high-pressure phase is believed to be of the PbCl/sub 2/-type structure. The high-pressure phase is found to be metastable over a 20-GPa interval, but completely reverses on releasing pressure

• Research Organization: AT and T Bell Laboratories, Murray Hill, New Jersey 07974-2070
• OSTI ID: 5251097
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 37:8
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CERIUM OXIDES
CRYSTAL-PHASE TRANSFORMATIONS
CRYSTAL STRUCTURE
FLUORITE
GRUENEISEN CONSTANT
LATTICE PARAMETERS
PRESSURE DEPENDENCE
RAMAN SPECTRA
VERY HIGH PRESSURE
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM FLUORIDES
CALCIUM HALIDES
CERIUM COMPOUNDS
CHALCOGENIDES
FLUORIDES
FLUORINE COMPOUNDS
HALIDE MINERALS
HALIDES
HALOGEN COMPOUNDS
MINERALS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
RARE EARTH COMPOUNDS
SPECTRA
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies