Elastic Constants of Ammonium Bromide. II. High‐Pressure Ultrasonic Investigation of the Phase Transitions

1968 ◽  
Vol 49 (12) ◽  
pp. 5282-5293 ◽  
Author(s):  
Carl W. Garland ◽  
Robert A. Young
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Elastic Constants ◽  
Ammonium Bromide ◽  
Ultrasonic Investigation

scholarly journals High-Pressure Spectroscopy Study of Zn(IO3)2 Using Far-Infrared Synchrotron Radiation

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 34
Author(s):  
Akun Liang ◽  
Robin Turnbull ◽  
Enrico Bandiello ◽  
Ibraheem Yousef ◽  
Catalin Popescu ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Synchrotron Radiation ◽  
Infrared Radiation ◽  
Room Temperature ◽  
Far Infrared ◽  
Low Pressure ◽  
Pressure Response ◽  
Spectroscopy Study ◽  
Far Infrared Radiation

We report the first high-pressure spectroscopy study on Zn(IO3)2 using synchrotron far-infrared radiation. Spectroscopy was conducted up to pressures of 17 GPa at room temperature. Twenty-five phonons were identified below 600 cm−1 for the initial monoclinic low-pressure polymorph of Zn(IO3)2. The pressure response of the modes with wavenumbers above 150 cm−1 has been characterized, with modes exhibiting non-linear responses and frequency discontinuities that have been proposed to be related to the existence of phase transitions. Analysis of the high-pressure spectra acquired on compression indicates that Zn(IO3)2 undergoes subtle phase transitions around 3 and 8 GPa, followed by a more drastic transition around 13 GPa.

High-pressure phase transitions in AlSb

2001 ◽  
Vol 62 (5) ◽  
pp. 941-949 ◽  
Author(s):  
H. Hirano ◽  
S. Uehara ◽  
A. Mori ◽  
A. Onodera ◽  
K. Takemura ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
High Pressure Phase ◽  
Pressure Phase

The Inductive Coil Technique for High-Pressure Measurements: An Analysis of Nonhomogeneous Material Environment as a Source of Irreproducibility and Error

1967 ◽  
Vol 89 (3) ◽  
pp. 554-560 ◽  
Author(s):  
A. A. Giardini
Keyword(s):  
High Pressure ◽  
Internal Pressure ◽  
Elastic Constants ◽  
Graphical Form ◽  
Pressure Measurements ◽  
Pressure Data ◽  
Nonhomogeneous Material ◽  
Resistivity Measurements ◽  
Material Environment ◽  
Critical Yield

Significant sources of error independent of the apparatus are analyzed on the basis of experimental experience and elastic theory. All are mechanical in nature and subject to corrective action. The most serious is found to be self-generating internal pressure differences which result from differential elastic and dimensional values in multicomponent assemblies. High-pressure data on elastic constants, relative critical yield stresses, radial displacements, and ratios of external to internal pressure for various compositional arrangements of pyrophyllite, MgO, NaCl, and AgCl are given in graphical form. Observance of suggested corrective measures can render the inductive coil technique capable of operational accuracies of 2 percent or better in compressibility and resistivity measurements.

Phase Transitions of Nematic Main-Chain Polyesters Under High Pressure

1988 ◽  
Vol 155 (1) ◽  
pp. 521-529 ◽  
Author(s):  
V. N. Raja ◽  
R. Shashidhar ◽  
S. Chandrasekhar ◽  
A. Blumstein ◽  
R. B. Blumstein ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Main Chain

Hydrostatic Deformation Potentials and Phase Transitions in CuGa(SxSe1−x)2 Alloys at High Pressure

1995 ◽  
Vol 187 (1) ◽  
pp. 149-156 ◽  
Author(s):  
J. González ◽  
E. Calderón ◽  
F. Capet
Keyword(s):  
High Pressure ◽  
Phase Transitions

Crystal structure, compressibility and possible phase transitions in \boldvarepsilon-FeSi studied by first-principles pseudopotential calculations

1999 ◽  
Vol 55 (4) ◽  
pp. 484-493 ◽  
Author(s):  
Lidunka Vočadlo ◽  
Geoffrey D. Price ◽  
I. G. Wood
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Phase Transitions ◽  
First Principles ◽  
Stable Phase ◽  
Third Order ◽  
First Derivative ◽  
Pseudopotential Calculations ◽  
Cscl Type ◽  
Murnaghan Equation

An investigation of the relative stability of the FeSi structure and of some hypothetical polymorphs of FeSi has been made by first-principles pseudopotential calculations. It has been shown that the observed distortion from ideal sevenfold coordination is essential in stabilizing the FeSi structure relative to one of the CsCl type. Application of high pressure to FeSi is predicted to produce a structure having nearly perfect sevenfold coordination. However, it appears that FeSi having a CsCl-type structure will be the thermodynamically most stable phase for pressures greater than 13 GPa. Fitting of the calculated internal energy vs volume for the FeSi structure to a third-order Birch–Murnaghan equation of state led to values, at T = 0 K, for the bulk modulus, K 0, and for its first derivative with respect to pressure, K 0′, of 227 GPa and 3.9, respectively.

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