scholarly journals Phase Transitions and Local Polarity above TC in a PbZr0.87Ti0.13O3 Single Crystal

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 286
Author(s):  
Iwona Lazar ◽  
Andrzej Majchrowski ◽  
Andrzej Soszyński ◽  
Krystian Roleder
Keyword(s):  
Phase Transitions ◽  
Solid Solutions ◽  
Piezoelectric Materials ◽  
Temperature Range ◽  
Limited Temperature ◽  
Similar Chemical ◽  
Limited Temperature Range ◽  
Optical Dielectric ◽  
Top Seeded Solution Growth ◽  
First Time

Solid solutions of PbZr1−xTixO3 (PZT) are one of the most widely used piezoelectric materials with perovskite structure. Despite the decades of research, the phase diagram of PZT reported in 1971 has not been resolved yet. Recently, it turned out that single crystals of good quality of these solid solutions can be grown. By means of top-seeded solution growth (TSSG) technique, we succeeded to grow a single PbZr0.87Ti0.13O3 crystal. Hence, a partial verification of the diagram could be performed through investigations of the optical, dielectric, pyroelectric and elastic properties of this crystal, in a wide temperature range. The obtained results confirmed that the PbZr0.87Ti0.13O3 crystal undergoes a sequence of phase transitions, such as those observed in ceramics of similar chemical composition. However, additional anomalies of investigated physical properties were observed and discussed. Moreover, the influence of electric field on optical properties has been investigated for the first time and has proven the existence of local polar character of the phase above TC in a limited temperature range.

scholarly journals Heat capacity of lithium tungstate single crystal by DSC calorimetry data in the temperature range of 319-997 K

2021 ◽  
Vol 2057 (1) ◽  
pp. 012048
Author(s):  
N I Matskevich ◽  
V N Shlegel ◽  
A A Chernov ◽  
D A Samoshkin ◽  
S V Stankus ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Phase Transitions ◽  
Single Crystal ◽  
Weight Control ◽  
Czochralski Technique ◽  
Temperature Range ◽  
First Time ◽  
Lithium Tungstate ◽  
Dsc Calorimetry ◽  
Calorimetry Data

Abstract The heat capacity of lithium tungstate single crystal (Li2WO4) was measured for the first time in the temperature range of 319-997 K. The experiments were carried out by DSC calorimetry. The Li2WO4 single crystal was first grown by low-temperature-gradient Czochralski technique with weight control. The temperature dependence of Li2WO4 heat capacity in the temperature range 319-997 K was monotonic. According to results of our studies, there were no phase transitions in Li2WO4 in the investigated temperature range.

Reduction of binary sulfate mixtures containing CuSO4 by H2

1976 ◽  
Vol 54 (23) ◽  
pp. 3651-3657 ◽  
Author(s):  
Fathi Habashi ◽  
Shaheer A. Mikhail
Keyword(s):  
Intermediate Product ◽  
The Other ◽  
Temperature Range ◽  
Other Hand ◽  
First Case ◽  
Limited Temperature ◽  
Limited Temperature Range ◽  
The Individual

The reduction of a binary sulfate mixture cannot be predicted from the behavior of the individual components. Thus, while CuSO4 is reduced to Cu at 400 °C and NiSO4 is reduced to Ni3S2, the sulfate mixture yields Cu, Ni3S2, and Cu2S. Also while FeSO4 is completely stable in H2 at 400 °C, (Cu,Fe) SO4 yields Cu and Cu5FeS4. The formation of Cu2S in the first case and Cu5FeS4 in the second was unexpected. On the other hand, (Cu,Mn)SO4 is stable in H2 up to 550 °C although pure CuSO4 is completely reduced at 400 °C. CoSO4 also interferes when reduced in presence of CuSO4, while Na2SO4, MgSO4, Al2(SO4)3, ZnSO4, CdSO4 do not interfere within limited temperature range. Of these only Na2SO4 forms a complex sulfate with CuSO4. No Cu2SO4 was identified when CuSO4 was reduced in presence of other sulfates although it is an intermediate product during the reduction of pure CuSO4.

Notizen: Austausch von Nitrit- gegen Bromidanionen in Na3NO3 / Replacement of Nitrite by Bromide Anions in Na3NO3

1989 ◽  
Vol 44 (8) ◽  
pp. 996-998 ◽  
Author(s):  
M. Jansen ◽  
W. Müller
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Solid Solutions ◽  
Room Temperature ◽  
Mixed Crystals ◽  
Miscibility Gap ◽  
Temperature Range ◽  
Collective Interactions

Na3O(NO2) and Na3OBr are isostructural and form solid solutions with a miscibility gap χ = 0.28 to 0.62 as referred to Na3OBrx(NO2)1-x, at room temperature. Above 593 Κ formation of mixed crystals was observed for all compositions. In contrast to pure Na3O(NO2), the solid solutions do not undergo any phase transition in the investigated temperature range from 293 Κ to 130 K. These findings reveal that collective interactions between the dynamically disordered NO2--groups are involved in the phase transitions of Na3NO3.

Controlled Growth of Germanium Nanowires via a Solid–Liquid–Solid (SLS) Mechanism

2012 ◽  
Vol 557-559 ◽  
pp. 523-529 ◽  
Author(s):  
Shih Fong Lee ◽  
Li Ying Lee ◽  
Yung Ping Chang
Keyword(s):  
Surface Density ◽  
High Surface ◽  
Average Diameter ◽  
Germanium Nanowires ◽  
Temperature Range ◽  
Au Film ◽  
Limited Temperature ◽  
Limited Temperature Range ◽  
Solid Liquid ◽  
Nano Wires

In this study, germanium nanowires (GeNWs) were grown directly on gold-evaporated germanium substrates by a solid-liquid-solid (SLS) mechanism in the temperature range 550°C- 650°C. The growth of GeNWs is very sensitive to the growth temperature and only in a limited temperature range (575°C-625°C) can GeNWs having excellent morphology and high surface density be successfully grown. These long, thin, and straight GeNWs have a high aspect ratio and are surrounded by an oxide layer. The composition of corresponding oxide layers is GeOx (x<2). As the thickness of Au film is decreased from 9 nm to 1 nm, the average diameter of GeNWs decreases from 119.3 nm to 38.5 nm. Our experimental results demonstrate that the diameter of germanium nano¬wires can be controlled by the thickness of Au metal film.

The effect of undercooling and Nd422 phase content on the nucleation of large Nd–Ba–Cu–O grains fabricated by top-seeded melt processing

1999 ◽  
Vol 14 (10) ◽  
pp. 3859-3863 ◽  
Author(s):  
N. Hari Babu ◽  
W. Lo ◽  
D. A. Cardwell ◽  
Y. Shi
Keyword(s):  
Melt Processing ◽  
Phase Content ◽  
Slow Cooling ◽  
Solidification Temperature ◽  
Growth Technique ◽  
Temperature Range ◽  
Limited Temperature ◽  
Peritectic Solidification ◽  
Limited Temperature Range ◽  
Single Grain

The nucleation and growth of NdBa2Cu3O7–δ (Nd123)–Nd4Ba2Cu2O10 (Nd422) single-grain composites in a controlled 1% O2 in N2 atmosphere were investigated in detail as a function of solidification temperature and Nd422 phase content using a top-seeded melt growth technique. A schematic process phase diagram in the peritectic solidification region of Nd–Ba–Cu–O (NdBCO) was constructed primarily from constant isothermal growth experiments at various temperatures for several compositions and used to fabricate large single-grain material by both isothermal and continuous slow cooling over a limited temperature range. The nucleation at the seed surface and subsequent growth of uniform grains was observed to depend critically on the controlled rate of grain growth and the temperature range over which solidification occurred.

The thermal field of an oil layer for phase transformations within a limited temperature range

2012 ◽  
Vol 50 (2) ◽  
pp. 265-272
Author(s):  
A. I. Filippov ◽  
K. K. Nandi ◽  
R. G. Fattakhov ◽  
T. A. Ishmuratov
Keyword(s):  
Phase Transformations ◽  
Thermal Field ◽  
Temperature Range ◽  
Limited Temperature ◽  
Limited Temperature Range
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