3-D convection studies on the thermal state in the lower mantle with post-perovskite phase transition

2006 ◽  
Vol 33 (12) ◽  
Author(s):  
Masanori Kameyama ◽  
David A. Yuen
Keyword(s):  
Phase Transition ◽  
Lower Mantle ◽  
Thermal State ◽  
Perovskite Phase

scholarly journals In situ measurements of the majorite-akimotoite-perovskite phase transition boundaries in MgSiO3

2001 ◽  
Vol 28 (23) ◽  
pp. 4351-4354 ◽  
Author(s):  
Kei Hirose ◽  
Tetsuya Komabayashi ◽  
Motohiko Murakami ◽  
Ken-ichi Funakoshi
Keyword(s):  
Phase Transition ◽  
Perovskite Phase ◽  
In Situ Measurements

Stabilization of perovskite phase and dielectric properties of Pb(Zn, Mg)1/3Nb2/3O3-PbTiO3 ceramics prepared by excess constituent oxides

1994 ◽  
Vol 9 (10) ◽  
pp. 2634-2644 ◽  
Author(s):  
Hyun M. Jang ◽  
Kyu-Mann Lee ◽  
Moon-Ho Lee
Keyword(s):  
Phase Transition ◽  
Diffuse Phase Transition ◽  
Short Range ◽  
Perovskite Phase ◽  
Complex Impedance ◽  
Pyrochlore Phase ◽  
Charge Carriers ◽  
Pbtio3 Ceramics ◽  
Additional Formation ◽  
Diffuse Phase

The perovskite phase in PZN-PMN-PT (PbZn1/3Nb2/3O3-PbMg1/3Nb2/3O3-PbTiO3) pseudoternary ceramics was stabilized by the addition of excess constituent divalent oxides (PbO, MgO, and ZnO). 5 mol% excess MgO or 7.5 mol% excess PbO was sufficient to eliminate the remnant cubic pyrochlore phase after sintering at 1100 °C for 1 h. The enhanced diffuse phase transition (DPT) and the decrease in the electrical resistivity were observed in the presence of excess ZnO or MgO. These were interpreted in terms of the additional formation of negatively charged, short-range ordered 1: 1 domains with a concomitant generation of charge carriers (holes). The behavior of excess MgO or ZnO at concentrations above 5 mol% was studied by examining complex impedance patterns.

Lattice reconstruction of La-incorporated CsPbI2Br with suppressed phase transition for air-processed all-inorganic perovskite solar cells

2020 ◽  
Vol 8 (10) ◽  
pp. 3351-3358 ◽  
Author(s):  
Shoulong Chen ◽  
Tianju Zhang ◽  
Xiaolin Liu ◽  
Jinli Qiao ◽  
Lin Peng ◽  
...  
Keyword(s):  
Phase Transition ◽  
Solar Cells ◽  
Perovskite Phase ◽  
Perovskite Solar Cells ◽  
Inorganic Perovskite

A stable CsPbI2Br perovskite phase can be achieved when doped with an appropriate amount of La3+ ions.

scholarly journals Velocity and density characteristics of subducted oceanic crust and the origin of lower-mantle heterogeneities

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Wenzhong Wang ◽  
Yinhan Xu ◽  
Daoyuan Sun ◽  
Sidao Ni ◽  
Renata Wentzcovitch ◽  
...  
Keyword(s):  
Phase Transition ◽  
Oceanic Crust ◽  
Seismic Tomography ◽  
Lower Mantle ◽  
Shear Velocity ◽  
Calcium Ferrite ◽  
Velocity Anomaly ◽  
Mantle Heterogeneities ◽  
Subducted Oceanic Crust ◽  
Low Shear

AbstractSeismic heterogeneities detected in the lower mantle were proposed to be related to subducted oceanic crust. However, the velocity and density of subducted oceanic crust at lower-mantle conditions remain unknown. Here, we report ab initio results for the elastic properties of calcium ferrite‐type phases and determine the velocities and density of oceanic crust along different mantle geotherms. We find that the subducted oceanic crust shows a large negative shear velocity anomaly at the phase boundary between stishovite and CaCl2-type silica, which is highly consistent with the feature of mid-mantle scatterers. After this phase transition in silica, subducted oceanic crust will be visible as high-velocity heterogeneities as imaged by seismic tomography. This study suggests that the presence of subducted oceanic crust could provide good explanations for some lower-mantle seismic heterogeneities with different length scales except large low shear velocity provinces (LLSVPs).

Perovskite in Earth’s deep interior

Science ◽  
2017 ◽  
Vol 358 (6364) ◽  
pp. 734-738 ◽  
Author(s):  
Kei Hirose ◽  
Ryosuke Sinmyo ◽  
John Hernlund
Keyword(s):  
Phase Transition ◽  
Trace Elements ◽  
Transport Properties ◽  
Lower Mantle ◽  
Dynamic Evolution ◽  
Deep Interior ◽  
Rocky Planets ◽  
The Universe ◽  
Perovskite Type ◽  
Important Constituent

Silicate perovskite-type phases are the most abundant constituent inside our planet and are the predominant minerals in Earth’s lower mantle more than 660 kilometers below the surface. Magnesium-rich perovskite is a major lower mantle phase and undergoes a phase transition to post-perovskite near the bottom of the mantle. Calcium-rich perovskite is proportionally minor but may host numerous trace elements that record chemical differentiation events. The properties of mantle perovskites are the key to understanding the dynamic evolution of Earth, as they strongly influence the transport properties of lower mantle rocks. Perovskites are expected to be an important constituent of rocky planets larger than Mars and thus play a major role in modulating the evolution of terrestrial planets throughout the universe.

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