Strong 5f Ferromagnetism in UH3-Based Materials

MRS Advances ◽  
2016 ◽  
Vol 1 (44) ◽  
pp. 2987-2992 ◽  
Author(s):  
Ladislav Havela ◽  
Mykhaylo Paukov ◽  
Ilya Tkach ◽  
Volodymyr Buturlim ◽  
Zdenek Matej ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Distribution Function ◽  
Curie Temperature ◽  
Pair Distribution Function ◽  
High Energy ◽  
The Other ◽  
X Rays ◽  
Other Hand ◽  
Pdf Analysis

ABSTRACT Several diverse types of UH3-based hydrides can be prepared by hydrogenation of bcc U-based alloys. Pair Distribution Function (PDF) analysis using high-energy X-rays identified that the (UH3)1-x Mo x hydrides are nanocrystalline, with the structure motif based mainly on the β-UH3 structure. α-UH3 represents a minority component. On the other hand, PDF of the (UH3)1-x Zr x hydrides corresponds well to the α-UH3 crystal structure. All the hydrides are ferromagnetic, with the Curie temperature T C reaching up to 203 K.

scholarly journals Total-scattering pair-distribution function analysis of zinc from high-energy synchrotron data

2019 ◽  
Vol 33 (33) ◽  
pp. 1950410 ◽  
Author(s):  
Ahmad S. Masadeh ◽  
Moneeb T. M. Shatnawi ◽  
Ghosoun Adawi ◽  
Yang Ren
Keyword(s):  
Crystal Structure ◽  
Distribution Function ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
High Energy ◽  
Ambient Conditions ◽  
Total Scattering ◽  
X Ray ◽  
Zinc Metal ◽  
Pdf Analysis

The crystal structure of zinc metal deviates from the ideal hexagonal close packing structure by a significantly increased axial ratio (c/a). The local atomic structure of zinc metal is investigated using the total scattering atomic pair distribution function (PDF) analysis based on X-ray powder diffraction data collected at ambient conditions. The X-ray total scattering PDF analysis confirms that the crystal structure of zinc can be described in terms of wurtzite structure, but with an anomalously atomic displacement parameters [Formula: see text], indicating a significant displacement disorder along the [Formula: see text]-axis. For the long [Formula: see text]-range PDF refinements, the thermal motion of zinc shows a notable anisotropy as expressed by the ratio [Formula: see text]/[Formula: see text] of 2.5 at ambient conditions. This average distortion level along the [Formula: see text]-axis, was not reflected locally for the features below 5.0 Å as it fits the high [Formula: see text] region. Based on PDF refinements over different [Formula: see text]-ranges, we measure an interesting increase of the [Formula: see text] value with decreasing the [Formula: see text]-range of the refinement. This suggests that the local structure features in zinc metal differ from the average structure ones.

scholarly journals Rapid-acquisition pair distribution function (RA-PDF) analysis

2003 ◽  
Vol 36 (6) ◽  
pp. 1342-1347 ◽  
Author(s):  
Peter J. Chupas ◽  
Xiangyun Qiu ◽  
Jonathan C. Hanson ◽  
Peter L. Lee ◽  
Clare P. Grey ◽  
...  
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
High Energy ◽  
Data Sets ◽  
Crystalline Materials ◽  
Rapid Acquisition ◽  
Atomic Pair Distribution Function ◽  
Pdf Analysis ◽  
Diffraction Patterns ◽  
Counting Statistics

An image-plate (IP) detector coupled with high-energy synchrotron radiation was used for atomic pair distribution function (PDF) analysis, with high probed momentum transferQmax≤ 28.5 Å−1, from crystalline materials. Materials with different structural complexities were measured to test the validity of the quantitative data analysis. Experimental results are presented for crystalline Ni, crystalline α-AlF3, and the layered Aurivillius type oxides α-Bi4V2O11and γ-Bi4V1.7Ti0.3O10.85. Overall, the diffraction patterns show good counting statistics, with measuring time from one to tens of seconds. The PDFs obtained are of high quality. Structures may be refined from these PDFs, and the structural models are consistent with the published literature. Data sets from similar samples are highly reproducible.

scholarly journals Time-resolved pair distribution function analysis of disordered materials on beamlines BL04B2 and BL08W at SPring-8

2018 ◽  
Vol 25 (6) ◽  
pp. 1627-1633 ◽  
Author(s):  
Koji Ohara ◽  
Satoshi Tominaka ◽  
Hiroki Yamada ◽  
Masakuni Takahashi ◽  
Hiroshi Yamaguchi ◽  
...  
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Structural Changes ◽  
Function Analysis ◽  
Image Data ◽  
High Energy ◽  
Disordered Materials ◽  
X Rays ◽  
Two Dimensional ◽  
Time Resolved

A dedicated apparatus has been developed for studying structural changes in amorphous and disordered crystalline materials substantially in real time. The apparatus, which can be set up on beamlines BL04B2 and BL08W at SPring-8, mainly consists of a large two-dimensional flat-panel detector and high-energy X-rays, enabling total scattering measurements to be carried out for time-resolved pair distribution function (PDF) analysis in the temperature range from room temperature to 873 K at pressures of up to 20 bar. For successful time-resolved analysis, a newly developed program was used that can monitor and process two-dimensional image data simultaneously with the data collection. The use of time-resolved hardware and software is of great importance for obtaining a detailed understanding of the structural changes in disordered materials, as exemplified by the results of commissioned measurements carried out on both beamlines. Benchmark results obtained using amorphous silica and demonstration results for the observation of sulfide glass crystallization upon annealing are introduced.

scholarly journals PDF Analysis on a Laboratory System: Adapting the Experiment to the Material

2014 ◽  
Vol 70 (a1) ◽  
pp. C870-C870
Author(s):  
Céleste Reiss ◽  
Milen Gateshki ◽  
Marco Sommariva
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Amorphous Materials ◽  
Nearest Neighbors ◽  
High Energy ◽  
Experimental Point ◽  
Laboratory System ◽  
Crystalline Materials ◽  
X Ray ◽  
Pdf Analysis

The increased interest in recent years regarding the properties and applications of nanomaterials has also created the need to characterize the structures of these materials. However, due to the lack of long-range atomic ordering, the structures of nanostructured and amorphous materials are not accessible by conventional diffraction methods used to study crystalline materials. One of the most promising techniques to study nanostructures using X-ray diffraction is by using the total scattering (Bragg peaks and diffuse scattering) from the samples and the pair distribution function (PDF) analysis. The pair distribution function provides the probability of finding atoms separated by a certain distance. This function is not direction-dependent; it only looks at the absolute value of the distance between the nearest neighbors, the next nearest neighbors and so on. The method can therefore also be used to analyze non-crystalline materials. From experimental point of view a typical PDF analysis requires the use of intense high-energy X-ray radiation (E ≥ 20 KeV) and a wide 2θ range. After the initial feasibility studies regarding the use of standard laboratory diffraction equipment for PDF analysis [1-3] this application has been further developed to achieve improved data quality and to extend the range of materials, environmental conditions and geometrical configurations that can be used for PDF experiments. Studies performed on different nanocrystalline and amorphous materials of scientific and technological interest, including organic substances, oxides, metallic alloys, etc. have demonstrated that PDF analysis with a laboratory diffractometer can be a valuable tool for structural characterization of nanomaterials. This contribution presents several examples of laboratory PDF studies, in which the experimental conditions have been successfully adapted to match the specific requirements of materials under investigation.

scholarly journals On the interpretation of X-ray, single crystal, rotation photographs

1926 ◽  
Vol 113 (763) ◽  
pp. 117-160 ◽  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
The Other ◽  
X Rays ◽  
X Ray ◽  
Powder Method ◽  
Convenient Form ◽  
Other Hand ◽  
Rotation Method ◽  
Laue Method

In the development of the study of crystals by X-rays the methods used divide themselves naturally into four types : the Bragg Ionisation Spectrometer method, the Laue method, the Powder method of Debye and Scherrer, and the Rotating Crystal method of Rinne, Schiebold and Polyani. The techniques of the first three of these methods are fully explained in such books as ‘ X-Rays and Crystal Structure,’ by W. H. and W. L. Bragg, ‘ The Structure of Crystals,’ by Wyckoff, and ‘ Krystalle und Rontgenstrahlen,’ by Ewald, as well as in original papers. On the other hand, the rotation method is only slightly touched on in these works, the literature is scattered in a great number of papers, and the technique has not so far been described at any length in a convenient form. Particularly in English, references to it are scanty. In this paper the author has tried to give a concise account of the method, together with various types of charts and tables as it is used in the Davy Faraday Laboratory. The methods described differ in certain respects from those used on the Continent,* but they have been found to be rapid and sufficiently accurate.

scholarly journals Demonstration of thin film pair distribution function analysis (tfPDF) for the study of local structure in amorphous and crystalline thin films

IUCrJ ◽  
2015 ◽  
Vol 2 (5) ◽  
pp. 481-489 ◽  
Author(s):  
Kirsten M. Ø. Jensen ◽  
Anders B. Blichfeld ◽  
Sage R. Bauers ◽  
Suzannah R. Wood ◽  
Eric Dooryhée ◽  
...  
Keyword(s):  
Thin Films ◽  
Distribution Function ◽  
Structure Analysis ◽  
Local Structure ◽  
Pair Distribution Function ◽  
High Energy ◽  
Scattering Data ◽  
X Rays ◽  
Amorphous Precursor ◽  
Total Scattering

By means of normal-incidence, high-flux and high-energy X-rays, total scattering data for pair distribution function (PDF) analysis have been obtained from thin films (tf), suitable for local structure analysis. By using amorphous substrates as support for the films, the standard Rapid Acquisition PDF setup can be applied and the scattering signal from the film can be isolated from the total scattering data through subtraction of an independently measured background signal. No angular corrections to the data are needed, as would be the case for grazing incidence measurements. The `tfPDF' method is illustrated through studies of as-deposited (i.e.amorphous) and crystalline FeSb3films, where the local structure analysis gives insight into the stabilization of the metastable skutterudite FeSb3phase. The films were prepared by depositing ultra-thin alternating layers of Fe and Sb, which interdiffuse and after annealing crystallize to form the FeSb3structure. The tfPDF data show that the amorphous precursor phase consists of corner-sharing FeSb6octahedra with motifs highly resembling the local structure in crystalline FeSb3. Analysis of the amorphous structure allows the prediction of whether the final crystalline product will form the FeSb3phase with or without excess Sb present. The study thus illustrates how analysis of the local structure in amorphous precursor films can help to understand crystallization processes of metastable phases and opens for a range of new local structure studies of thin films.

scholarly journals Crystal Structure of Moganite and Its Anisotropic Atomic Displacement Parameters Determined by Synchrotron X-ray Diffraction and X-ray/Neutron Pair Distribution Function Analyses

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 272
Author(s):  
Seungyeol Lee ◽  
Huifang Xu ◽  
Hongwu Xu ◽  
Joerg Neuefeind
Keyword(s):  
Crystal Structure ◽  
Distribution Function ◽  
Single Crystal ◽  
Pair Distribution Function ◽  
Atomic Displacement ◽  
Single Crystal Xrd ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutron Pair ◽  
Atomic Displacement Parameters

The crystal structure of moganite from the Mogán formation on Gran Canaria has been re-investigated using high-resolution synchrotron X-ray diffraction (XRD) and X-ray/neutron pair distribution function (PDF) analyses. Our study for the first time reports the anisotropic atomic displacement parameters (ADPs) of a natural moganite. Rietveld analysis of synchrotron XRD data determined the crystal structure of moganite with the space group I2/a. The refined unit-cell parameters are a = 8.7363(8), b = 4.8688(5), c = 10.7203(9) Å, and β = 90.212(4)°. The ADPs of Si and O in moganite were obtained from X-ray and neutron PDF analyses. The shapes and orientations of the anisotropic ellipsoids determined from X-ray and neutron measurements are similar. The anisotropic ellipsoids for O extend along planes perpendicular to the Si-Si axis of corner-sharing SiO4 tetrahedra, suggesting precession-like movement. Neutron PDF result confirms the occurrence of OH over some of the tetrahedral sites. We postulate that moganite nanomineral is stable with respect to quartz in hypersaline water. The ADPs of moganite show a similar trend as those of quartz determined by single-crystal XRD. In short, the combined methods can provide high-quality structural parameters of moganite nanomineral, including its ADPs and extra OH position at the surface. This approach can be used as an alternative means for solving the structures of crystals that are not large enough for single-crystal XRD measurements, such as fine-grained and nanocrystalline minerals formed in various geological environments.

scholarly journals Improved Models for Metallic Nanoparticle Cores from Atomic Pair Distribution Function (PDF) Analysis

2018 ◽  
Vol 122 (51) ◽  
pp. 29498-29506 ◽  
Author(s):  
Soham Banerjee ◽  
Chia-Hao Liu ◽  
Jennifer D. Lee ◽  
Anton Kovyakh ◽  
Viktoria Grasmik ◽  
...  
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Metallic Nanoparticle ◽  
Atomic Pair Distribution Function ◽  
Atomic Pair ◽  
Pdf Analysis
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