Abstract
Cerium dioxide (), 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 () and the shifts of several second-order features were measured. The Grüneisen parameter for the mode (465 ) is obtained as γ=1.44 and for the ( ) as γ=1.5; the latter from the 2 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 -type structure. The high-pressure phase is found to be metastable over a 20-GPa interval, but completely reverses on releasing pressure.
- Received 17 September 1987
DOI:https://doi.org/10.1103/PhysRevB.37.4250
©1988 American Physical Society