Temperature dependence of lattice constants of the rare-earth hexaborides EuB6and GdB6

2001 ◽  
Vol 34 (2) ◽  
pp. 208-209 ◽  
Author(s):  
Yasuhiko Takahashi ◽  
Masayoshi Fujimoto ◽  
Masashi Tsuchiko ◽  
Ken-Ichi Ohshima
Keyword(s):  
Rare Earth ◽  
Temperature Dependence ◽  
Linear Thermal Expansion ◽  
X Ray ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Temperature Dependences ◽  
Expansion Coefficients ◽  
Ray Patterns ◽  
The Rare Earth

The temperature dependences of the lattice constants of single crystals of the rare-earth hexaborides EuB6and GdB6were determined by analysing the low-temperature X-ray patterns. The lattice constant decreases monotonously with decreasing temperature. The linear thermal expansion coefficients for the two compounds were also obtained by analysing the temperature dependence of the lattice constants.

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 Термическое расширение и люминесцентные свойства триортогерманатов CaLa-=SUB=-2-x-=/SUB=-Eu-=SUB=-x-=/SUB=-Ge-=SUB=-3-=/SUB=-O-=SUB=-10-=/SUB=- (x=0.0-0.6)

2018 ◽  
Vol 60 (2) ◽  
pp. 363
Author(s):  
O.А. Липина ◽  
Л.Л. Сурат ◽  
Я.В. Бакланова ◽  
И.Ф. Бергер ◽  
А.П. Тютюнник ◽  
...  
Keyword(s):  
Linear Thermal Expansion ◽  
Excitation Wavelength ◽  
X Ray Diffraction ◽  
Monoclinic System ◽  
Strain Anisotropy ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
First Time ◽  
Luminescence Characteristics

AbstractSolid solutions CaLa_2- x Eu_ x Ge_3O_10 ( x = 0.0–0.6, Δ x = 0.1) have been synthesized for the first time. The compounds are isostructural to CaLa_2Ge_3O_10, they crystallize in the monoclinic system, space group P 2_1/ c , Z = 4. The low-temperature X-ray diffraction studies have revealed the strain anisotropy of germanate CaLa_2Ge_3O_10 crystal lattice in the temperature range 80–298 K, and the linear thermal expansion coefficients have been calculated. The optical properties of the activated phases have been studied, and the influence of the dopant concentration and the excitation wavelength on the luminescence characteristics of the synthesized compounds has been established.

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.

Thermal expansion of the new perovskite substrates DyScO3 and GdScO3

2005 ◽  
Vol 20 (4) ◽  
pp. 952-958 ◽  
Author(s):  
M.D. Biegalski ◽  
J.H. Haeni ◽  
S. Trolier-McKinstry ◽  
D.G. Schlom ◽  
C.D. Brandle ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Expansion ◽  
Rare Earth ◽  
Lattice Spacing ◽  
Epitaxial Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Increasing Temperature

The thermal expansion coefficients of DyScO3 and GdScO3 were determined from298 to 1273 K using x-ray diffraction. The average thermal expansion coefficients of DyScO3 and GdScO3 were 8.4 and 10.9 ppm/K, respectively. No phase transitions were detected over this range, though the orthorhombicity decreased with increasing temperature. These thermal expansion coefficients are similar to other oxide perovskites (e.g., BaTiO3 or SrTiO3), making these rare-earth scandates promising substrates for the growth of epitaxial thin films of many oxide perovskites that have similar lattice spacing and thermal expansion coefficients.

Dielectric and thermal properties, expansion, and high-temperature plastic deformation of Cd4Na(VO4)3

1983 ◽  
Vol 16 (1) ◽  
pp. 133-135 ◽  
Author(s):  
S. C. Abrahams ◽  
K. Nassau ◽  
J. Ravez ◽  
A. Simon ◽  
R. Olazcuaga
Keyword(s):  
Phase Transition ◽  
Plastic Deformation ◽  
Second Harmonic ◽  
Linear Thermal Expansion ◽  
Optical Quality ◽  
Rapid Rise ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Sensitivity Level ◽  
Expansion Coefficients

Cd4Na(VO4)3 has been reported as crystallizing in space group Pn21 a with all atoms displaced no more than 1/4 Å, from the corresponding positions in prototypic Pnma. Such an atomic arrangement is expected to be ferroelectric. Large optical-quality crystals, with no phase transition between 300 K and the melting point at 1165 K, have been grown. The piezoelectric d 22 coefficient is less than 0.1  pCN−1 and second-harmonic generation is undetectable at a sensitivity level capable of measuring a signal less than 0.001 that produced by quartz. The crystal is hence centrosymmetric at the 99% confidence level. The lattice constants at 294 K are a = 9.8189(3), b = 7.0298(2), c = 5.3610(1) Å, with linear thermal expansion coefficients of α(a) = 14.4, α(b) = 10.8, α(c) = 21.0 × 10−6 K −1 between 294 and 973 K. Plastic deformation sets in above 1060 K with an accompanying rapid rise both in dielectric permittivity and conductance.

Temperature Dependence of Linear Thermal Expansion of CuGaSe2 Crystals

2012 ◽  
Vol 725 ◽  
pp. 171-174
Author(s):  
Akira Nagaoka ◽  
Kenji Yoshino ◽  
Tomoyasu Taniyama ◽  
Hideto Miyake
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Linear Thermal Expansion ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Lattice Constants ◽  
Traveling Heater Method ◽  
Increasing Temperature

CuGaSe2 single crystals were grown by a traveling heater method, which is one of the solution growth techniques. The temperature dependence of the X-ray diffraction of CuGaSe2 was determined between 10 and 300 K. The room temeprature XRD pattern of CuGaSe2 corresponds to the ICDD data. No secondary phases are observed in the spectrum. The lattice constant of the a-axis increases and that of the c-axis decreases with increasing temperature. The linear thermal expansion of the c-axis calculated from the lattice constants indicates a negative value from 10 to 100 K.

Thermal Stability of the Structural and Electronic Properties of Strain Symmetrized Sim Gen Superlattices and Ungraded, Nearly Relaxed Si1−x Gex

1992 ◽  
Vol 281 ◽  
Author(s):  
P. A. Dafesh ◽  
P. M. Adams ◽  
V. Arbet-Engels ◽  
K. L. Wang
Keyword(s):  
Thermal Expansion ◽  
Energy Shift ◽  
Buffer Layers ◽  
X Ray ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Structural And Electronic Properties ◽  
Expansion Coefficients ◽  
The Difference ◽  
Anneal Temperature

ABSTRACTIn this study, photoreflectance (PR) spectroscopy and x-ray rocking curves measurements were used to study the variation in strain configuration, defect propagation, structural properties and direct electronic transition energies in Sim Gen superlattices (SL) and nearly relaxed Si1−x Gex buffer layers grown on < 100 > Si as a function of annealing temperature. The in-plane (a│) and perpendicular (a┴) lattice constants of the alloy buffer layers are found to vary only slightly with anneal temperature, TA, up to a temperature To. For TA To, the in-plane strain changed from roughly zero a│ ≈ a┴ (relaxed) or a┴ > a│ (compressive) to a┴ > a│ (tensile). This change in strain configuration is believed to be caused by the difference in thermal expansion coefficients between the epilayer and the Si substrate. The anneal temperature T0 is also correlated with the disappearance of higher order x-ray harmonics from the SL. This point was also correlated with a large energy shift and broadening of the PR spectra from the SL. The shift in energy of the PR spectra is explained in terms of the interdiffusion of Si and Ge at SL heterointerfaces, and to a lesser degree, the strain induced by the above mentioned difference in thermal expansion coefficients. The PR spectra of the alloy E0 transitions are also observed to shift to higher energy with increasing TA.

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