Modulated Structure of η´-Cu<sub>3+x</sub>(Si,Ge) Determined by Quantitative Electron Diffraction Tomography

Palatinus, Lukáš; Klementová, Mariana; Dřı́nek, Vladislav; Jarošová, Markéta; Petřı́ček, V.

doi:10.1017/s1431927611006404

Cited by 10 publications

(20 citation statements)

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“…The occupancies of the atoms in layer B were refined freely and the refinement resulted in a total composition of Cu 76.74 Si 23.26 , which is close to the expected compo-research papers sition Cu 76 Si 24 . The average structure is similar, but not identical, to the average structure of 0 -Cu 3+x Si as described by Palatinus et al (2011). For a discussion on the relationship between the two structures, see x4.3.…”

Section: Average Structuresupporting

confidence: 54%

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Crystal structures of η′′-Cu_3+xSi and η′′′-Cu_3+xSi

Corrêa¹,

Pérez²,

Kopeček³

et al. 2017

Acta Crystallogr Sect B

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The binary phase diagram of Cu-Si is unexpectedly complex in the vicinity of CuSi. The low-temperature region contains three closely related incommensurately modulated phases denoted, in order of increasing temperature of stability, η''', η'' and η'. The structure analysis of η' has been reported previously [Palatinus et al. (2011). Inorg. Chem. 50, 3743]. Here the structure model for the phases η'' and η''' is reported. The structures could be solved in superspace, but no superspace structure model could be constructed due to the complexity of the modulation functions. Therefore, the structures were described in a supercell approximation, which involved a 4 × 4 × 3 supercell for the η'' phase and a 14 × 14 × 3 supercell for the η''' phase. Both structures are very similar and differ only by a subtle symmetry lowering from η'' to η'''. A comparison of the structure models of η'' and η''' with the reported structure of η' suggests that the reported structure model of η' contains an incorrect assignment of atomic types.

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Section: Average Structuresupporting

confidence: 54%

“…Transformation to 00 was not observed. Palatinus et al (2011) investigated nanoplatelets of Cu 3+x (Si,Ge) using electron diffraction tomography. The phase was identified as the 0 phase.…”

Section: Introductionmentioning

confidence: 99%

Crystal structures of η′′-Cu_3+xSi and η′′′-Cu_3+xSi

Corrêa¹,

Pérez²,

Kopeček³

et al. 2017

Acta Crystallogr Sect B

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“…The data processing for dynamical refinement from EDT data is very similar to the procedure described for EDT data previously (Kolb et al, 2007(Kolb et al, , 2008Palatinus et al, 2011). It involves the following steps:…”

Section: Data Processing and Intensity Extractionmentioning

confidence: 99%

Structure refinement using precession electron diffraction tomography and dynamical diffraction: theory and implementation

2015

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Accurate structure refinement from electron-diffraction data is not possible without taking the dynamical-diffraction effects into account. A complete three-dimensional model of the structure can be obtained only from a sufficiently complete three-dimensional data set. In this work a method is presented for crystal structure refinement from the data obtained by electron diffraction tomography, possibly combined with precession electron diffraction. The principle of the method is identical to that used in X-ray crystallography: data are collected in a series of small tilt steps around a rotation axis, then intensities are integrated and the structure is optimized by least-squares refinement against the integrated intensities. In the dynamical theory of diffraction, the reflection intensities exhibit a complicated relationship to the orientation and thickness of the crystal as well as to structure factors of other reflections. This complication requires the introduction of several special parameters in the procedure. The method was implemented in the freely available crystallographic computing system Jana2006.

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“…The in-zone axis orientations are generally avoided because they are most affected by dynamic diffraction effects (Gorelik et al, 2011;Kolb et al, 2011). This results in three-dimensional electron diffraction data with a high coverage of the reciprocal space, which can be used for the solution of a modulated structure employing the charge flipping algorithm in superspace (Palatinus, 2004;Palatinus et al, 2011;Boullay et al, 2013). The obtained distribution of the scattering density can subsequently be used for introducing discontinuous occupancy modulations and building a model for the Rietveld refinement from XPD data (Boullay et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Synergy between transmission electron microscopy and powder diffraction: application to modulated structures

Batuk

Abakumov

et al. 2015

Acta Crystallogr Sect B

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The crystal structure solution of modulated compounds is often very challenging, even using the well established methodology of single-crystal X-ray crystallography. This task becomes even more difficult for materials that cannot be prepared in a single-crystal form, so that only polycrystalline powders are available. This paper illustrates that the combined application of transmission electron microscopy (TEM) and powder diffraction is a possible solution to the problem. Using examples of anion-deficient perovskites modulated by periodic crystallographic shear planes, it is demonstrated what kind of local structural information can be obtained using various TEM techniques and how this information can be implemented in the crystal structure refinement against the powder diffraction data. The following TEM methods are discussed: electron diffraction (selected area electron diffraction, precession electron diffraction), imaging (conventional high-resolution TEM imaging, high-angle annular dark-field and annular bright-field scanning transmission electron microscopy) and state-of-the-art spectroscopic techniques (atomic resolution mapping using energy-dispersive X-ray analysis and electron energy loss spectroscopy).

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Modulated Structure of η´-Cu_3+x(Si,Ge) Determined by Quantitative Electron Diffraction Tomography

Abstract: Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Cited by 10 publications

References 0 publications

Crystal structures of η′′-Cu_3+xSi and η′′′-Cu_3+xSi

Crystal structures of η′′-Cu_3+xSi and η′′′-Cu_3+xSi

Structure refinement using precession electron diffraction tomography and dynamical diffraction: theory and implementation

Synergy between transmission electron microscopy and powder diffraction: application to modulated structures

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Modulated Structure of η´-Cu3+x(Si,Ge) Determined by Quantitative Electron Diffraction Tomography

Abstract: Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Cited by 10 publications

References 0 publications

Crystal structures of η′′-Cu3+xSi and η′′′-Cu3+xSi

Crystal structures of η′′-Cu3+xSi and η′′′-Cu3+xSi

Structure refinement using precession electron diffraction tomography and dynamical diffraction: theory and implementation

Synergy between transmission electron microscopy and powder diffraction: application to modulated structures

Contact Info

Product

Resources

About

Modulated Structure of η´-Cu_3+x(Si,Ge) Determined by Quantitative Electron Diffraction Tomography

Crystal structures of η′′-Cu_3+xSi and η′′′-Cu_3+xSi

Crystal structures of η′′-Cu_3+xSi and η′′′-Cu_3+xSi