Anisotropic strain in YBa2Cu3O7−δfilms analysed by deconvolution of two-dimensional intensity data

2001 ◽  
Vol 34 (1) ◽  
pp. 13-15
Author(s):  
J. Brötz ◽  
H. Fuess
Keyword(s):  
Superconducting Films ◽  
Reciprocal Space ◽  
Intensity Data ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Diffraction Intensity ◽  
X Ray ◽  
Anisotropic Strain ◽  
Crystalline Substrate ◽  
Instrumental Resolution

The influence of the instrumental resolution on two-dimensional reflection profiles of epitaxic YBa2Cu3O7−δfilms on SrTiO3(001) has been studied in order to investigate the strain in the superconducting films. The X-ray diffraction intensity data were obtained by two-dimensional scans in reciprocal space (q-scan). Since the reflection broadening caused by the apparatus differs for each position in reciprocal space, a highly crystalline substrate was used as a standard. Thus it was possible to measure a standard very close to the YBa2Cu3O7−δreflections in reciprocal space. The two-dimensional deconvolution of reflections by a new computer program revealed an anisotropic strain of the two twinning systems of the film.

scholarly journals Integration techniques for surface X-ray diffraction data obtained with a two-dimensional detector

2014 ◽  
Vol 47 (1) ◽  
pp. 365-377 ◽  
Author(s):  
Jakub Drnec ◽  
Tao Zhou ◽  
Stelian Pintea ◽  
Willem Onderwaater ◽  
Elias Vlieg ◽  
...  
Keyword(s):  
Reciprocal Space ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Integration Methods ◽  
X Ray ◽  
Structure Factors ◽  
Integration Techniques ◽  
Intensity Map ◽  
Integrated Intensities ◽  
Surface Diffraction

This article proposes two integration methods to determine the structure factors along a surface diffraction rod measured with a two-dimensional detector. The first method applies the classic way of calculating integrated intensities in angular space. This is adapted to work efficiently with two-dimensional data. The second method is based on integration in reciprocal space. An intensity map is created by converting the detected intensity pixel by pixel to the reciprocal space. The integration is then performed directly on this map. A theoretical framework, as well as a comparison between the two integration methods, is provided.

X-ray microbeam diffraction in a crystal

2021 ◽  
Vol 77 (2) ◽  
Author(s):  
Vasily I. Punegov ◽  
Andrey V. Karpov
Keyword(s):  
Geometrical Optics ◽  
Reciprocal Space ◽  
The Other ◽  
Angular Distributions ◽  
Scattered Intensity ◽  
Exit Slit ◽  
X Ray Diffraction ◽  
Diffraction Intensity ◽  
X Ray ◽  
Boundary Functions

Using the formalism of dynamical scattering of spatially restricted X-ray fields, the diffraction of a microbeam in a crystal with boundary functions for the incident and reflected amplitudes was studied in the case of geometrical optics and the Fresnel approximation (FA). It is shown that, for a wide front of the X-ray field, the angular distributions of the scattered intensity in the geometrical optics approximation (GOA) and the FA are approximately the same. On the other hand, it is established that, for a narrow exit slit in the diffraction scheme, it is always necessary to take into account the X-ray diffraction at the slit edges. Reciprocal-space maps and the distribution of the diffraction intensity of the microbeam inside the crystal were calculated.

New symmetry and structure for spinel

1983 ◽  
Vol 386 (1791) ◽  
pp. 333-345 ◽  
Keyword(s):  
Crystal Structure ◽  
Experimental Data ◽  
Physical Properties ◽  
Magnesium Aluminate ◽  
Intensity Data ◽  
Structure Parameter ◽  
X Ray Diffraction ◽  
Diffraction Intensity ◽  
X Ray ◽  
Structure Factors

The crystal structure of magnesium aluminate is conventionally described within a symmetry corresponding to the centrosymmetrical space group Fd3m but this has created difficulties for the interpretation of many of its physical properties. Therefore, extensive X-ray diffraction intensity data have been collected from a small spherical synthetic single crystal and used for a structure parameter refinement assuming F4̅3m symmetry as proposed by Grimes ( Phil. Mag . 26, 1217‒1226 (1972)), and also for refinement according to conventional symmetry. The F4̅3m assumption yields the first direct measurement of the suspected deviations from the centrosymmetrical structure, and is found to provide a significantly superior fit to the experimental data, especially at high angles and with reflexions having structure factors less than 10.0. The weak reflexions include nine that are forbidden under Fd3m symmetry and it is shown that there is satisfactory agreement between observed and calculated structure factors in these cases.

scholarly journals Indium Ammoniates from Ammonothermal Synthesis: InAlF6(NH3)2, [In(NH3)6][AlF6], and [In2F(NH3)10]2[SiF6]5 ∙ 2 NH3

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 679
Author(s):  
Peter Becker ◽  
Toni Boris Cekovski ◽  
Rainer Niewa
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Intensity Data ◽  
X Ray Diffraction ◽  
Diffraction Intensity ◽  
Crucible Material ◽  
Fluoride Ions ◽  
X Ray ◽  
Bonding Systems ◽  
Supercritical Ammonia

The ammonothermal synthesis of three ammoniates of indium, namely InAlF6(NH3)2, [In(NH3)6][AlF6], and [In2F(NH3)10]2[SiF6]5 ∙ 2 NH3 was successful from near-ammononeutral conditions in the presence of fluoride ions. Initially, all these compounds were obtained upon corrosion of the applied liner and crucible material Si3N4, which also contains small amounts of aluminum. The syntheses were performed in supercritical ammonia (T = 753 K, p up to 307 MPa). The crystal structures were solved and refined from single crystal X-ray diffraction intensity data. InAlF6(NH3)2 crystallizes as a typical layer-type structure with corner-sharing [InF4(NH3)2]– and [AlF6]3− octahedra. [In(NH3)6][AlF6] features isolated [In(NH3)6]3+ and [AlF6]3− octahedra. The crystal structure of [In2F(NH3)10]2[SiF6]5 ∙ 2 NH3 contains [(NH3)5In–F–In(NH3)5]5+ octahedra doubles next to [SiF6]2− octahedra and ammonia molecules. All intermediates have strong hydrogen bonding systems. The results from vibrational spectroscopy are reported.

An X-Ray Diffraction Study of the Phase Transformation Temperature of MnO

1965 ◽  
Vol 9 ◽  
pp. 152-158
Author(s):  
Charles P. Gazzara ◽  
R. M. Middleton
Keyword(s):  
Phase Transformation ◽  
Magnetic Transition ◽  
Phase Transformation Temperature ◽  
Intensity Data ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
Diffraction Intensity ◽  
Magnetic Transition Temperature ◽  
X Ray ◽  
Structural Temperature

AbstractX-Ray diffraction measurements of MnO confirm the hypothesis that the structural temperature and the magnetic transition temperature, or Néel temperature) are the same. The usefulness of X-ray diffraction intensity data of MnO, with respect to an atomic structural refinement problem involving α-Mn powders, is discussed. Lattice constant values of MnO are listed between 100 and 310°K

Angle calculations for a (2+3)-type diffractometer: focus on area detectors

2010 ◽  
Vol 44 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Christian M. Schlepütz ◽  
Simon O. Mariager ◽  
Stephan A. Pauli ◽  
Robert Feidenhans'l ◽  
Philip R. Willmott
Keyword(s):  
Direct Conversion ◽  
Reciprocal Space ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sample Configuration ◽  
Diffraction Signal

Angle calculations for a (2+3)-type diffractometer are presented with comprehensive derivations for both cases of either a vertical or horizontal sample configuration. This work focuses on some particular aspects of using area detectors in surface X-ray diffraction, namely the role of the detector rotation and the direct conversion of the angle-resolved diffraction signal recorded by the detector into a two-dimensional slice through reciprocal space.

Tubulin structure at intermediate resolution

1995 ◽  
Vol 53 ◽  
pp. 852-853
Author(s):  
K. H. Downing ◽  
S. G. Wolf ◽  
E. Nogales
Keyword(s):  
High Resolution ◽  
Structural Data ◽  
Therapeutic Drug ◽  
Zinc Ions ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Negative Stain ◽  
Functional Mechanisms ◽  
Tubulin Structure

Microtubules are involved in a host of critical cell activities, many of which involve transport of organelles through the cell. Different sets of microtubules appear to form during the cell cycle for different functions. Knowledge of the structure of tubulin will be necessary in order to understand the various functional mechanisms of microtubule assemble, disassembly, and interaction with other molecules, but tubulin has so far resisted crystallization for x-ray diffraction studies. Fortuitously, in the presence of zinc ions, tubulin also forms two-dimensional, crystalline sheets that are ideally suited for study by electron microscopy. We have refined procedures for forming the sheets and preparing them for EM, and have been able to obtain high-resolution structural data that sheds light on the formation and stabilization of microtubules, and even the interaction with a therapeutic drug.Tubulin sheets had been extensively studied in negative stain, demonstrating that the same protofilament structure was formed in the sheets and microtubules. For high resolution studies, we have found that the sheets embedded in either glucose or tannin diffract to around 3 Å.

Synthesis and Structure of a Clathrated Two-Dimensional Metal-Organic Framework: [Cd(4,4'-bpy)2(H2O)2](ClO4)2·(L)2·H2O (L = Bis(1-pyrazinylethylidene)hydrazine)

2008 ◽  
Vol 73 (1) ◽  
pp. 24-31
Author(s):  
Dayu Wu ◽  
Genhua Wu ◽  
Wei Huang ◽  
Zhuqing Wang
Keyword(s):  
Metal Organic Framework ◽  
Channel Structure ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
X Ray ◽  
Square Planar ◽  
Metal Organic ◽  
Aqueous Meoh ◽  
Organic Framework

The compound [Cd(4,4'-bpy)2(H2O)2](ClO4)2·(L)2 was obtained by the reaction of Cd(ClO4)2, bis(1-pyrazinylethylidene)hydrazine (L) and 4,4'-bipyridine in aqueous MeOH. Single-crystal X-ray diffraction has revealed its two-dimensional metal-organic framework. The 2-D layers superpose on each other, giving a channel structure. The square planar grids consist of two pairs of shared edges with Cd(II) ion and a 4,4'-bipyridine molecule each vertex and side, respectively. The square cavity has a dimension of 11.817 × 11.781 Å. Two guest molecules of bis(1-pyrazinylethylidene)hydrazine are clathrated in every hydrophobic host cavity, being further stabilized by π-π stacking and hydrogen bonding. The results suggest that the hydrazine molecules present in the network serve as structure-directing templates in the formation of crystal structures.

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