THERMAL EXPANSION OF SINGLE CRYSTALS OF ZINC AT LOW TEMPERATURES

1965 ◽  
Vol 43 (7) ◽  
pp. 1328-1333 ◽  
Author(s):  
D. A. Channing ◽  
S. Weintroub
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Single Crystals ◽  
Low Temperatures ◽  
Linear Thermal Expansion ◽  
Optical Interference ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Good Agreement

The linear thermal expansion coefficients αψ of two single crystals of Zn of orientations ψ = 10.8° and 63.9 ° with the hexad axis were measured over the temperature range of about 20–270 °K using an absolute Fizeau optical interference technique. The two principal coefficients, [Formula: see text] and [Formula: see text], corresponding to ψ = 0° and 90 ° respectively, were calculated from the Voigt relation, and their values are compared with previously reported experimental data. Above 60 °K there is good agreement with previous work, and below 60 °K the results confirm, in general, the data obtained by McCammon and White. The Grüneisen parameter γ is essentially constant at about 2.1 in the range 100–270 °K, but below 100 °K γ rises appreciably with decreasing temperature and reaches the value of about 3.5 at 20 °K.

Negative Thermal Expansion of Yb2Mo3O12 and Lu2Mo3O12

2008 ◽  
Vol 368-372 ◽  
pp. 1662-1664 ◽  
Author(s):  
X.L. Xiao ◽  
M.M. Wu ◽  
J. Peng ◽  
Y.Z. Cheng ◽  
Zhong Bo Hu
Keyword(s):  
Thermal Expansion ◽  
Solid State ◽  
Solid State Reaction ◽  
Linear Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Orthorhombic Structure ◽  
Conventional Solid State Reaction ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

Compounds Yb2Mo3O12 and Lu2Mo3O12 were prepared by conventional solid-state reaction. Their crystal structures and thermal expansion properties were investigated. It was found that Yb2Mo3O12 and Lu2Mo3O12 adopt orthorhombic structure and show negative thermal expansion (NTE) in the temperature range of 200-800 °C. Their a-axis and c-axis exhibit stronger contraction in the temperature range of 200-800 °C, while b-axis slightly expands in the temperature range of 200-300 °C and then contracts in the temperature range of 300-800 °C. The linear thermal expansion coefficients al of Yb2Mo3O12 and Lu2Mo3O12 are −5.17 × 10−6 °C−1 and −5.67 × 10−6 °C−1, respectively.

scholarly journals Studies on Thermophysical Properties of CaO and MgO by γ-Ray Attenuation

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
A. S. Madhusudhan Rao ◽  
K. Narender
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Thermophysical Properties ◽  
Linear Thermal Expansion ◽  
Temperature Dependent ◽  
Degree Polynomial ◽  
Attenuation Coefficients ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

The study on temperature dependent γ-ray attenuation and thermophysical properties of CaO and MgO has been carried out in the temperature range 300 K–1250 K using different energies of γ-beam, namely, Am (0.0595 MeV), Cs (0.66 MeV), and Co (1.173 MeV and 1.332 MeV) on γ-ray densitometer fabricated in our laboratory. The linear attenuation coefficients (μl) for the pellets of CaO and MgO as a function of temperature have been determined using γ-beam of different energies. The coefficients of temperature dependence of density have been reported. The variation of density and linear thermal expansion of CaO and MgO in the temperature range of 300 K–1250 K has been studied and compared with the results available in the literature. The temperature dependence of linear attenuation coefficients, density, and thermal expansion has been represented by second degree polynomial. Volume thermal expansion coefficients have been reported.

AB INITIO THERMODYNAMICS OF ZINC-BLENDE ZnS, ZnSe

2011 ◽  
Vol 25 (32) ◽  
pp. 4553-4561 ◽  
Author(s):  
HUAN-YOU WANG ◽  
HUI XU ◽  
JU-YING CAO ◽  
MING-JUN LI
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
Constant Pressure ◽  
Local Density ◽  
Linear Thermal Expansion ◽  
Plane Wave Method ◽  
Temperature Range ◽  
Zinc Blende ◽  
Good Agreement

The density function perturbation theory (DFPT) is employed to study the linear thermal expansion and heat capacity at constant pressure (with the quasiharmonic approximation). The calculations are performed using a pseudopotential plane wave method and local density approximation for the exchange-correlation potential. The calculated results of linear thermal expansion coefficient and heat capacity at constant pressure for zinc-blende ZnS , ZnSe are compared with the available experimental data in a wide temperature range. Generally, in low-temperature range, they have good agreement. However, in high-temperature range, due to anharmonic effect and other reasons, lead to larger errors for these properties between the theoretical results and available experimental data.

X-ray diffractometry of AlGaAs/GaAs superlattices and GaAs in the temperature range 5–295 K

1989 ◽  
Vol 22 (4) ◽  
pp. 372-375 ◽  
Author(s):  
G. Clec'h ◽  
G. Calvarin ◽  
P. Auvray ◽  
M. Baudet
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Low Temperatures ◽  
X Ray ◽  
Lattice Constants ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Gaas Substrates ◽  
Expansion Coefficients ◽  
Tetrahedrally Bonded

The temperature dependence of the lattice constants of Al x Ga1 − x As/GaAs superlattices MBE-grown on (001) oriented GaAs substrates was determined by X-ray diffractometry. The thermal expansion coefficients of these materials become negative at low temperatures, like that of GaAs and other tetrahedrally bonded covalent solids. The temperature dependence of the stress in these structures was also studied; although its value increases as temperature decreases, strain remains elastic down to 5 K.

scholarly journals Temperature-dependent structural behaviour of samarium cobalt oxide

2017 ◽  
Vol 32 (S2) ◽  
pp. S38-S42
Author(s):  
Matthew R. Rowles ◽  
Cheng-Cheng Wang ◽  
Kongfa Chen ◽  
Na Li ◽  
Shuai He ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Cobalt Oxide ◽  
Sol Gel ◽  
Linear Thermal Expansion ◽  
Rietveld Analysis ◽  
Structural Behaviour ◽  
Temperature Dependent ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Sol Gel Synthesis

The crystal structure and thermal expansion of the perovskite samarium cobalt oxide (SmCoO3) have been determined over the temperature range 295–1245 K by Rietveld analysis of X-ray powder diffraction data. Polycrystalline samples were prepared by a sol–gel synthesis route followed by high-temperature calcination in air. SmCoO3 is orthorhombic (Pnma) at all temperatures and is isostructural with GdFeO3. The structure was refined as a distortion mode of a parent $ Pm{\bar 3}m $ structure. The thermal expansion was found to be non-linear and anisotropic, with maximum average linear thermal expansion coefficients of 34.0(3) × 10−6, 24.05(17) × 10−6, and 24.10(18) × 10−6 K−1 along the a-, b-, and c-axes, respectively, between 814 and 875 K.

Effect of pressure on the thermal expansion coefficients of CeCu2 single crystals

1992 ◽  
Vol 181 (1-2) ◽  
pp. 293-298 ◽  
Author(s):  
Y. Uwatoko ◽  
H. Okita ◽  
G. Oomi ◽  
I. Umehara ◽  
Y. Ōnuki
Keyword(s):  
Thermal Expansion ◽  
Single Crystals ◽  
Effect Of Pressure ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients
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