scholarly journals X-ray diffraction and Raman studies of beryllium: Static and elastic properties at high pressures

2005 ◽  
Vol 72 (9) ◽  
Author(s):  
W. J. Evans ◽  
M. J. Lipp ◽  
H. Cynn ◽  
C. S. Yoo ◽  
M. Somayazulu ◽  
...  
Keyword(s):  
Elastic Properties ◽  
High Pressures ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Thermostructural and Elastic Properties of PbTe and Pb0.884Cd0.116Te: A Combined Low-Temperature and High-Pressure X-ray Diffraction Study of Cd-Substitution Effects

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1063 ◽  
Author(s):  
Roman Minikayev ◽  
Fatemeh Safari ◽  
Andrzej Katrusiak ◽  
Wojciech Szuszkiewicz ◽  
Andrzej Szczerbakow ◽  
...  
Keyword(s):  
Elastic Properties ◽  
High Pressures ◽  
Lattice Parameter ◽  
Unit Cell ◽  
Substitution Effects ◽  
X Ray Diffraction ◽  
Stability Range ◽  
X Ray ◽  
Atomic Displacements ◽  
Unit Cell Size

Rocksalt-type (Pb,Cd)Te belongs to IV–VI semiconductors exhibiting thermoelectric properties. With the aim of understanding of the influence of Cd substitution in PbTe on thermostructural and elastic properties, we studied PbTe and Pb0.884Cd0.116Te (i) at low temperatures (15 to 300 K) and (ii) at high pressures within the stability range of NaCl-type PbTe (up to 4.5 GPa). For crystal structure studies, powder and single crystal X-ray diffraction methods were used. Modeling of the data included the second-order Grüneisen approximation of the unit-cell-volume variation, V(T), the Debye expression describing the mean square atomic displacements (MSDs), <u2>(T), and Birch–Murnaghan equation of state (BMEOS). The fitting of the temperature-dependent diffraction data provided model variations of lattice parameter, the thermal expansion coefficient, and MSDs with temperature. A comparison of the MSD runs simulated for the PbTe and mixed (Pb,Cd)Te crystal leads to the confirmation of recent findings that the cation displacements are little affected by Cd substitution at the Pb site; whereas the Te displacements are markedly higher for the mixed crystal. Moreover, information about static disorder caused by Cd substitution is obtained. The calculations provided two independent ways to determine the values of the overall Debye temperature, θD. The resulting values differ only marginally, by no more than 1 K for PbTe and 7 K for Pb0.884Cd0.116Te crystals. The θD values for the cationic and anionic sublattices were determined. The Grüneisen parameter is found to be nearly independent of temperature. The variations of unit-cell size with rising pressure (the NaCl structure of Pb0.884Cd0.116Te sample was conserved), modeled with the BMEOS, provided the dependencies of the bulk modulus, K, on pressure for both crystals. The K0 value is 45.6(2.5) GPa for PbTe, whereas that for Pb0.884Cd0.116Te is significantly reduced, 33.5(2.8) GPa, showing that the lattice with fractional Cd substitution is less stiff than that of pure PbTe. The obtained experimental values of θD and K0 for Pb0.884Cd0.116Te are in line with the trends described in recently reported theoretical study for (Pb,Cd)Te mixed crystals.

scholarly journals Curvature Elastic Properties of Phosphatidylethanolamines with Mono-and Polyunsaturated Hydrocarbon Chains - An NMR and X-Ray Diffraction Study

2012 ◽  
Vol 102 (3) ◽  
pp. 413a
Author(s):  
Walter E. Teague ◽  
Olivier Soubias ◽  
Nola L. Fuller ◽  
R. Peter Rand ◽  
Klaus Gawrisch
Keyword(s):  
Diffraction Study ◽  
Elastic Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrocarbon Chains

Monoclinic FeO at high pressures

2008 ◽  
Vol 223 (7/2008) ◽  
Author(s):  
Innokenty Kantor ◽  
Alexander Kurnosov ◽  
Catherine McCammon ◽  
Leonid Dubrovinsky
Keyword(s):  
High Pressure ◽  
Iron Oxide ◽  
Single Crystal ◽  
Diffraction Study ◽  
High Pressures ◽  
X Ray Diffraction ◽  
X Ray

AbstractA high-pressure quasi-single crystal X-ray diffraction study of a synthetic iron oxide Fe

X-ray diffraction and Raman studies of the CuGeO3(III)–(IV) transformation under high pressures

2005 ◽  
Vol 61 (10) ◽  
pp. 2418-2422 ◽  
Author(s):  
Li Chung Ming ◽  
Shiv K. Sharma ◽  
A.J. Jayaraman ◽  
Y. Kobayashi ◽  
E. Suzuki ◽  
...  
Keyword(s):  
High Pressures ◽  
X Ray Diffraction ◽  
X Ray

Erratum: X-ray diffraction studies and thermal and elastic properties of2H-TaSe2

1981 ◽  
Vol 24 (2) ◽  
pp. 1155-1155 ◽  
Author(s):  
J. L. Feldman ◽  
C. L. Vold ◽  
E. F. Skelton ◽  
S. C. Yu ◽  
I. L. Spain
Keyword(s):  
Elastic Properties ◽  
X Ray Diffraction ◽  
X Ray

Dehydration and decomposition of pyrophyllite at high pressures: electrical conductivity and X-ray diffraction studies to 5 GPa

1997 ◽  
Vol 34 (6) ◽  
pp. 875-882 ◽  
Author(s):  
Tara L. Hicks ◽  
Richard A. Secco
Keyword(s):  
Electrical Conductivity ◽  
South African ◽  
Pressure Dependence ◽  
High Pressures ◽  
Ionic Conduction ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Dependence Of Conductivity

The dehydration and decomposition of South African pyrophyllite were studied in the pressure range 2.5–5.0 GPa and in the temperature (T) range 295–1473 K using both in situ electrical conductivity measurements and X-ray diffraction studies on the recovered samples. Activation energies for conduction (Qc) vary in the range 0.02–0.07 eV for T ≤ 500 K where the dominant conduction mode is electronic, and Qc is in the range 1.10–1.28 eV for T ≥ 500 K where ionic conduction dominates. Abrupt changes in the isobaric temperature dependence of conductivity mark the onset of dehydration and subsequent decomposition into kyanite plus quartz–coesite. At 2.5 GPa, South African pyrophyllite forms the dehydroxylate phase at 760 K with a pressure dependence of ~30 K/GPa and complete decomposition follows at 1080 K with a pressure dependence of ~41 K/GPa. The resulting pressure–temperature phase diagram is in very good agreement with many previous studies at 1 atm (101.325 kPa).

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