scholarly journals Investigation of Ultrahigh-Pressure Phase Transitions in Metals with a Toroidal Diamond Anvil Cell

2019 ◽  
Author(s):  
Z Jenei
Keyword(s):  
Phase Transitions ◽  
Diamond Anvil Cell ◽  
Ultrahigh Pressure ◽  
Diamond Anvil ◽  
Pressure Phase

scholarly journals Phase transitions beyond post-perovskite in NaMgF3 to 160 GPa

2019 ◽  
Vol 116 (39) ◽  
pp. 19324-19329 ◽  
Author(s):  
Rajkrishna Dutta ◽  
Eran Greenberg ◽  
Vitali B. Prakapenka ◽  
Thomas S. Duffy
Keyword(s):  
Phase Transitions ◽  
Diamond Anvil Cell ◽  
Extrasolar Planets ◽  
High Pressures ◽  
Model System ◽  
Similar Sequence ◽  
Deep Interior ◽  
Diamond Anvil ◽  
Binary Compounds ◽  
Pressure Phase

Neighborite, NaMgF3, is used as a model system for understanding phase transitions in ABX3 systems (e.g., MgSiO3) at high pressures. Here we report diamond anvil cell experiments that identify the following phases in NaMgF3 with compression to 162 GPa: NaMgF3 (perovskite) → NaMgF3 (post-perovskite) → NaMgF3 (Sb2S3-type) → NaF (B2-type) + NaMg2F5 (P21/c) → NaF (B2) + MgF2 (cotunnite-type). Our results demonstrate the existence of an Sb2S3-type post-post-perovskite ABX3 phase. We also experimentally demonstrate the formation of the P21/c AB2X5 phase which has been proposed theoretically to be a common high-pressure phase in ABX3 systems. Our study provides an experimental observation of the full sequence of phase transitions from perovskite to post-perovskite to post-post-perovskite followed by 2-stage breakdown to binary compounds. Notably, a similar sequence of transitions is predicted to occur in MgSiO3 at ultrahigh pressures, where it has implications for the mineralogy and dynamics in the deep interior of large, rocky extrasolar planets.

scholarly journals High-Pressure Phase Diagrams of Na2CO3 and K2CO3

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 599
Author(s):  
Pavel N. Gavryushkin ◽  
Altyna Bekhtenova ◽  
Sergey S. Lobanov ◽  
Anton Shatskiy ◽  
Anna Yu. Likhacheva ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Phase Diagrams ◽  
Diffraction Pattern ◽  
Diamond Anvil Cell ◽  
Stability Field ◽  
Maximum Pressure ◽  
Diamond Anvil ◽  
Diffraction Peaks ◽  
New Phase ◽  
Pressure Phase

The phase diagrams of Na 2 CO 3 and K 2 CO 3 have been determined with multianvil (MA) and diamond anvil cell (DAC) techniques. In MA experiments with heating, γ -Na 2 CO 3 is stable up to 12 GPa and above this pressure transforms to P 6 3 /mcm-phase. At 26 GPa, Na 2 CO 3 - P 6 3 /mcm transforms to the new phase with a diffraction pattern similar to that of the theoretically predicted Na 2 CO 3 - P 2 1 /m. On cold compression in DAC experiments, γ -Na 2 CO 3 is stable up to the maximum pressure reached of 25 GPa. K 2 CO 3 shows a more complex sequence of phase transitions. Unlike γ Na 2 CO 3 , γ -K 2 CO 3 has a narrow stability field. At 3 GPa, K 2 CO 3 presents in the form of the new phase, called K 2 CO 3 -III, which transforms into another new phase, K 2 CO 3 -IV, above 9 GPa. In the pressure range of 9–15 GPa, another new phase or the mixture of phases III and IV is observed. The diffraction pattern of K 2 CO 3 -IV has similarities with that of the theoretically predicted K 2 CO 3 - P 2 1 /m and most of the diffraction peaks can be indexed with this structure. Water has a dramatic effect on the phase transitions of K 2 CO 3 . Reconstruction of the diffraction pattern of γ -K 2 CO 3 is observed at pressures of 0.5–3.1 GPa if the DAC is loaded on the air.

Observation of pressure-induced electron transfer in SnC2O4

2021 ◽  
Author(s):  
Michael Pravica ◽  
Roman Chernikov ◽  
Kevin Ayala Pineda ◽  
Jianbao Zhao ◽  
Petrika Cifligu ◽  
...  
Keyword(s):  
High Pressure ◽  
Electron Transfer ◽  
Phase Transitions ◽  
Absorption Spectroscopy ◽  
Diamond Anvil Cell ◽  
X Ray ◽  
Pressure Behavior ◽  
Diamond Anvil ◽  
X Ray Absorption

We examined the high pressure behavior of stannous oxalate via Raman and x-ray absorption spectroscopy (XAS) inside a diamond anvil cell. Phase transitions were observed to occur near 2.6 and...

Pressure-induced phase transitions of β-type pyrochlore CsTaWO6

RSC Advances ◽  
2016 ◽  
Vol 6 (97) ◽  
pp. 94287-94293 ◽  
Author(s):  
F. X. Zhang ◽  
C. L. Tracy ◽  
J. Shamblin ◽  
R. I. Palomares ◽  
M. Lang ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Raman Scattering ◽  
Diamond Anvil Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diamond Anvil

The β-type pyrochlore CsTaWO6 was studied by synchrotron X-ray diffraction (XRD) and Raman scattering methods up to pressures of 43 GPa using a diamond anvil cell (DAC).

Phase transitions in crystalline sulfur at p>8 GPa, observed by Raman spectroscopy in a diamond anvil cell

1990 ◽  
Vol 6 (1) ◽  
pp. 57-75 ◽  
Author(s):  
W. Häfner ◽  
J. Kritzenberger ◽  
H. Olijnyk ◽  
A. Wokaun
Keyword(s):  
Raman Spectroscopy ◽  
Phase Transitions ◽  
Diamond Anvil Cell ◽  
Diamond Anvil
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