Novel Near-Room-Temperature Type I Multiferroic: Pb(Fe0.5Ti0.25W0.25)O3 with Coexistence of Ferroelectricity and Weak Ferromagnetism

2012 ◽  
Vol 24 (14) ◽  
pp. 2664-2672 ◽  
Author(s):  
Sebastián A. Larrégola ◽  
José C. Pedregosa ◽  
Miguel Algueró ◽  
Ricardo Jiménez ◽  
Mar García-Hernandez ◽  
...  
Keyword(s):  
Room Temperature ◽  
Weak Ferromagnetism ◽  
Type I

scholarly journals Atran-analoge Verbindungen des Typs / Atrane Analogous Compounds of the Type

1984 ◽  
Vol 39 (3) ◽  
pp. 341-351 ◽  
Author(s):  
Joseph Grobe ◽  
Gerald Henkel ◽  
Bernt Krebs ◽  
Nikolaos Voulgarakis
Keyword(s):  
Structure Analysis ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Trigonal Bipyramid ◽  
Angular Distortion ◽  
Type I ◽  
Tetrahedral Coordination ◽  
Cage Compounds ◽  
X Ray ◽  
H Nmr

Heterocyclic cage compounds of type I (compounds 8-10) have been prepared by condensation reactions of 1,2,2-trifunctional disilanes Me(R)XSiSiMeX2 (R = Me, Ph, OEt; X = NMe2, OEt) with triethanolamine using the “Dilution Principle”. The starting compounds are obtained by Si-Me cleavage of Si2Me6 with acetylchloride/AlCl3 followed by either aminolysis with HNMe2 or alcoholysis with EtOH. 1H NMR spectra indicate N→Si(1) intraction with the more acidic Si atom in 8 and 9. This result is proved by the X-ray structure analysis of 8 (monoclinic, P21/c; a = 7,088(2), b = 15,070(4), c = 12,701(4) Å, β = 104,96(2) at -130 °C, Z = 4); the Si(1)···N distance is found to be 2,768 Å , connected with a significant angular distortion of the tetrahedral coordination around Si(1) towards a trigonal bipyramid. In compound 10, too, N→Si(1) coordination is observed at room temperature in spite of almost equal acidity for both Si atoms. This can be explained by the preference of 5- over 6-membered chelating ring systems. At higher temperatures the 1H NMR spectra show a fluctuation of the N-donor between the two Si centres.

scholarly journals Platelet Adhesion and Thrombus Formation in Microchannels: The Effect of Assay-Dependent Variables

2020 ◽  
Vol 21 (3) ◽  
pp. 750 ◽  
Author(s):  
Mariangela Scavone ◽  
Silvia Bozzi ◽  
Tatiana Mencarini ◽  
Gianmarco Podda ◽  
Marco Cattaneo ◽  
...  
Keyword(s):  
Room Temperature ◽  
Platelet Adhesion ◽  
Storage Temperature ◽  
Thrombus Formation ◽  
Antiplatelet Agent ◽  
Significant Inhibition ◽  
Type I ◽  
Collagen Concentration ◽  
A Value ◽  
Platelet Deposition

Microfluidic flow chambers (MFCs) allow the study of platelet adhesion and thrombus formation under flow, which may be influenced by several variables. We developed a new MFC, with which we tested the effects of different variables on the results of platelet deposition and thrombus formation on a collagen-coated surface. Methods: Whole blood was perfused in the MFC over collagen Type I for 4 min at different wall shear rates (WSR) and different concentrations of collagen-coating solutions, keeping blood samples at room temperature or 37 °C before starting the experiments. In addition, we tested the effects of the antiplatelet agent acetylsalicylic acid (ASA) (antagonist of cyclooxygenase-1, 100 µM) and cangrelor (antagonist of P2Y12, 1 µM). Results: Platelet deposition on collagen (I) was not affected by the storage temperature of the blood before perfusion (room temperature vs. 37 °C); (II) was dependent on a shear rate in the range between 300/s and 1700/s; and (III) was influenced by the collagen concentration used to coat the microchannels up to a value of 10 µg/mL. ASA and cangrelor did not cause statistically significant inhibition of platelet accumulation, except for ASA at low collagen concentrations. Conclusions: Platelet deposition on collagen-coated surfaces is a shear-dependent process, not influenced by the collagen concentration beyond a value of 10 µg/mL. However, the inhibitory effect of antiplatelet drugs is better observed using low concentrations of collagen.

Room temperature weak ferromagnetism in Mn doped CuI films

Vacuum ◽  
2019 ◽  
Vol 163 ◽  
pp. 317-323
Author(s):  
J. Ruby Jemima ◽  
S. Kalyanaraman ◽  
D.S. Ivan Jebakumar ◽  
R. Biju Bennie ◽  
R. Vettumperumal
Keyword(s):  
Room Temperature ◽  
Weak Ferromagnetism ◽  
Mn Doped

An Experimental Study of Carbon Nanotube Reinforcements

2011 ◽  
Author(s):  
Lauren Patrin ◽  
Frank Chow ◽  
Gabriela Philippart ◽  
Feridun Delale ◽  
Benjamin Liaw ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Young's Modulus ◽  
Testing Machine ◽  
Type I ◽  
Electrical Measurements ◽  
Standard Type ◽  
Reinforcement Percentage

Due to their high strength and stiffness carbon nanotubes (CNTs) have been considered as candidates for reinforcement of polymeric resins. It is also known that the addition of CNTs to polymeric matrix results in highly conductive nanocomposites, making the material multifunctional. Most of the CNT reinforced polymeric nanocomposite systems reported in the literature have been studied at room temperature. However, in many applications, materials may be subjected from low to elevated temperatures. Thus, the aim of this research is to study CNT reinforced polypropylene (PP) specimens at room, elevated and low temperatures. ASTM standard Type I specimens manufactured via injection molding and reinforced with 0.2%, 1%, 3%, and 6% CNTs were first subjected to tensile loads in a universal testing machine at room temperature. Neat PP resin specimens were also tested to provide baseline data. The tests were repeated at −54°C (−65°F), −20°C (−4°F), 49°C (120°F) and 71°C (160°F). The results were plotted as stress-strain curves and analyzed to delineate the effect of CNT reinforcement percentage and temperature on the mechanical properties. It was noted that as the percentage of CNT reinforcement increases, the resulting nanocomposite becomes stiffer (higher Young’s modulus), has higher strength and becomes more brittle. Temperature has a drastic effect on the behavior of the nanocomposite. As the temperature increases, at a given reinforcement percentage the material becomes more ductile with significantly lower Young’s modulus and strength compared to room temperature. At lower temperatures, the nanocomposite becomes more brittle with higher stiffness and strength, but significantly reduced failure strain. Also electrical measurements were conducted on the specimens to measure their resistance. For specimens reinforced with up to 3% of CNTs no electrical conductivity was detected. As expected at 6% CNT reinforcement (which is above the approximately 4% percolation limit reported in the literature), the specimens became electrically conductive. To predict the mechanical properties obtained experimentally, a micromechanics based model is presented and compared with the experimental results.

Comparison of the crystallographic and magnetic properties between Tb2Fe16.46Cr1.23 and Tb3(Fe,Cr)29 single crystals

1999 ◽  
Vol 14 (11) ◽  
pp. 4195-4199
Author(s):  
C. P. Yang ◽  
Y. Z. Wang ◽  
G. H. Wu ◽  
B. P. Hu ◽  
X. F. Han ◽  
...  
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Easy Axis ◽  
Magnetocrystalline Anisotropy ◽  
Czochralski Method ◽  
Type Structure ◽  
Type I ◽  
First Order ◽  
Magnetization Behavior ◽  
Curie Temperatures

A novel Tb3(Fe,Cr)29 single crystal, which has a monoclinic Nd3(Fe,Ti)29-type structure, is obtained using the Czochralski method by performing a proper heat treatment on the Tb2Fe16.46Cr1.23 crystal with a Th2Ni17-type structure. Thermomagnetic curves along the easy axis and magnetization curves along the easy and hard axes are presented for both crystals. The lattice parameters are a = 1.058 nm, b = 0.848 nm, c = 0.968 nm, α = γ = 90°, and β = 96.93° for the Tb3(Fe,Cr)29 single crystal. The Curie temperatures, saturation magnetizations, and magnetocrystalline anisotropy constants are compared between the Tb-2:17 and Tb-3:29 crystals. The magnetization behavior along the hard axis is quite different as a first-order magnetization process (FOMP) of type I for the Tb-2:17, but a FOMP of type II for the Tb-3:29 crystal is observed below room temperature. At low temperatures, magnetohistory effects are detected for both crystals.

Room-temperature weak ferromagnetism of amorphous HfAlOx thin films deposited by pulsed laser deposition

2006 ◽  
Vol 89 (24) ◽  
pp. 242504 ◽  
Author(s):  
X. Y. Qiu ◽  
Q. M. Liu ◽  
F. Gao ◽  
L. Y. Lu ◽  
J.-M. Liu
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Weak Ferromagnetism ◽  
Laser Deposition

Ge Nanoclusters in GeO2: Synthesis and Optical Properties

2005 ◽  
Vol 108-109 ◽  
pp. 83-90 ◽  
Author(s):  
Vladimir A. Volodin ◽  
E.B. Gorokhov ◽  
D.V. Marin ◽  
A.G. Cherkov ◽  
Anton K. Gutakovskii ◽  
...  
Keyword(s):  
Room Temperature ◽  
Blue Shift ◽  
High Resolution Electron Microscopy ◽  
Film Deposition ◽  
Germanium Oxide ◽  
Type I ◽  
Heterophase System ◽  
Raman Scattering Spectroscopy ◽  
Quantum Size ◽  
Resolution Electron

Ge nanocrystals (NCs) in GeO2 films obtained with the use of two methods were studied. The first method is a film deposition from supersaturated GeO vapor with subsequent dissociation of metastable GeO on heterophase system Ge:GeO2. The second method is growth of anomalous thick native germanium oxide layers with chemical composition GeOx(H2O) during catalytically enhanced Ge oxidation. The obtained films were studied with the use of photoluminescence (PL), Raman scattering spectroscopy, high-resolution electron microscopy (HREM). Strong PL signals were detected in GeO2 films with Ge-NCs at room temperature. “Blue-shift” of PL maximum was observed with reducing of Ge excess in anomalous thick native germanium oxide films. Also a correlation between reducing of the NC sizes (estimated from position of Raman peaks) and PL “blue-shift” was observed. The Ge NCs presence was confirmed by HREM data. The optical gap in Ge-NCs was calculated with taking into account quantum size effects and compared with the position of the experimental PL peaks. It can be concluded that a Ge-NC in GeO2 matrix is a quantum dot of type I.

Dielectric, ferroelectric, and ferromagnetic properties of 0.7Bi1−xLax(Fe0.9Cr0.1)O3–0.1BaTiO3–0.2PbTiO3 solid solutions

2010 ◽  
Vol 25 (9) ◽  
pp. 1812-1816 ◽  
Author(s):  
Xiao-hui Liu ◽  
Zhuo Xu ◽  
Xiao-yong Wei ◽  
Xi Yao
Keyword(s):  
Solid Solutions ◽  
Room Temperature ◽  
Hysteresis Loops ◽  
Weak Ferromagnetism ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Crystal Lattices ◽  
Temperature Polarization ◽  
Polarization Electric Field ◽  
Ferroelectric Hysteresis

Solid solutions 0.7Bi1−xLax (Fe0.9Cr0.1) O3–0.1BaTiO3–0.2PbTiO3 (BLxFOC-BT-PT, with x = 0, 0.03, 0.05, 0.07) solid solutions were prepared by the traditional ceramic process. X-ray diffraction results reveal that all samples show pure pseudocubic perovskites structure. The lattice parameter of the solid solutions increases linearly with the La content, indicating that La ions have entered crystal lattices to form a solid solution. The Curie temperature of the solid solutions decreases with the La content. Room-temperature polarization–electric field (P–E) curves indicate that the samples with x = 0.03 and 0.05 exhibit saturated P–E loops. Piezoelectric constant d33 of the solid solutions increases firstly and then decreases. Magnetizations of the solid solutions decrease with the La content. The evidence of weak ferromagnetism and saturated ferroelectric hysteresis loops in BLxFOC–BT–PT system at room temperature makes it a good candidate for multiferroic applications.

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