Structural phase transition and negative thermal expansion in Cu1.8Zn0.2V2–x P x O7 solid solutions

2022 ◽  
Author(s):  
Koshi Takenaka ◽  
Masato Kano ◽  
Ryota Kasugai ◽  
Kohei Takada ◽  
Koki Eto ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Structural Phase ◽  
Negative Thermal Expansion ◽  
Peak Position ◽  
Crystallographic Analysis ◽  
Resin Matrix ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Lower Dielectric Constant ◽  
Microstructural Effects

Abstract Negative thermal expansion (NTE) is exhibited over the entire x range for Cu1.8Zn0.2V2–xPxO7. In particular, dilatometric measurements using epoxy resin matrix composites containing the spray-dried powder demonstrated that the thermal expansion suppressive capability was almost unchanged for x≤0.1. With increasing x, the x-ray diffraction peak position moves systematically, but some peaks are extremely broad and/or asymmetric, suggesting disorder in the internal structure. The crystallographic analysis confirmed NTE enhancement by microstructural effects at least for x=0.2. Preliminary measurements suggest higher resistivity and lower dielectric constant than that of pure vanadate, which is suitable for application to electronic devices.

scholarly journals Crystallography relevant to Mars and Galilean icy moons: crystal behavior of kieserite-type monohydrate sulfates at extraterrestrial conditions down to 15 K

IUCrJ ◽  
2022 ◽  
Vol 9 (2) ◽  
Author(s):  
Manfred Wildner ◽  
Boris A. Zakharov ◽  
Nikita E. Bogdanov ◽  
Dominik Talla ◽  
Elena V. Boldyreva ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Structural Phase ◽  
Negative Thermal Expansion ◽  
Remote Sensing Data ◽  
X Ray Diffraction ◽  
Icy Moons ◽  
Expansion Behavior ◽  
Anisotropic Expansion ◽  
Structural Details ◽  
Celestial Bodies

Monohydrate sulfate kieserites (M 2+SO4·H2O) and their solid solutions are essential constituents on the surface of Mars and most likely also on Galilean icy moons in our solar system. Phase stabilities of end-member representatives (M 2+ = Mg, Fe, Co, Ni) have been examined crystallographically using single-crystal X-ray diffraction at 1 bar and temperatures down to 15 K, by means of applying open He cryojet techniques at in-house laboratory instrumentation. All four representative phases show a comparable, highly anisotropic thermal expansion behavior with a remarkable negative thermal expansion along the monoclinic b axis and a pronounced anisotropic expansion perpendicular to it. The lattice changes down to 15 K correspond to an `inverse thermal pressure' of approximately 0.7 GPa, which is far below the critical pressures of transition under hydrostatic compression (Pc ≥ 2.40 GPa). Consequently, no equivalent structural phase transition was observed for any compound, and neither dehydration nor rearrangements of the hydrogen bonding schemes have been observed. The M 2+SO4·H2O (M 2+ = Mg, Fe, Co, Ni) end-member phases preserve the kieserite-type C2/c symmetry; hydrogen bonds and other structural details were found to vary smoothly down to the lowest experimental temperature. These findings serve as an important basis for the assignment of sulfate-related signals in remote-sensing data obtained from orbiters at celestial bodies, as well as for thermodynamic considerations and modeling of properties of kieserite-type sulfate monohydrates relevant to extraterrestrial sulfate associations at very low temperatures.

Microstructural effects on negative thermal expansion extending over a wide temperature range in β-Cu1.8Zn0.2V2O7

2018 ◽  
Vol 113 (18) ◽  
pp. 181902 ◽  
Author(s):  
N. Katayama ◽  
K. Otsuka ◽  
M. Mitamura ◽  
Y. Yokoyama ◽  
Y. Okamoto ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Wide Temperature Range ◽  
Negative Thermal Expansion ◽  
Temperature Range ◽  
Microstructural Effects

Effect of Annealing Temperature and External Tensile Stress on Negative Thermal Expansion to Cold Rolled Ti–23Nb–0.7Ta–2Zr Alloy

2020 ◽  
Vol 12 (9) ◽  
pp. 1409-1412
Author(s):  
Jeong-Tae Moon ◽  
Tae-Hyun Nam
Keyword(s):  
Thermal Expansion ◽  
Annealing Temperature ◽  
Negative Thermal Expansion ◽  
Constant Load ◽  
External Stress ◽  
Expansion Rate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cold Rolled ◽  
The Difference

The effect of annealing temperature and external stress on the thermal expansion of a Ti–23Nb–0.7Ta–2Zr alloy were investigated by means of thermal expansion tests under constant load and X-ray diffraction (XRD). Negative thermal expansion (NTE), which is a shrinkage during heating, was observed in both a cold rolled and annealed specimens. The intensity of (200)β peak decreased while that of (211)β peak increased as the annealing temperature increased. The difference in expansion rate between 50 °C and 250 °C is found to decrease with an increasing annealing temperature from 600 °C to 800 °C, above which it kept almost constant. The expansion rate decreased as the applied stress increased.

Thermally boosted upconversion and downshifting luminescence in Sc2(MoO4)3:Yb/Er with two-dimensional negative thermal expansion

2021 ◽  
Author(s):  
Jinsheng Liao ◽  
Minghua Wang ◽  
Fulin Lin ◽  
Zhuo Han ◽  
Datao Tu ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Near Infrared ◽  
Negative Thermal Expansion ◽  
Thermal Quenching ◽  
Relative Sensitivity ◽  
Strong Temperature Dependence ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Higher Temperature

Abstract Lanthanide (Ln3+)-doped phosphors generally suffer from thermal quenching, in which their photoluminescence (PL) intensities decrease at the higher temperature. Herein, we report a class of unique two-dimensional negative-thermal-expansion phosphor of Sc2(MoO4)3:Yb/Er. By virtue of the reduced distances between sensitizers and emitters as well as confined energy migration with increasing the temperature, a 45-fold enhancement of green upconversion (UC) luminescence and a 450-fold enhancement of near-infrared downshifting (DS) luminescence of Er3+ are achieved from 25 to 500 ˚C. The thermally boosted UC and DS luminescence mechanism is systematically investigated through in situ temperature-dependent Raman spectroscopy, synchrotron X-ray diffraction and PL dynamics. Moreover, the luminescence lifetime of 4I11/2 of Er3+ in Sc2(MoO4)3:Yb/Er displays a strong temperature dependence, enabling ratiometric thermometry with the highest relative sensitivity of 13.4%/K at 298 K. These findings may gain a vital insight into the design of negative-thermal-expansion Ln3+-doped phosphors for versatile applications.

Variable-Temperature Microcrystal X-ray Diffraction Studies of Negative Thermal Expansion in the Pure Silica Zeolite IFR

2001 ◽  
Vol 123 (23) ◽  
pp. 5453-5459 ◽  
Author(s):  
Luis A. Villaescusa ◽  
Philip Lightfoot ◽  
Simon J. Teat ◽  
Russell E. Morris
Keyword(s):  
Thermal Expansion ◽  
Variable Temperature ◽  
Negative Thermal Expansion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pure Silica

scholarly journals Structural and Thermal Unusual Properties in Invar Behavior of Ni-Mn Alloys

2020 ◽  
Vol 17 (2(SI)) ◽  
pp. 0629
Author(s):  
Salih Darweesh et al.
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Lattice Distortion ◽  
Negative Thermal Expansion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ferromagnetic Metals ◽  
Invar Effect

The Invar effect in 3D transition metal such as Ni and Mn, were prepared on a series composition of binary Ni1-xMnx system with x=0.3, 0.5, 0.8 by using powder metallurgy technique. In this work, the characterization of structural and thermal properties have been investigated experimentally by X-ray diffraction, thermal expansion coefficient and vibrating sample magnetometer (VSM) techniques. The results show that anonymously negative thermal expansion coefficient are changeable in the structure. The results were explained due to the instability relation between magnetic spins with lattice distortion on some of ferromagnetic metals.    

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