Thermal expansion coefficients of strontium - barium niobate single crystals in the vicinity of the phase transition point

2017 ◽  
Vol 52 (8) ◽  
pp. 1600368 ◽  
Author(s):  
Robert Paszkowski ◽  
Krystyna Wokulska ◽  
Jan Dec
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Single Crystals ◽  
Transition Point ◽  
Phase Transition Point ◽  
Strontium Barium Niobate ◽  
Strontium Barium ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

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

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.

scholarly journals Extraordinary anisotropic thermal expansion in photosalient crystals

IUCrJ ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 83-89 ◽  
Author(s):  
Khushboo Yadava ◽  
Gianpiero Gallo ◽  
Sebastian Bette ◽  
Caroline Evania Mulijanto ◽  
Durga Prasad Karothu ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Solid State ◽  
Metal Complexes ◽  
Single Crystals ◽  
Room Temperature ◽  
Volumetric Thermal Expansion ◽  
Anisotropic Thermal Expansion ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Multifunctional Properties

Although a plethora of metal complexes have been characterized, those having multifunctional properties are very rare. This article reports three isotypical complexes, namely [Cu(benzoate)L 2], where L = 4-styrylpyridine (4spy) (1), 2′-fluoro-4-styrylpyridine (2F-4spy) (2) and 3′-fluoro-4-styrylpyridine (3F-4spy) (3), which show photosalient behavior (photoinduced crystal mobility) while they undergo [2+2] cycloaddition. These crystals also exhibit anisotropic thermal expansion when heated from room temperature to 200°C. The overall thermal expansion of the crystals is impressive, with the largest volumetric thermal expansion coefficients for 1, 2 and 3 of 241.8, 233.1 and 285.7 × 10−6 K−1, respectively, values that are comparable to only a handful of other reported materials known to undergo colossal thermal expansion. As a result of the expansion, their single crystals occasionally move by rolling. Altogether, these materials exhibit unusual and hitherto untapped solid-state properties.

Phase Transition Studies in PMBAB and PEBAB

1984 ◽  
Vol 39 (7) ◽  
pp. 696-699 ◽  
Author(s):  
V. G. K. M. Pisipati ◽  
N. V. S. Rao
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Molar Volume ◽  
Ultrasonic Velocity ◽  
Adiabatic Compressibility ◽  
First Order ◽  
Thermal Expansion Coefficients ◽  
Methylene Unit ◽  
Expansion Coefficients ◽  
Transition Studies

The variation of density and ultrasonic velocity with temperature in N-(p-methoxybenzylidene)- p-aminobenzonitrile (PMBAB) and N-(p-ethoxybenzylidene)-p-aminobenzonitrile (PEBAB) are presented. The density jumps and thermal expansion coefficients suggest the nematic-isotropic transition of both compounds to be of first order. The adiabatic compressibility βad, molar sound velocity Rn and molar compressibility Aw are computed. The contribution of a methylene unit to the molar volume is found to be higher than literature values. The anomalous ultrasonic velocity dip at the nematic-isotropic transition for both compounds is found to be high; the value is many times those found for other nematic-isotropic or nematicsmectic A transitions.

scholarly journals Investigation of the changes in hydrogen bonding accompanying the structural reorganization at 103 K in ammonium iodate

2019 ◽  
Vol 75 (2) ◽  
pp. 152-159
Author(s):  
W. G. Marshall ◽  
R. H. Jones ◽  
K. S. Knight ◽  
C. R. Pulham ◽  
R. I. Smith
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Hydrogen Bonding ◽  
Structural Features ◽  
Neutron Powder Diffraction ◽  
Halogen Bonds ◽  
Structural Reorganization ◽  
Thermal Expansion Coefficients ◽  
Per Se ◽  
Expansion Coefficients

Neutron powder diffraction has been used to observe the changes in hydrogen bonding that occur as a function of temperature in ND4IO3 and, thus, determine the structural features that occur during the low-temperature (103 K) phase transition. It is shown that in the deuterated material the change is not a phase change per se but rather a structural reorganization in which the hydrogen bonding becomes firmly locked in at the phase transition temperature, and stays in this configuration upon further cooling to 4.2 K. In addition, both the differences and changes in the axial thermal expansion coefficients in the region 100–290 K can be explained by the changes involving both the hydrogen bonding and the secondary I...O halogen bonds.

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.

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