Magneto-crystalline anisotropy in TbPdIn, DyNiAl and GdNiAl studied by using X-ray powder diffraction at low temperatures

2002 ◽  
Vol 345 (1-2) ◽  
pp. 10-15 ◽  
Author(s):  
S Daniš ◽  
P Javorský ◽  
D Rafaja
Keyword(s):  
Powder Diffraction ◽  
Low Temperatures ◽  
X Ray ◽  
Crystalline Anisotropy ◽  
Magneto Crystalline Anisotropy

scholarly journals Studies on Structural and Magnetic Properties in Co/Sm Multilayers

2012 ◽  
Vol 13 (1) ◽  
pp. 13
Author(s):  
Erwin Erwin
Keyword(s):  
Magnetic Properties ◽  
Multilayer Films ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
X Ray ◽  
Crystalline Anisotropy ◽  
Structural And Magnetic Properties ◽  
Sharp Interfaces ◽  
Magneto Crystalline Anisotropy

Co/Sm multilayer films with structure of 20 [Co (x nm)/Sm (1.2 nm)] where x = 1.1, 2.2 and 4.2 nm and 20[Co (4.2nm)/Sm (x nm)] where x=1.2 nm to 7.5 nm were fabricated using dc magnetron sputtering. Each multilayer filmconsisted of 20 bilayers of Co layers with various thicknesses sandwiched with Sm layers. The application of lowangle X-ray diffraction measurements to the characterization of these multilayers is described. The periodiclayered structure with sharp interfaces was observed for all multilayer films. The measured magnetization valuesare lower than the values calculated in terms of the nominal concentration of cobalt in the multilayers. This impliessignificant “mixing” at small film thickness. The formation of a high magneto crystalline anisotropy of CoSm alloyat the interfaces, as a result of interdiffusion between Co and Sm layers was considered to be responsible for theincrease of the coercivity for Co/Sm multilayer.

scholarly journals Rietveld refinement of the low temperature crystal structures of Cs2XSi5O12 (X = Cu, Cd and Zn)

2021 ◽  
Vol 12 (1) ◽  
pp. 60-63
Author(s):  
Anthony Martin Thomas Bell
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Low Temperature ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Low Temperatures ◽  
Powder Diffraction Data ◽  
Space Group ◽  
X Ray ◽  
Silicate Framework

The synthetic leucite silicate framework mineral analogues Cs2XSi5O12 (X = Cu, Cd, Zn) were prepared by high-temperature solid-state synthesis. The results of Rietveld refinement, using 18 keV synchrotron X-ray powder diffraction data collected at low temperatures (8K X = Cu, Zn; 10K X = Cd) show that the title compounds crystallize in the space group Pbca and are isostructural with the ambient temperature structures of these analogues. The structures consist of tetrahedrally coordinated SiO4 and XO4 sharing corners to form a partially substituted silicate framework. Extraframework Cs cations sit in channels in the framework. All atoms occupy the 8c general position for this space group. In these refined structures, silicon and X atoms are ordered onto separate tetrahedrally coordinated sites (T-sites).

New horizons for the structural characterization of stainless steel slags by X-ray powder diffraction

2007 ◽  
Vol 2007 (suppl_26) ◽  
pp. 61-66 ◽  
Author(s):  
B. Peplinski ◽  
B. Adamczyk ◽  
G. Kley ◽  
K. Adam ◽  
F. Emmerling ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Powder Diffraction ◽  
Structural Characterization ◽  
X Ray ◽  
New Horizons

X-ray Structure Refinement and Vibrational Spectroscopy of Ca8Gd2 (PO4)6 O2

2013 ◽  
Vol 12 (10) ◽  
pp. 719-726
Author(s):  
R. Ayadi ◽  
Mohamed Boujelbene ◽  
T. Mhiri
Keyword(s):  
Solid State ◽  
General Formula ◽  
Vibrational Spectroscopy ◽  
Powder Diffraction ◽  
Infrared Spectra ◽  
Solid State Reaction ◽  
Structure Refinement ◽  
Unit Cell ◽  
Cell Group ◽  
X Ray

The present paper is interested in the study of compounds from the apatite family with the general formula Ca10 (PO4)6A2. It particularly brings to light the exploitation of the distinctive stereochemistries of two Ca positions in apatite. In fact, Gd-Bearing oxyapatiteCa8 Gd2 (PO4)6O2 has been synthesized by solid state reaction and characterized by X-ray powder diffraction. The site occupancies of substituents is0.3333 in Gd and 0.3333 for Ca in the Ca(1) position and 0. 5 for Gd in the Ca (2) position.  Besides, the observed frequencies in the Raman and infrared spectra were explained and discussed on the basis of unit-cell group analyses.

Monitoring Polymer-Assisted Mechanochemical Cocrystallisation Through in Situ X-Ray Powder Diffraction

2020 ◽  
Author(s):  
Luzia S. Germann ◽  
Sebastian T. Emmerling ◽  
Manuel Wilke ◽  
Robert E. Dinnebier ◽  
Mariarosa Moneghini ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Powder Diffraction ◽  
Reaction Rate ◽  
Polymer Additives ◽  
Time Resolved ◽  
X Ray

Time-resolved mechanochemical cocrystallisation studies have so-far focused solely on neat and liquid-assisted grinding. Here, we report the monitoring of polymer-assisted grinding reactions using <i>in situ</i> X-ray powder diffraction, revealing that reaction rate is almost double compared to neat grinding and independent of the molecular weight and amount of used polymer additives.<br>

Crystal Transition and Drug-excipient Compatibility of Clarithromycin in Sustained Release Tablets

2020 ◽  
Vol 16 (7) ◽  
pp. 950-959
Author(s):  
Yu Li ◽  
Xiangwen Kong ◽  
Fan Hu
Keyword(s):  
Sustained Release ◽  
Powder Diffraction ◽  
Magnesium Stearate ◽  
Influential Factor ◽  
High Concentration ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Sustained Release Tablets ◽  
Crystal Transition ◽  
Excipient Compatibility

Background: Clarithromycin is widely used for infections of helicobacter pylori. Clarithromycin belongs to polymorphic drug. Crystalline state changes of clarithromycin in sustained release tablets were found. Objective: The aim of this study was to find the influential factor of the crystal transition of clarithromycin in preparation process of sustained-release tablets and to investigate the possible interactions between the clarithromycin and pharmaceutical excipients. Methods and Results: The crystal transition of active pharmaceuticals ingredients from form II to form I in portion in clarithromycin sustained release tablets were confirmed by x-ray powder diffraction. The techniques including differential scanning calorimetry and infrared spectroscopy, x-ray powder diffraction were used for assessing the compatibility between clarithromycin and several excipients as magnesium stearate, lactose, sodium carboxymethyl cellulose, polyvinyl-pyrrolidone K-30 and microcrystalline cellulose. All of these methods showed compatibilities between clarithromycin and the selected excipients. Alcohol prescription simulation was also done, which showed incompatibility between clarithromycin and concentration alcohol. Conclusion: It was confirmed that the reason for the incompatibility of clarithromycin with high concentration of alcohol was crystal transition.

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