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Title: Synthesis and equation of state of perovskite in the (Mg,Fe)[subscript 3]Al[subscript 2]Si[subscript 3]O[subscript 12] system to 177 GPa

Authors:
; ; ; ;  [1];  [2];  [2];  [2]
  1. (Princeton)
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
DOE - BASIC ENERGY SCIENCESNSF
OSTI Identifier:
1130590
Resource Type:
Journal Article
Resource Relation:
Journal Name: Earth Planet. Sci. Lett.; Journal Volume: 357-358; Journal Issue: 12, 2012
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Dorfman, Susannah M., Shieh, Sean R., Meng, Yue, Prakapenka, Vitali B., Duffy, Thomas S., CIW), UC), and UWO). Synthesis and equation of state of perovskite in the (Mg,Fe)[subscript 3]Al[subscript 2]Si[subscript 3]O[subscript 12] system to 177 GPa. United States: N. p., 2016. Web. doi:10.1016/j.epsl.2012.09.024.
Dorfman, Susannah M., Shieh, Sean R., Meng, Yue, Prakapenka, Vitali B., Duffy, Thomas S., CIW), UC), & UWO). Synthesis and equation of state of perovskite in the (Mg,Fe)[subscript 3]Al[subscript 2]Si[subscript 3]O[subscript 12] system to 177 GPa. United States. doi:10.1016/j.epsl.2012.09.024.
Dorfman, Susannah M., Shieh, Sean R., Meng, Yue, Prakapenka, Vitali B., Duffy, Thomas S., CIW), UC), and UWO). 2016. "Synthesis and equation of state of perovskite in the (Mg,Fe)[subscript 3]Al[subscript 2]Si[subscript 3]O[subscript 12] system to 177 GPa". United States. doi:10.1016/j.epsl.2012.09.024.
@article{osti_1130590,
title = {Synthesis and equation of state of perovskite in the (Mg,Fe)[subscript 3]Al[subscript 2]Si[subscript 3]O[subscript 12] system to 177 GPa},
author = {Dorfman, Susannah M. and Shieh, Sean R. and Meng, Yue and Prakapenka, Vitali B. and Duffy, Thomas S. and CIW) and UC) and UWO)},
abstractNote = {},
doi = {10.1016/j.epsl.2012.09.024},
journal = {Earth Planet. Sci. Lett.},
number = 12, 2012,
volume = 357-358,
place = {United States},
year = 2016,
month = 7
}
  • The formation and properties of the post-perovskite (CaIrO{sub 3}-type) phase were studied in Fe-rich compositions along the pyrope-almandine ((Mg,Fe){sub 3}Al{sub 2}Si{sub 3}O{sub 12}) join. Natural and synthetic garnet starting materials with almandine fractions from 38 to 90 mol% were studied using synchrotron X-ray diffraction in the laser-heated diamond anvil cell. Single-phase post-perovskite could be successfully synthesized from garnet compositions at pressures above 148 GPa and temperatures higher than 1600 K. In some cases, evidence for a minor amount of Al{sub 2}O{sub 3} post-perovskite was observed for Alm38 and Alm54 compositions in the perovskite + post-perovskite two-phase region. Pressure-volume data formore » the post-perovskite phases collected during decompression show that incorporation of Fe leads to a systematic increase of unit cell volume broadly similar to the variation observed in the (Mg,Fe)SiO{sub 3} system. The presence of Al{sub 2}O{sub 3} increases the stability of perovskite relative to post-perovskite, requiring higher pressures (> 148 GPa) for synthesis of pure post-perovskites. Our data together with those of Tateno et al. (2005) also suggest that in the Al-rich system the presence of Fe has no strong effect on the pressure required to synthesize the pure post-perovskite phase, but the two-phase perovskite and post-perovskite region may be broad and its width dependent on Fe content. Our results suggest that any regions highly enriched in Al{sub 2}O{sub 3} may consist of either the perovskite phase or a mixture of perovskite and post-perovskite phases throughout the entire thickness of the D* region. The observed synthesis pressures (> 148 GPa) for a pure post-perovskite phase are beyond that at the Earth's core-mantle boundary ({approx} 135 GPa).« less
  • The change of crystal structure in yttrium iron garnet Y{sub 3}Fe{sub 5}O{sub 12} was studied at room temperature at high pressures up to {approx}55 GPa by the x-ray diffraction technique in diamond anvil cells. At a pressure of about {approx}50 GPa, a drastic change in the x-ray diffraction pattern was observed indicating the transition into an amorphouslike state. When the pressure was increased, the bulk modulus of YIG was found to be 193 {+-} 4 GPa. It was also found that the amorphous state was retained after decompression down to ambient pressure. From the shape of x-ray patterns in themore » 'amorphous' phase, it was concluded that the local atomic structure consists of iron-oxygen FeO{sub 6} octahedral complexes with disordered orientations of local axis and of randomly arranged others ion fragments with the overall Y{sub 3}Fe{sub 5}O{sub 12} composition. For the amorphous phase, it was evaluated that the bulk modulus of FeO{sub 6} octahedral complexes is about 260 GPa.« less
  • In this paper we report a new high-pressure rhombohedral phase of Ce{sub 2}Zr{sub 2}O{sub 8} observed in high-pressure angle-dispersive x-ray diffraction and Raman spectroscopy studies up to nearly 12 GPa. The ambient-pressure cubic phase of Ce{sub 2}Zr{sub 2}O{sub 8} transforms to a rhombohedral structure beyond 5 GPa with a feeble distortion in the lattice. The pressure evolution of the unit-cell volume showed a change in compressibility above 5 GPa. The unit-cell parameters of the high-pressure rhombohedral phase at 12.1 GPa are a{sub h} = 14.6791(3) {angstrom}, c{sub h} = 17.9421(5) {angstrom}, and V = 3348.1(1) {angstrom}{sup 3}. The structure relationsmore » between the parent cubic (P2{sub 1}3) and rhombohedral (P3{sub 2}) phases were obtained via group-subgroup relations. All the Raman modes of the cubic phase showed linear evolution with pressure, with the hardest one at 197 cm{sup -1}. Some Raman modes of the high-pressure phase have a non-linear evolution with pressure, and softening of one low-frequency mode with pressure is found. The compressibility, equation of state, and pressure coefficients of Raman modes of Ce{sub 2}Zr{sub 2}O{sub 8} are also reported.« less