scholarly journals Application of focused-beam flat-sample method to synchrotron powder X-ray diffraction with anomalous scattering effect

2013 ◽  
Vol 425 (13) ◽  
pp. 132018 ◽  
Author(s):  
M Tanaka ◽  
Y Katsuya ◽  
Y Matsushita
Keyword(s):  
Anomalous Scattering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scattering Effect ◽  
Flat Sample ◽  
Sample Method ◽  
Focused Beam

The Structure of a Zn(II) Metaphosphate Glass. I. The Cation Coordination by a Combination of X-Ray and Neutron Diffraction, EXAFS and X-Ray Anomalous Scattering

1996 ◽  
Vol 51 (12) ◽  
pp. 1209-1215 ◽  
Author(s):  
M. Bionducci ◽  
G. Licheri ◽  
A. Musinu ◽  
G. Navarra ◽  
G. Piccaluga ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Anomalous Scattering ◽  
Extended Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Preparation Conditions ◽  
Zinc Coordination ◽  
Cation Coordination ◽  
X Ray Absorption ◽  
Zn Ions

Abstract In order to clarify the reason of some discrepancies existing in literature, the zinc coordination in a Zn metaphosphate glass has been investigated by the complementary use of X-Ray Diffraction, Neutron Diffraction, Extended X-ray Absorption Fine Structure Spectroscopy and X-Ray Anoma-lous Scattering. All the techniques indicate a tetrahedral coordination of O atoms around Zn :+ ions, the Zn-O distance being 1.94 ± 0.01 Å. The simultaneous modelling of all the experimental data by Reverse Monte Carlo technique demonstrated that this coordination is consistent with an extended model in which metal ions are interposed between phosphate chains. The importance of describing the preparation conditions of the glasses is stressed when structural results have to be compared.

A SURFACE ANOMALOUS DIFFRACTION STUDY OF THE Ni(100)(3×3)-(Cs+O) SYSTEM

1999 ◽  
Vol 06 (05) ◽  
pp. 847-850 ◽  
Author(s):  
A. G. NORRIS ◽  
C. A. LUCAS ◽  
R. McGRATH ◽  
F. SCHEDIN ◽  
G. THORNTON ◽  
...  
Keyword(s):  
Fractional Order ◽  
Anomalous Scattering ◽  
Nickel Surface ◽  
Structural Determination ◽  
Nickel Substrate ◽  
X Ray Diffraction ◽  
Diffraction Intensity ◽  
Surface Layers ◽  
X Ray ◽  
Intensity Measurements

Alkali metal coadsorption systems represent a step along the pathway from simple model adsorbate overlayers to more technologically relevant real systems. However, such is their complexity that very few systems have been structurally determined. Here we present a surface X-ray diffraction investigation of one of these systems, Ni (100)-(3×3)- (Cs+O) . Here a structural determination is particularly challenging due to the presence of three species in the surface layers and by the size of the unit cell. As a first step, anomalous scattering has been used to determine whether there is a contribution of the nickel substrate to the fractional order diffraction intensity. Measurements of the fractional order rods at 10 eV and 200 V below the nickel K edge (8333 eV) were used to probe the nickel contribution to the fractional order rods. It was found that the intensity of the scattering was unchanged, indicating that the fractional order peaks are caused by scattering from the coadsorbates only. This shows that the nickel surface layers are not changed by the adsorption and thus sets a useful constraint on the number of possible structures.

scholarly journals Cation disorder in CZTS materials from anomalous diffraction at KMC-2 (BESSY)

2014 ◽  
Vol 70 (a1) ◽  
pp. C1774-C1774
Author(s):  
Daniel Többens ◽  
Kai Neldner ◽  
Laura Valle-Rios ◽  
Susan Schorr
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Grazing Incidence ◽  
Thin Film Solar Cells ◽  
Anomalous Scattering ◽  
X Ray Diffraction ◽  
Promising Alternative ◽  
X Ray ◽  
Cu And Zn ◽  
Absorption Edges

The compound semiconductor Cu2ZnSnS4 (CZTS) is a promising alternative for absorber layers in thin film solar cells, as it has a nearly ideal band gap of about 1.5 eV, a high absorption coefficient for visible light, and contains only earth abundant and non-toxic elements. Besides chemical composition and phase purity, the efficiency of CZTS thin film solar cells depends strongly on the concentration of Cu- and Zn-antisites and copper vacancies in the kesterite-type structure. However, Cu(I) and Zn(II) are isoelectric and thus cannot be distinguished by conventional X-ray diffraction. In prior work we determined Cu-Zn-distribution successfully from neutron scattering [1]. Here we present experiments utilizing anomalous X-ray diffraction on the K-edges of Cu and Zn. Anomalous scattering coefficients are heavily wavelength-dependent close to the absorption edges of the respective element. This is utilized for contrast enhancement. Usage of multiple wavelengths above, below and between the absorption edges of Cu and Zn ensures significant overdetermination, so that the Cu-, Zn-, and vacancy concentrations can be refined reliably for the independent crystallographic sites. Experiments were conducted at the diffraction end station of the KMC-2 beamline [2] at BESSY (Berlin, Germany). KMC-2 provides X-ray radiation with both very stable energies and intensities. The accessible energy range of 4 – 14 keV is ideally suited for the K-edges of Cu (8979 eV) and Zn (9659 eV). A 6-circle goniometer in psi-geometry allows both powder and grazing incidence diffraction, so that bulk samples and thin films can be measured. The instrument can be equipped with either a scintillation point detector (Cyberstar) or an area detector (Bruker Vantec), allowing to optimize resolution and intensity to the needs of the experiment.

Quantitative phase analysis in the Ti–Al–C ternary system by X-ray diffraction

2005 ◽  
Vol 20 (3) ◽  
pp. 218-223 ◽  
Author(s):  
Chang-An Wang ◽  
Aiguo Zhou ◽  
Liang Qi ◽  
Yong Huang
Keyword(s):  
Ternary System ◽  
Phase Analysis ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
Internal Standards ◽  
X Ray ◽  
Quantitative Phase ◽  
Diffraction Peaks ◽  
Equation Group ◽  
Sample Method

Materials in the Ti–Al–C ternary system commonly contain three coexisting phases, Ti3AlC2, Ti2AlC, and TiC. Quantitative phase analysis in this ternary system was investigated using X-ray diffraction. First, nonoverlap diffraction peaks were selected: the (002) peak at 2θ=9.5° for Ti3AlC2 (I∕I0=26.5), the (002) peak at 2θ=13.0° for Ti2AlC (I∕I0=39), and the (111) peak at 2θ=35.9° for TiC (I∕I0=78), respectively. Then, based on the mixing-sample method without internal standards, a set of equations was derived for determining the amounts of Ti3AlC2, Ti2AlC, and TiC in a sample using the intensities of the selected diffraction peaks. Finally, the applicability and error sources for this method were investigated. The method is simple and straightforward, and is applicable to the entire Ti–Al–C ternary system, since the derivation of this equation group is self-checking.

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