Synthesis and Structure of Novel A2BO5 Compounds Containing A = Y, Yb, Gd, Sm, and La and B = Zr, Ti, and Sn

MRS Advances ◽  
2018 ◽  
Vol 3 (20) ◽  
pp. 1117-1122 ◽  
Author(s):  
R. Newman ◽  
R.D. Aughterson ◽  
G.R. Lumpkin

With the aim of creating novel ceramics for applications in nuclear materials with high radiation tolerance, multiple samples with A-B-O stoichiometries ranging from 215 to 227 were synthesized and characterized by a combination of SEM, XRD, and TEM methods. Single-phase defect-fluorite-type compounds with A = Sm or Yb and B = Ti, Zr, and/or Sn are reported; whereas, pyrochlore structured compounds and lanthanide sesquioxide phases were found as major phases in numerous samples. A series of Y-b-Sn-O samples was successfully prepared as nearly single phase or single phase materials. These are essentially defect fluorites with extra weak peaks, most likely due to X-ray scattering from oxygen or oxygen and metal cations. We describe some interesting TEM data and describe selected area diffraction patterns with complex modulations.

2017 ◽  
Vol 50 (3) ◽  
pp. 951-958 ◽  
Author(s):  
Sen Chen ◽  
Juncheng E ◽  
Sheng-Nian Luo

SLADS(http://www.pims.ac.cn/Resources.html), a parallel code for direct simulations of X-ray scattering of large anisotropic dense nanoparticle systems of arbitrary species and atomic configurations, is presented. Particles can be of arbitrary shapes and dispersities, and interactions between particles are considered. Parallelization is achieved in real space for the sake of memory limitation. The system sizes attempted are up to one billion atoms, and particle concentrations in dense systems up to 0.36. Anisotropy is explored in terms of superlattices. One- and two-dimensional small-angle scattering or diffraction patterns are obtained.SLADSis validated self-consistently or against cases with analytical solutions.


2012 ◽  
Vol 29 (1) ◽  
pp. 50
Author(s):  
D.N Ba ◽  
L.T Tai ◽  
N.T Trung ◽  
N.T Huy

The influences of the substitution of Ni with Mg on crystallographic and magnetic properties of the intermetallic alloys LaNi5-xMgx (x ≤ 0.4) were investigated. The X-ray diffraction patterns showed that all samples were of single phase, and the lattice parameters, a and c, decreased slightly upon chemical doping. LaNi5 is well known as an exchange-enhanced Pauli paramagnet. Interestingly, in LaNi5-xMgx, the ferromagnetic order existed even with a small amount of dopants; the Curie temperature reached the value of room temperature for x = 0.2, and enhanced with increasing x.


1997 ◽  
Vol 30 (1) ◽  
pp. 16-20 ◽  
Author(s):  
A. Gibaud ◽  
D. Harlow ◽  
J. B. Hastings ◽  
J. P. Hill ◽  
D. Chapman

The technique of high-energy monochromatic Laue X-ray scattering using image plates to record the diffraction patterns is presented. A tunable wiggler beamline is used as an X-ray source. It is shown that such experimental conditions present many advantages over conventional tube sources and photographic films. A study of diffuse scattering in the perovskite compound KMnF3 is presented to illustrate this in a qualitative way.


2007 ◽  
Vol 63 (4) ◽  
pp. 663-673 ◽  
Author(s):  
Lynne H. Thomas ◽  
T. Richard Welberry ◽  
Darren J. Goossens ◽  
Aidan P. Heerdegen ◽  
Matthias J. Gutmann ◽  
...  

Monte Carlo computer simulation has been used to interpret and model observed single-crystal diffuse X-ray scattering data for pentachloronitrobenzene, C6Cl5NO2. Each site in the crystal contains a molecule in one of six different basic orientations with equal probability. However, no short-range order amongst these different orientations has been detected. The strong, detailed and very distinctive diffraction patterns can be accounted for almost entirely on the assumption of random occupancy of each molecular site, but with very large local relaxation displacements that tend to increase the neighbouring distances for contacts involving NO2...NO2 and NO2...Cl with a corresponding reduction for those involving Cl...Cl. The results show that the mean NO2...NO2 distance is increased by ∼ 0.6 Å, compared with that given by the average structure determination.


1998 ◽  
Vol 4 (S2) ◽  
pp. 342-343 ◽  
Author(s):  
S. D. Walck ◽  
P. Ruzakowski-Athey

The analysis of Selected Area Diffraction (SAD) patterns that are collected from a single phase material having sufficient crystallites to provide continuous rings is relatively straightforward. However, when this condition is not met and there may be several phases present having rings of a spotty nature, the pattern is complex and can be quite difficult to analyze manually because of the vast number of discrete spots. WinJade from MDI is an X-ray diffraction (XRD) analysis program with an Electron Diffraction Program Module (EDPM) that can be used to aid in the analysis of SAD patterns. The EDPM produces Integrated Circular Density Plots (ICDP), which are one-dimensional intensity profiles plotted as a function of equivalent XRD 20 values or crystal d-spacings. These ICDP's can be overlayed with XRD patterns or with reference lines from the NIST and JCPDS crystalline databases for direct comparisons.


Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1198
Author(s):  
Li Li ◽  
Leyun Wang ◽  
Jie Wang ◽  
Huan Zhang ◽  
Qingchun Zhu ◽  
...  

In this study, in situ synchrotron X-ray experiments with wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS) detectors were performed on two pure magnesium materials produced by powder metallurgy. According to SAXS analysis, each of the two materials has a porosity of less than 0.5%. Line broadening analysis was performed on diffraction patterns collected by WAXS to analyze the dislocation evolution during material deformation. In both materials, <a>-type dislocation activities dominate the tensile deformation. The influence of grain size and texture on the different tensile behaviors of these two materials is also discussed.


2013 ◽  
Vol 67 (7) ◽  
pp. 1434-1441 ◽  
Author(s):  
Chiung-Fen Chang ◽  
I.-Peng Tseng

Magnetic TiO2 (MT) composites were prepared and applied to degrading phenol, which is one of the listed priority pollutants. The effects of heat treatment under preparation on the photocatalytic activity of MT composites have been investigated by varying the soaking time under a constant final temperature of 823 K. The total organic carbon and ring-remaining intermediates of o-DHB, p-DHB and 1,4-BQ in solution were detected during the photodegradation of phenol. All the resulting MT composites were the single-phase anatase and magnetite judged by X-ray diffraction patterns. The calcination of the as-prepared particles was proven to be extremely crucial to the photocatalytic activity. The best condition of heat treatment was found to be soaking time of 2 h at T = 823 K due to the good performance of photocatalytic activity, stable magnetic property, and reusability over three times. The results lead to the conclusion that recyclable MT composites prepared in this study, which belonged to the category of recyclable green materials, exhibit good photocatalytic activity to degrade phenol so as to possess applicable potential for the degradation of refractory organics in the aqueous solution. Furthermore, the environmental and health impacts were reduced as MT composites were applied in the treatment of water pollution.


1990 ◽  
Vol 5 (2) ◽  
pp. 61-63
Author(s):  
Ben Post ◽  
W. Frank McClune

The usefulness of an X-ray powder diffraction data base, such as the one published by the International Centre for Diffraction Data, is largely dependent on continued additions of indexed powder patterns of single-phase materials of interest to data-base users. The single-phase character of a specimen is generally established by using known values of the unit cell constants to index all its powder pattern lines.In this manuscript we describe indexing procedures based on crystal data which provide only relative values of the cell dimensions, rather than the absolute values usually considered to be essential to the indexing process. To the best of our knowledge, the use of such data for indexing powder diffraction patterns has generally been overlooked or ignored by X-ray crystallographers. We refer to the large numbers of goniometric measurements of crystals which have been published both before, and since, the discovery of X-ray diffraction. These provide useful descriptions of chemical and physical properties of crystals as well as measurements of relative dimensions of unit cell axes. The latter are presented in the form of a/b, b/b and c/b, together with the interaxial angle or angles, if the cell is nonorthogonal.


1989 ◽  
Vol 03 (16) ◽  
pp. 1221-1224 ◽  
Author(s):  
H. S. CAMPOS ◽  
W. A. KELLER

We have developed a self-consistent X-ray scattering model for perfect crystal, which leads to obtain diffraction patterns similar to experimental findings. As an application of the model we carried out the calculations for the Si[333] reflection curve.


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