High-pressure x-ray diffraction study of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CeO</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>to 70 GPa and pressure-induced phase transformation from the fluorite structure

Duclos, Steven J.; Vohra, Yogesh K.; Ruoff, Arthur L.; Jayaraman, A.; Espinosa, G. P.

doi:10.1103/physrevb.38.7755

Cited by 185 publications

(160 citation statements)

References 19 publications

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“…HP studies of cubic CeO 2 indicate that a structural transition to an orthorhombic PbCl 2 -type lattice occurs at 31 GPa. 50,51 The same transition is reported in nanocrystalline CeO 2 at 22.3 GPa. 34,35 A large volume collapse with an increase in coordination number in the metal ions is observed at this transition.…”

Section: Resultssupporting

confidence: 56%

New high-pressure phase and equation of state of Ce2Zr2O8

Errandonea

Kumar

Achary

et al. 2012

Journal of Applied Physics

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Pressure effects on phase equilibria and solid solubility in MgO-Y2O3 nanocomposites J. Appl. Phys. 111, 053506 (2012) Effects of high pressure on the magnetism of ErCo2 J. Appl. Phys. 111, 07E132 (2012) Effect of pressure loading rate on the crystallographic texture of NdFeB nanocrystalline magnets J. Appl. Phys. 111, 07A717 (2012) A fresh look at dense hydrogen under pressure. III. Two competing effects and the resulting intra-molecular H-H separation in solid hydrogen under pressure J. Chem. Phys. 136, 074503 (2012) A reconstruction of cubic rs-ZnO on MgO (200) substrate through (100) plane of w-ZnO:rs-ZnO for transparent electronic application

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Section: Resultssupporting

confidence: 56%

New high-pressure phase and equation of state of Ce2Zr2O8

Errandonea

Kumar

Achary

et al. 2012

Journal of Applied Physics

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“…A literature review for CeO 2 revealed very little theoretical and/or experimental work had been performed on the shock response of solid CeO 2 , and therefore, parameters had to be determined. Diamond anvil cell compaction data from Duclos et al [3], which was fit with a first-order Birch EOS, was used to derive the Hugoniot response of solid CeO 2 . The isothermal compression data up to 30 GPa was first fit with the DugdaleMcDonald model [4] to determine the zero pressure Grüneisen parameter γ 0 , following which it was transformed to the soild Hugoniot using the MieGrüneisen EOS assuming γ 0 /V 0 remains constant.…”

Section: Methodsmentioning

confidence: 99%

“…With the exception of the two highest pressure shots, the powders were pre-compressed into a 25.4 mm ID stainless steel cylinder to a nominal initial density of 4.0 g/cm 3 . The height of the powder was kept constant at 2 mm, and the impactor and driver/base plate materials were both copper.…”

Section: Methodsmentioning

confidence: 99%

“…The height of the powder was kept constant at 2 mm, and the impactor and driver/base plate materials were both copper. For the highest pressure shots the initial density remained 4.0 g/cm 3 , but the impactor and driver materials were Kel-F 81, the powder thickness was 6 mm, and the diameter of the precompacted specimen was 33 mm. In all experiments the impedance matching technique was used to determine the shocked state in the powder.…”

Section: Methodsmentioning

confidence: 99%

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Shock consolidation response of CeO2 powders

Fredenburg¹,

Dennis-Koller²,

Dattelbaum³

2012

AIP Conference Proceedings

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“…Recent ab initio theoretical calculations have predicted a phase transition from the pyrite-to the cotunnite (α-PbCl 2 )-type structure around 700 GPa accompanied with further increase in CoN to 9 (11,12). Although these studies showed some new aspects of SiO 2 at the pressures where experiments of solid-solid phase change are nearly impossible, they adopted the cotunnite structure to SiO 2 simply based on the knowledge of high-pressure behaviors of some analog compounds (13)(14)(15)(16) with no attention to other candidates.…”

mentioning

confidence: 99%

Prediction of a hexagonal SiO ₂ phase affecting stabilities of MgSiO ₃ and CaSiO ₃ at multimegabar pressures

Tsuchiya

2011

Proc. Natl. Acad. Sci. U.S.A.

121

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Ultrahigh-pressure phase relationship of SiO 2 silica in multimegabar pressure condition is still quite unclear. Here, we report a theoretical prediction on a previously uncharacterized stable structure of silica with an unexpected hexagonal Fe 2 P-type form. This phase, more stable than the cotunnite-type structure, a previously postulated postpyrite phase, was discovered to stabilize at 640 GPa through a careful structure search by means of ab initio density functional computations over various structure models. This is the first evidential result of the pressure-induced phase transition to the Fe 2 P-type structure among all dioxide compounds. The crystal structure consists of closely packed, fairly regular SiO 9 tricapped trigonal prisms with a significantly compact lattice. Additional investigation further elucidates large effects of this phase change in SiO 2 on the stability of MgSiO 3 and CaSiO 3 at multimegabar pressures. A postperovskite phase of MgSiO 3 breaks down at 1.04 TPa along an assumed adiabat of super-Earths and yields Fe 2 P-type SiO 2 and CsCl (B2)-type MgO. CaSiO 3 perovskite, on the other hand, directly dissociates into SiO 2 and metallic CaO, skipping a postperovskite polymorph. Predicted ultrahigh-pressure and temperature phase diagrams of SiO 2 , MgSiO 3 , and CaSiO 3 indicate that the Fe 2 P-type SiO 2 could be one of the dominant components in the deep mantles of terrestrial exoplanets and the cores of gas giants.ab initio density functional simulation | multimegabar crystalline phase | silicon dioxide | super-Earth mantle E xploration of new high-pressure phases of silica has always attracted substantial interests in geophysics, materials science, and condensed matter physics because of its broad fundamental applicability (1-10). Low-pressure polymorphs of silica such as quartz have Si tetrahedrally coordinated by O, whereas in stishovite-(a rutile-type SiO 2 phase), CaCl 2 -, α-PbO 2 -, and pyrite (FeS 2 )-type phases, which form subsequently from ∼10 to ∼250 GPa, the coordination number (CoN) of Si increases to 6. Recent ab initio theoretical calculations have predicted a phase transition from the pyrite-to the cotunnite (α-PbCl 2 )-type structure around 700 GPa accompanied with further increase in CoN to 9 (11, 12). Although these studies showed some new aspects of SiO 2 at the pressures where experiments of solid-solid phase change are nearly impossible, they adopted the cotunnite structure to SiO 2 simply based on the knowledge of high-pressure behaviors of some analog compounds (13-16) with no attention to other candidates.Recent improvements in detection methods allow for the discovery of low-mass terrestrial exoplanets with 1-10 times Earth's mass (M ⊕ ), so-called "super-Earths" (17-20). Because pressure conditions of their deep mantles, as well as those of the cores of some gas giants, are located in a sub-terapascal range (21, 22), ultrahigh-pressure and temperature stabilities of SiO 2 and some other silicates such as MgSiO 3 and CaSiO 3 , major components in the Earth's...

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High-pressure x-ray diffraction study ofCeO2to 70 GPa and pressure-induced phase transformation from the fluorite structure

Cited by 185 publications

References 19 publications

New high-pressure phase and equation of state of Ce2Zr2O8

New high-pressure phase and equation of state of Ce2Zr2O8

Shock consolidation response of CeO2 powders

Prediction of a hexagonal SiO ₂ phase affecting stabilities of MgSiO ₃ and CaSiO ₃ at multimegabar pressures

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High-pressure x-ray diffraction study ofCeO2to 70 GPa and pressure-induced phase transformation from the fluorite structure

Cited by 185 publications

References 19 publications

New high-pressure phase and equation of state of Ce2Zr2O8

New high-pressure phase and equation of state of Ce2Zr2O8

Shock consolidation response of CeO2 powders

Prediction of a hexagonal SiO 2 phase affecting stabilities of MgSiO 3 and CaSiO 3 at multimegabar pressures

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Product

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Prediction of a hexagonal SiO ₂ phase affecting stabilities of MgSiO ₃ and CaSiO ₃ at multimegabar pressures