Temperature-pressure phase diagram and ferroelectric properties of BaTiO3 single crystal based on a modified Landau potential

2010 ◽  
Vol 108 (11) ◽  
pp. 114105 ◽  
Author(s):  
J. J. Wang ◽  
P. P. Wu ◽  
X. Q. Ma ◽  
L. Q. Chen
Keyword(s):  
Phase Diagram ◽  
Single Crystal ◽  
Ferroelectric Properties ◽  
Pressure Phase ◽  
Landau Potential

High-pressure phase stability and elasticity of ammonia hydrate

2019 ◽  
Vol 104 (9) ◽  
pp. 1307-1314 ◽  
Author(s):  
Xinyang Li ◽  
Weigang Shi ◽  
Xiaodi Liu ◽  
Zhu Mao
Keyword(s):  
Phase Diagram ◽  
High Pressure ◽  
Single Crystal ◽  
Phase Stability ◽  
High Pressures ◽  
Solid Phase ◽  
High Pressure Phase ◽  
Residual Liquid ◽  
Dominant Form ◽  
Pressure Phase

Abstract Phase stability and elasticity of ammonia hydrate have been studied using Raman spectroscopy and Brillion scattering in diamond-anvil cells up to 53 GPa at 300 K. Here we have established the high-pressure phase diagram of ammonia hydrate in three different compositions, including ammonia monohydrate (AMH, NH3·H2O), dihydrate (ADH, NH3·2H2O), and trihydrate (ATH, NH3·3H2O). In contrast to previous experimental results, our Raman and Brillouin measurements at 300 K have shown that all three ammonia hydrates start to dehydrate at 2.1–2.2 GPa. Dehydration of the ammonia hydrate leads to the formation of single-crystal ice-VII and an increase in the concentration of NH3 in the residual liquid. The residual liquid finally turns into solid ammonia hemihydrate phase II (AHH-II) at 4–4.6 GPa, leading to a 28% jump in the compressional-wave velocity (VP). Considering a 10–15 vol% NH3 in the mantle of ice giants, AHH should thus be the dominant form of NH3 coexisting with H2O-ice in the ice giants. Further Brillouin measurements provide crucial constraints on the VP of AHH and the single-crystal elasticity of ice-VII at high pressures and 300 K. VP of AHH increases smoothly with pressure. No anomalous change in VP of AHH was identified up to 39 GPa, although a solid to solid phase transition was noted to occur at ~18 GPa by Raman measurements. In addition, the elasticity of single-crystal ice-VII, which was the dehydration product of ammonia hydrate, has been determined up to 53 GPa at 300 K. The deviation of C12 from C44 observed at 11.4 and 14.6 GPa could be caused by the hydrogen bond symmetrizations or the ordering of dipole of single-crystal ice-VII. An abnormal softening in the elastic moduli C11, C12, and the adiabatic moduli KS together with stiffening in C44 was observed between 42 and 53 GPa, which should be caused by the transition from ice-VII to its pre-transitional state. Of particular interest is the dramatic increase in the anisotropy of ice-VII with increasing pressure. Combining the sound velocity of AHH and ice-VII, we have modeled the VP of ice giants with a volume ratio of 20% AHH and 80% ice-VII in the mantle. The obtained high-pressure phase diagram and elastic properties of ammonia hydrate could contribute to understanding the structure of the mantle in the ice giants and satellites.

High-Pressure Phase Diagram and Equation of State of Solid Helium from Single-Crystal X-Ray Diffraction to 23.3 GPa

1988 ◽  
Vol 60 (25) ◽  
pp. 2649-2652 ◽  
Author(s):  
H. K. Mao ◽  
R. J. Hemley ◽  
Y. Wu ◽  
A. P. Jephcoat ◽  
L. W. Finger ◽  
...  
Keyword(s):  
Phase Diagram ◽  
High Pressure ◽  
Equation Of State ◽  
Single Crystal ◽  
Solid Helium ◽  
High Pressure Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pressure Phase

Epitaxial ferroelectric thin films

1994 ◽  
Vol 52 ◽  
pp. 572-573
Author(s):  
S. G. Ghonge ◽  
E. Goo ◽  
R. Ramesh ◽  
R. Haakenaasen ◽  
D. K. Fork
Keyword(s):  
Single Crystal ◽  
Work Function ◽  
Nonvolatile Memory ◽  
Ferroelectric Properties ◽  
Electrical Contact ◽  
Memory Devices ◽  
Ferroelectric Films ◽  
Si Substrates ◽  
Electro Optic ◽  
Wide Range

Microstructure of epitaxial ferroelectric/conductive oxide heterostructures on LaAIO3(LAO) and Si substrates have been studied by conventional and high resolution transmission electron microscopy. The epitaxial films have a wide range of potential applications in areas such as non-volatile memory devices, electro-optic devices and pyroelectric detectors. For applications such as electro-optic devices the films must be single crystal and for applications such as nonvolatile memory devices and pyroelectric devices single crystal films will enhance the performance of the devices. The ferroelectric films studied are Pb(Zr0.2Ti0.8)O3(PLZT), PbTiO3(PT), BiTiO3(BT) and Pb0.9La0.1(Zr0.2Ti0.8)0.975O3(PLZT).Electrical contact to ferroelectric films is commonly made with metals such as Pt. Metals generally have a large difference in work function compared to the work function of the ferroelectric oxides. This results in a Schottky barrier at the interface and the interfacial space charge is believed to responsible for domain pinning and degradation in the ferroelectric properties resulting in phenomenon such as fatigue.

Temperature-pressure phase diagram of deuterated tetramethylammonium tetrachlorozincate

1984 ◽  
Vol 45 (5) ◽  
pp. 929-938 ◽  
Author(s):  
G. Marion ◽  
R. Almairac ◽  
M. Ribet ◽  
U. Steigenberger ◽  
C. Vettier
Keyword(s):  
Phase Diagram ◽  
Pressure Phase

NEUTRON DIFFRACTION AND MAGNETIZATION STUDY OF THE MAGNETIC PHASE DIAGRAM OF UAs0.75Se0.25 SINGLE CRYSTAL

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-479-C8-480 ◽  
Author(s):  
M. Kuznietz ◽  
P. Burlet ◽  
J. Rossat-Mignod ◽  
O. Vogt ◽  
K. Mattenberger ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Neutron Diffraction ◽  
Single Crystal ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
Magnetization Study

scholarly journals Phase Diagram of Binary Alloy Nanoparticles under High Pressure

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2929
Author(s):  
Han Gyeol Kim ◽  
Joonho Lee ◽  
Guy Makov
Keyword(s):  
Phase Diagram ◽  
Phase Diagrams ◽  
Interaction Parameter ◽  
Excess Volume ◽  
Eutectic Temperature ◽  
Calphad Method ◽  
Alloy Nanoparticles ◽  
Thermodynamic Conditions ◽  
Nanoparticle System ◽  
Pressure Phase

CALPHAD (CALculation of PHAse Diagram) is a useful tool to construct phase diagrams of various materials under different thermodynamic conditions. Researchers have extended the use of the CALPHAD method to nanophase diagrams and pressure phase diagrams. In this study, the phase diagram of an arbitrary A–B nanoparticle system under pressure was investigated. The effects of the interaction parameter and excess volume were investigated with increasing pressure. The eutectic temperature was found to decrease in most cases, except when the interaction parameter in the liquid was zero and that in the solid was positive, while the excess volume parameter of the liquid was positive. Under these conditions, the eutectic temperature increased with increasing pressure.

Temperature–Pressure Phase Diagram for Rb2ZnCl4 Crystals

2015 ◽  
Vol 82 (2) ◽  
pp. 228-233 ◽  
Author(s):  
V. Yu. Kurlyak ◽  
V. Yo. Stadnyk ◽  
V. Stakhura
Keyword(s):  
Phase Diagram ◽  
Pressure Phase

scholarly journals Magnetic Properties and Single Crystal Growth of a Spin Gapped Compound, High Pressure Phase of (VO)2P2O7.

1999 ◽  
Vol 46 (9) ◽  
pp. 1014-1019
Author(s):  
Takashi Saito ◽  
Masaki Azuma ◽  
Mikio Takano ◽  
Zenji Hiroi ◽  
Yasuo Narumi ◽  
...  
Keyword(s):  
High Pressure ◽  
Magnetic Properties ◽  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystal Growth ◽  
High Pressure Phase ◽  
Pressure Phase
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