Equation of State and Possible Critical Phase Transitions in MgSiO3 Perovskite at Lower-Mantle Conditions

1988 ◽  
pp. 91-112 ◽  
Author(s):  
Mark S. T. Bukowinski ◽  
George H. Wolf
Keyword(s):  
Phase Transitions ◽  
Equation Of State ◽  
Lower Mantle ◽  
Mgsio3 Perovskite ◽  
Critical Phase

Equation of state of lower mantle (Al,Fe)-MgSiO3 perovskite

2001 ◽  
Vol 193 (3-4) ◽  
pp. 501-508 ◽  
Author(s):  
Denis Andrault ◽  
Nathalie Bolfan-Casanova ◽  
Nicolas Guignot
Keyword(s):  
Equation Of State ◽  
Lower Mantle ◽  
Mgsio3 Perovskite

Various types of holographic metal/superconductor phase transitions with dark matter sector

2016 ◽  
Vol 26 (06) ◽  
pp. 1750046
Author(s):  
Yan Peng ◽  
Tao Chen ◽  
Guohua Liu ◽  
Pengwei Ma
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Dark Matter ◽  
Phase Transitions ◽  
Transition Temperature ◽  
De Sitter ◽  
Holographic Superconductor ◽  
Black Hole Background ◽  
Critical Phase ◽  
Matter Sector

We generalize the holographic superconductor model with dark matter sector by including the Stückelberg mechanism in the four-dimensional anti-de Sitter (AdS) black hole background away from the probe limit. We study effects of the dark matter sector on the [Formula: see text]-wave scalar condensation and find that the dark matter sector affects the critical phase transition temperature and also the order of phase transitions. At last, we conclude that the dark matter sector brings richer physics in this general metal/superconductor system.

scholarly journals Isothermal equation of state and high-pressure phase transitions of synthetic meridianiite (MgSO4·11D2O) determined by neutron powder diffraction and quasielastic neutron spectroscopy

2017 ◽  
Vol 73 (1) ◽  
pp. 33-46 ◽  
Author(s):  
A. Dominic Fortes ◽  
Felix Fernandez-Alonso ◽  
Matthew Tucker ◽  
Ian G. Wood
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Equation Of State ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Neutron Powder Diffraction ◽  
Bulk Liquid ◽  
Icy Satellites ◽  
Neutron Spallation Source ◽  
Quasielastic Neutron

We have collected neutron powder diffraction data from MgSO4·11D2O (the deuterated analogue of meridianiite), a highly hydrated sulfate salt that is thought to be a candidate rock-forming mineral in some icy satellites of the outer solar system. Our measurements, made using the PEARL/HiPr and OSIRIS instruments at the ISIS neutron spallation source, covered the range 0.1 < P < 800 MPa and 150 < T < 280 K. The refined unit-cell volumes as a function of P and T are parameterized in the form of a Murnaghan integrated linear equation of state having a zero-pressure volume V 0 = 706.23 (8) Å3, zero-pressure bulk modulus K 0 = 19.9 (4) GPa and its first pressure derivative, K′ = 9 (1). The structure's compressibility is highly anisotropic, as expected, with the three principal directions of the unit-strain tensor having compressibilities of 9.6 × 10−3, 3.4 × 10−2 and 3.4 × 10−3 GPa−1, the most compressible direction being perpendicular to the long axis of a discrete hexadecameric water cluster, (D2O)16. At high pressure we observed two different phase transitions. First, warming of MgSO4·11D2O at 545 MPa resulted in a change in the diffraction pattern at 275 K consistent with partial (peritectic) melting; quasielastic neutron spectra collected simultaneously evince the onset of the reorientational motion of D2O molecules with characteristic time-scales of 20–30 ps, longer than those found in bulk liquid water at the same temperature and commensurate with the lifetime of solvent-separated ion pairs in aqueous MgSO4. Second, at ∼ 0.9 GPa, 240 K, MgSO4·11D2O decomposed into high-pressure water ice phase VI and MgSO4·9D2O, a recently discovered phase that has hitherto only been formed at ambient pressure by quenching small droplets of MgSO4(aq) in liquid nitrogen. The fate of the high-pressure enneahydrate on further compression and warming is not clear from the neutron diffraction data, but its occurrence indicates that it may also be a rock-forming mineral in the deep mantles of large icy satellites.

Computation for Equation of States of (Mg0.92, Fe0.08)SiO3 Perovskite Based on Mie-Grüneisen-Debye Model

2014 ◽  
Vol 1046 ◽  
pp. 76-79
Author(s):  
Xiu Fang Chen
Keyword(s):  
High Pressure ◽  
Equation Of State ◽  
Lower Mantle ◽  
Perovskite Structure ◽  
Perovskite Phase ◽  
Debye Model ◽  
Thermal Pressure ◽  
Thermal Equation ◽  
Equation Of States ◽  
Prem Model

In this paper, the thermal equation of state (EOS) of (Mg0.92, Fe0.08)SiO3is computed by Birch-Murnaghan and Mie-Grüneisen-Debye equations and the related parameters are also analyzed. The value of and has little effect on EOS of (Mg0.92, Fe0.08)SiO3perovskite. The effect of EOS of (Mg0.92, Fe0.08)SiO3perovskite is mainly from the temperature under high pressure. The temperature is higher; the deviation of EOS relative to the PREM model is bigger. The thermal EOS complies with PREM model at T=2000K. The thermal pressure of (Mg0.92, Fe0.08)SiO3perovskite a constant only related to temperature at the lower mantle conditions. At the same time, the EOS of (Mg0.92, Fe0.08)SiO3perovskite is insensitive to the data of and at T=2000K, but when and the thermal EOS is more agreement with PREM model. That is to say, when the value of the and is in the range of 253~273 GPa and 3.69~4.23, (Mg0.92, Fe0.08)SiO3is the perovskite phase, and (Mg0.92, Fe0.08)SiO3perovskite structure remains stable at the mantle conditions.

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