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 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.

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.

Mechanical and thermodynamic properties of intermetallic compounds in the Ni–Ti system

2017 ◽  
Vol 31 (22) ◽  
pp. 1750161 ◽  
Author(s):  
Y. F. Li ◽  
S. L. Tang ◽  
Y. M. Gao ◽  
S. Q. Ma ◽  
Q. L. Zheng ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Intermetallic Compounds ◽  
Room Temperature ◽  
Linear Thermal Expansion ◽  
Harmonic Approximation ◽  
Anisotropic Elasticity ◽  
First Principles Calculations ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Zirconia Toughened Alumina

The mechanical and thermodynamic properties of intermetallic compounds in the Ni–Ti system are studied by first-principles calculations. All phases show anisotropic elasticity in different crystallographic directions, in which Ni3Ti and NiTi2 are approaching the isotropy structure. The elastic moduli and Vicker’s hardness of Ni–Ti system intermetallic compounds decrease in the following order: Ni3Ti [Formula: see text] B2_NiTi [Formula: see text] B19[Formula: see text]_NiTi [Formula: see text] NiTi2, and Ni3Ti shows the best mechanical properties. The intrinsic ductile nature of Ni–Ti compounds is confirmed by the obtained [Formula: see text]/[Formula: see text] ratio. The temperature dependence of linear thermal expansion coefficients (LTECs) of the compounds is estimated by the quasi-harmonic approximation (QHA) method. Ni3Ti shows the largest values among all Ni–Ti intermetallic compounds. At room temperature, the LTEC for Ni3Ti is 8.92 × 10[Formula: see text] K[Formula: see text], which falls in between the LTEC of zirconia toughened alumina (ZTA) (7.0–9.5 × 106 K[Formula: see text]) and iron matrix (9.2–16.9 × 106 K[Formula: see text]); i.e., the thermal matching of the ZTA/iron composite will be improved by introducing Ni3Ti intermetallic compound into their interface. Other thermodynamic properties such as sound velocity and Debye temperature are also obtained.

Measurement of thermal expansion coefficient of substrate GGG and its epitaxial layer YIG

1999 ◽  
Vol 14 (1) ◽  
pp. 2-4 ◽  
Author(s):  
Rui-sheng Liang ◽  
Feng-chao Liu
Keyword(s):  
Thin Film ◽  
Thermal Expansion ◽  
Single Crystal ◽  
Thermal Expansion Coefficient ◽  
Epitaxial Layer ◽  
Expansion Coefficient ◽  
Linear Thermal Expansion ◽  
New Method ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

A new method is used in measuring the linear thermal expansion coefficients in composite consisting of a substrate Gd3Ga2Ga3O12 (GGG) and its epitaxial layer Y3Fe2Fe3O12 (YIG) within the temperature range 13.88 °C–32.50 °C. The results show that the thermal expansion coefficient of GGG in composite is larger than that of the GGG in single crystal; the thermal expansion coefficient of thick film YIG is also larger than that of thin film. The results also show that the thermal expansion coefficient of a composite consisting of film and its substrate can be measured by using a new method.

Variations of lattice constants and thermal expansion coefficients of indium at high pressure and high temperature

2018 ◽  
Vol 38 (4) ◽  
pp. 406-413 ◽  
Author(s):  
Yusaku Takubo ◽  
Hidenori Terasaki ◽  
Tadashi Kondo ◽  
Shingo Mitai ◽  
Seiji Kamada ◽  
...  
Keyword(s):  
High Pressure ◽  
Thermal Expansion ◽  
High Temperature ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

Crystal Distortion Associated with Magnetic Ordering in Alpha Iron Oxide and Manganese Carbonate

1972 ◽  
Vol 16 ◽  
pp. 390-395 ◽  
Author(s):  
W. S. McCain ◽  
D. L. Albright
Keyword(s):  
Thermal Expansion ◽  
Lattice Constant ◽  
Room Temperature ◽  
Axial Ratio ◽  
Manganese Carbonate ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Position Parameter ◽  
Oxygen Distance

AbstractThe magnetic crystal disrortion of weakly ferromagnetic α-Fe2O3 was investigated by x-ray diffraction techniques. Here crystal distortion is taken as the temperature dependent changes of lattice constants and thermal expansion coefficients. Moreover, the oxygen position parameter and the carbon-oxygen distance of MnCO3 were determined.The lattice constants and thermal expansion coefficients of α-Fe2O3 were measured from room temperature down to 243°K. The crystal distortion, as measured by the changes in lattice constants, thermal expansion coefficients and axial ratio, was found to be highly anisotropic. The co hexagonal lattice constant was influenced very slightly by magnetic distortion; it changed only by 0.01 percent between room temperature and the Morin temperature of 254°K. On the other hand, the ao lattice constant changes by 0.11 percent between room temperature and the Morin temperature. The thermal expansion coefficients of the lattice constants showed a similar contrast. The co coefficient was found to be independent of temperature from room temperature down to the Morin temperature. However, in the same temperature range, the ao coefficient showed an anomalous increase with decreasing temperature. In addition, the ao coefficient showed an infinite discontinuity at the Morin temperature.The change in the axial ratio with temperature suggests that the net weak ferromagnetic moment of α-Fe2O3 reaches a maximum at 275°K.The oxygen position parameter, x, in MnCO3 as determined from two reflections has a value of 0.2702 ± 0.001. The carbon-oxygen distance as calculated from the lattice constants and the oxygen position parameter is 1.29 ±0.002 Å. This value is another confirmation of the Pauling theory of the resonating carbonate structure.

Dimensional and Locational Integrity in the Replication of Polymeric Microdevices

2007 ◽  
Author(s):  
Byoung Hee You ◽  
Daniel S. Park ◽  
Ping-Chuan Chen ◽  
Wilfredo M. Caceres ◽  
Dimitris E. Nikitopoulos ◽  
...  
Keyword(s):  
Linear Thermal Expansion ◽  
Hot Embossing ◽  
Microtiter Plate ◽  
Microfluidic Platforms ◽  
Molding Process ◽  
Thermal Expansion Coefficients ◽  
Molded Parts ◽  
Expansion Coefficients ◽  
Geometric Variation

In molding, geometric variation of molded parts is inevitable since the parts have a thermal history, including expansion and shrinkage, during the molding process. Shrinkage induces variation between the designed dimensions and locations of features on molded parts while the parts are cooled. Characterization of the variation is necessary to ensure dimensional and location integrity. Hot embossing and injection molding were performed in order to assess variation. Measurements were made using a Measurescope (MM-22, Nikon Corp., Kawasaki, Japan). The measured locations and dimensions were compared to estimates obtained using a simple model based on the linear thermal expansion coefficients (CTE) of the molded materials. The measured and the estimated shrinkage from hot embossing were incorporated in the fabrication of microtiter plate-based polymer microfluidic platforms.

Assessment of phase transition and thermal expansion coefficients by means of secondary multiple reflections of Renninger scans

2019 ◽  
Vol 52 (6) ◽  
pp. 1271-1279
Author(s):  
Adenilson O. dos Santos ◽  
Rossano Lang ◽  
José M. Sasaki ◽  
Lisandro P. Cardoso
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Structural Phase ◽  
Angular Position ◽  
Lattice Parameters ◽  
Rochelle Salt ◽  
Multiple Reflections ◽  
Multiple Diffraction ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

This paper reports the successful extension of the basis of the X-ray multiple diffraction phenomenon in the assessment of structural phase transitions and the determination of thermal expansion coefficients along three crystallographic directions, using synchrotron radiation Renninger scans. Suitable simultaneous four-beam cases have accurately resolved the lattice-parameter variation in a nearly perfect single-crystal Rochelle salt using a high-stability temperature apparatus. Secondary reflections observed in the Renninger patterns, chosen by their sensitivity to the shifts in angular position as a function of temperature, have allowed the detection of a monoclinic to orthorhombic phase transition, as well as subtle expansions of all the basic lattice parameters, i.e. without having to carry out measurements on each crystal axis. The thermal expansion coefficients have been estimated from the linear fit of the temperature dependence of the lattice parameters, and are in agreement with those reported in the literature.

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