scholarly journals Doping induced dielectric anomaly below the Curie temperature in molecular ferroelectric diisopropylammonium bromide

2018 ◽  
Vol 5 (11) ◽  
pp. 181397 ◽  
Author(s):  
Kaige Gao ◽  
Binbin Zhang ◽  
Yunqing Cao ◽  
Xiaobing Chen
Keyword(s):  
Point Defects ◽  
Domain Walls ◽  
Ferroelectric Domain ◽  
Dielectric Anomaly ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Potential Applications ◽  
Structure Phase Transition

A dielectric anomaly induced by doping has been observed at about 340 K in chlorine-doped diisopropylammonium bromide. The dielectric anomaly has a switchable behaviour, which indicates potential applications on switches and sensors. Temperature-dependent Raman spectrum, X-ray diffraction and differential scanning calorimetry do not show any anomaly around the dielectric anomaly temperature, which prove that the dielectric anomaly does not come from structure phase transition and has no specific heat variety. It is assumed that this dielectric anomaly can be attributed to the freezing of ferroelectric domain walls induced by the pinning of point defects.

Multiple dielectric anomalies in xBiLaO3–(1 − x)PbTiO3 piezoelectrics

2008 ◽  
Vol 23 (2) ◽  
pp. 565-569 ◽  
Author(s):  
Runrun Duan ◽  
Michael S. Haluska ◽  
Robert F. Speyer
Keyword(s):  
Differential Scanning Calorimetry ◽  
Dielectric Constant ◽  
Excellent Agreement ◽  
Structural Changes ◽  
Dielectric Anomaly ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermally Induced ◽  
X Ray ◽  
Higher Temperature

Compositions of xBiLaO3–(1 − x) PbTiO3 over the range 0 ≤ x ≤ 0.225 were calcined and sintered. The dielectric constant with temperature and differential scanning calorimetry measurements were in excellent agreement with respect to Curie-like tetragonal to cubic transformations starting at 495 °C for pure PbTiO3, shifting to lower temperatures with increasing x. For compositions of x ≥ 0.05, a second higher-temperature (∼600 °C) endotherm, and matching dielectric anomaly, were consistently observed, for which there were no structural changes indicated by hot-stage x-ray diffraction. This transformation was speculated to be based on a thermally induced desegregation of B-site cations.

Darstellung und magnetische Eigenschaften einiger kristalliner Nitroxidradikale/Synthesis and Magnetic Properties of Some Crystalline Nitroxide Radicals

2000 ◽  
Vol 55 (7) ◽  
pp. 567-575 ◽  
Author(s):  
K. Griesar ◽  
E. A. Soto-Bustamante ◽  
W. Haase
Keyword(s):  
Differential Scanning Calorimetry ◽  
Magnetic Properties ◽  
Exchange Interactions ◽  
Antiferromagnetic Exchange ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Nitroxide Radicals ◽  
Scanning Calorimetry ◽  
Polarizing Microscopy ◽  
X Ray

Abstract The syntheses of different nitroxide radicals are reported. The thermal behaviour of the ni­ troxide radicals was examined by polarizing microscopy, differential scanning calorimetry as well as X-ray diffraction experiments. Temperature dependent magnetic susceptibility mea­surements were carried out in order to determine the magnetic properties of these nitroxide radicals. The majority of the radicals presented here show weak antiferromagnetic exchange interactions.

scholarly journals Polymorphism of a hexadecane–heptadecane binary system in nanopores

RSC Advances ◽  
2017 ◽  
Vol 7 (18) ◽  
pp. 10737-10747 ◽  
Author(s):  
Jian Sui ◽  
Shi Qi Zhang ◽  
Min Zhai ◽  
Fang Tian ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Binary System ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Scanning Calorimetry ◽  
Porous Glasses ◽  
X Ray ◽  
Phase Behaviors

Phase behaviors of a hexadecane–heptadecane (n-C16H34–C17H36, C16–C17) binary system in the bulk and in nanopores of controlled porous glasses (CPGs) are investigated using differential scanning calorimetry (DSC) and temperature-dependent powder X-ray diffraction (XRD).

Novel Temperature Dependent Process for α-Al2O3 Platelets

2012 ◽  
Vol 182-183 ◽  
pp. 104-109
Author(s):  
Cheng Long Yu ◽  
Xin Hao ◽  
Hong Tao Jiang ◽  
Li Li Wang ◽  
Zheng Guang Zhang ◽  
...  
Keyword(s):  
Ternary System ◽  
Molten Glass ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hand Part

α-Al2O3 platelets were prepared in the interface of Na2O-CaO-SiO2 glass induced by Al. Phase identification was accomplished by X-ray diffraction analysis. The morphology of the platelets was observed using an Environmental Scanning Electron Microscopy (ESEM). The changes for the mixtures of the Al powders and the glass powders that occurred during heating were characterized by a combination of differential scanning calorimetry (DSC) and thermalgravimety(TG) on a multi-functional instrument. Confirmed by XRD and ESEM, at 1200°C, the prepared platelets have mean diameters between 400nm and 1000nm. Most of them are aggregated and part of them through intergrowth. The crystals develop from the interface between glass and Al, and can form good moistening with the glass matrix. DSC/TG shows that γ-Al2O3 formed by oxidation of Al, transforms into α-Al2O3 and grow into the platelet α-Al2O3 crystals owing to the molten Al and the molten glass. On the other hand, part of the molten Al erodes into the glass and makes the deviation of the Na2O-CaO-SiO2 ternary system into Na2O-Al2O3-SiO2 ternary system, resulting in the formation of NaAlSiO4.

Discotic liquid crystals of transition metal complexes 44: synthesis of hexaphenoxy-substituted phthalocyanine derivatives showing spontaneous perfect homeotropic alignment

2012 ◽  
Vol 16 (10) ◽  
pp. 1114-1123 ◽  
Author(s):  
Masaaki Ariyoshi ◽  
Makiko Sugibayashi-Kajita ◽  
Ayumi Suzuki-Ichihara ◽  
Takayuki Kato ◽  
Tenpei Kamei ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystals ◽  
Transition Metal ◽  
Transition Metal Complexes ◽  
Discotic Liquid Crystals ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Homeotropic Alignment

We have synthesized novel hexaphenoxy-substituted phthalocyanine derivatives, 2-(12-hydroxydodecyloxy)-3-methoxy-9,10,16,17,23,24-hexakis(3,4-di-n-alkoxyphenoxy)phthalocyaninato copper(II) (abbreviated as Cn(OC12OH)PcCu : n = 10, 12, 14), and investigated their columnar mesomorphism and homeotropic alignment property. These hexaphenoxy-substituted Pc derivatives could be successfully isolated and purified from the mixture products by polarity difference. It was revealed by using polarizing optical microscopic observations, differential scanning calorimetry and temperature-dependent X-ray diffraction studies that each of the hexaphenoxy-substituted Pc derivatives has plural mesophases, and that the tetragonal columnar (Coltet) mesophase shows spontaneous perfect homeotropic alignment between two non-surface-treated glass plates without any defects and polydomain boundaries.

scholarly journals Tris(ethylenediamine) Cobalt(II) and Manganese(II) Nitrates

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 472
Author(s):  
Miguel Cortijo ◽  
Ángela Valentín-Pérez ◽  
Mathieu Rouzières ◽  
Rodolphe Clérac ◽  
Patrick Rosa ◽  
...  
Keyword(s):  
Phase Transition ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Scanning Calorimetry ◽  
Orbital Contribution ◽  
X Ray ◽  
Reversible Phase Transition ◽  
Heat Capacity Measurements ◽  
Reversible Phase

Octahedral tris(ethylenediamine) coordination complexes demonstrate helicoidal chirality, due to the arrangement of the ligands around the metal core. The enantiomers of the nitrate salts [Ni(en)3](NO3)2 and [Zn(en)3](NO3)2 spontaneously resolve to form a mixture of conglomerate crystals, which present a reversible phase transition from space group P6322 to enantiomorphic P6522 or P6122, with the latter depending on the handedness of the enantiomer. We report here the synthesis and characterization of [Mn(en)3](NO3)2 and [Co(en)3](NO3)2, which are isostructural to the Zn(II) and Ni(II) derivatives. The Mn(II) analogue undergoes the same phase transition centered at 150(2) K, as determined by single-crystal X-ray diffraction, Raman spectroscopy, and differential scanning calorimetry. The Co(II) derivative does not demonstrate a phase transition down to 2 K, as evidenced by powder X-ray diffraction and heat capacity measurements. The phase transition does not impact the magnetic properties of the Ni(II) and Mn(II) analogues; these high spin compounds display Curie behavior that is consistent with S = 1 and 5/2, respectively, down to 20 K, while the temperature-dependent magnetic moment for the Co(II) compound reveals a significant orbital contribution.

scholarly journals Synthesis, Structure, and Dielectric Properties of (3-Nitroanilinium) (18-Crown) (PF6)

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1028
Author(s):  
Le Wang ◽  
Liu-lei Qin ◽  
Yang Liu ◽  
Peng Wang ◽  
Hui-ting Xu ◽  
...  
Keyword(s):  
Variable Temperature ◽  
Structural Phase ◽  
Dielectric Measurements ◽  
Slow Evaporation ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Scanning Calorimetry ◽  
One Dimensional ◽  
X Ray ◽  
Potential Energy Calculations

(3-Nitroanilinium) (18-crown) (PF6) (1), which is an organic-inorganic hybrid containing one-dimensional chains of hydrogen-bonded supramolecular cations, was synthesized under slow evaporation conditions and subjected to differential scanning calorimetry, temperature-dependent dielectric measurements, and variable-temperature single-crystal X-ray diffraction analysis. These analyses revealed the occurrence of a reversible structural phase transition [P21/n P21/c] at 223 K and a dielectric anomaly, which, based on the results of structural analysis and potential energy calculations, was attributed to the synergistic effect between the pendulum-like motion of the nitro group in the supramolecular cation, (3-nitroanilinium)(18-crown), and the order-disorder motion of PF6− anions.

The Reuse of Oligomeric Materials from the Waste of Poly(phenylene sulfide) Production

2012 ◽  
Vol 550-553 ◽  
pp. 2447-2451
Author(s):  
Li Zhu ◽  
Xiang Jie Li ◽  
Hai Bing Xu ◽  
Ai Qun Gu ◽  
Zi Li Yu
Keyword(s):  
Raw Materials ◽  
Filler Materials ◽  
Thermal Transition ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Plastic Coating ◽  
Sulfide Production ◽  
Potential Applications ◽  
Phenylene Sulfide

In order to reuse the waste originated from poly(phenylene sulfide) (PPS) production in stead of combustion, the oligomeric materials in the waste were recovered as raw materials. The recovered materials, then, were used to react with sulfur in molten state to produce polymeric resin. The structure and thermal property of oligomeric materials and their derived polymer were characterized by elemental analysis, infrared spectroscopy, X-ray diffraction and differential scanning calorimetry. The results showed that oligomeric materials are a series of PPS oligomers, and their derived polymer is poly(arylene sulfide)s (PAS). The thermal transition temperatures of obtained PAS are higher than those of PPS oligomers, which are attributed to the increase of molecular weight. It is desired that the yielding PAS has potential applications as plastic, coating, or filler materials.

Thin Films of Semiconducting SnSi Alloys Grown by Pulsed Laser Deposition

1994 ◽  
Vol 358 ◽  
Author(s):  
Randolph E. Treece ◽  
J. S. Horwitz ◽  
D. B. Chrisey ◽  
J. Tang ◽  
R. S. Williams
Keyword(s):  
Pulsed Laser Deposition ◽  
Photoelectron Spectroscopy ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Rays ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Target Holder ◽  
X Ray ◽  
Potential Applications

ABSTRACTSemiconducting SnxSi1−x (0≤x≤0.6) thin-film alloys have been grown by pulsed laser deposition (PLD). These new materials are amorphous to X-rays and display small positive optical band gaps, suggesting potential applications in solar cells. The tin silicide films were grown by depositing very thin (1–30 Å) alternating atomic layers from individual Sn and Si targets utilizing an automated multi-target holder coupled to a conventional PLD system. The value of x was selected by controlling the thickness of the atomic layers. The films were characterized by X-ray diffraction, optical absorption, Rutherford backscattering spectroscopy, temperature-dependent resistivity, and X-ray photoelectron spectroscopy. Tin segregation is prevented by keeping the Sn layer thickness below a critical value. Compositions beyond x > 0.6 led to semimetallic SnxSi1−x films with tin crystallites.

Studies on the Preparation, Characterization and Solubility of -Cyclodextrin-Roxythromycin Inclusion Complexes

2009 ◽  
Vol 2 (2) ◽  
pp. 523-530
Author(s):  
D. Nagasamy Venkatesh ◽  
S. Karthick ◽  
M. Umesh ◽  
G. Vivek ◽  
R.M. Valliappan ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Inclusion Complexes ◽  
Phase Solubility ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ir Studies ◽  
Poorly Soluble ◽  
Poorly Soluble Drug

Roxythromycin/ β-cyclodextrin (Roxy/ β-CD) dispersions were prepared with a view to study the influence of β-CD on the solubility and dissolution rate of this poorly soluble drug. Phase-solubility profile indicated that the solubility of roxythromycin was significantly increased in the presence of β-cyclodextrin and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Physical characterization of the prepared systems was carried out by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD) and IR studies. Solid state characterization of the drug β-CD binary system using XRD, FTIR and DSC revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement of dissolution rate.

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