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Journal of Applied Crystallography

Chenyang Shi
A new software program, xINTERPDF , that analyzes the intermolecular correlations in organic compounds via measured X-ray total scattering data is described.
October 1, 2018: Journal of Applied Crystallography
Grethe Vestergaard Jensen, John George Barker
In small-angle scattering theory and data modeling, it is generally assumed that each scattered ray - photon or neutron - is only scattered once on its path through the sample. This assumption greatly simplifies the interpretation of the data and is valid in many cases. However, it breaks down under conditions of high scattering power, increasing with sample concentration, scattering contrast, sample path length and ray wavelength. For samples with a significant scattering power, disregarding multiple scattering effects can lead to erroneous conclusions on the structure of the investigated sample...
October 1, 2018: Journal of Applied Crystallography
K Ian White, Valeria Bugris, Andrew A McCarthy, Raimond B G Ravelli, Krisztián Csankó, Alberto Cassetta, Sandor Brockhauser
The installation of multi-axis goniometers such as the ESRF/EMBL miniKappa goniometer system has allowed the increased use of sample reorientation in macromolecular crystallography. Old and newly appearing data collection methods require precision and accuracy in crystal reorientation. The proper use of such multi-axis systems has necessitated the development of rapid and easy to perform methods for establishing and evaluating device calibration. A new diffraction-based method meeting these criteria has been developed for the calibration of the motors responsible for rotational motion...
October 1, 2018: Journal of Applied Crystallography
V Lutz-Bueno, C Arboleda, L Leu, M J Blunt, A Busch, A Georgiadis, P Bertier, J Schmatz, Z Varga, P Villanueva-Perez, Z Wang, M Lebugle, C David, M Stampanoni, A Diaz, M Guizar-Sicairos, A Menzel
In most cases, the analysis of small-angle and wide-angle X-ray scattering (SAXS and WAXS, respectively) requires a theoretical model to describe the sample's scattering, complicating the interpretation of the scattering resulting from complex heterogeneous samples. This is the reason why, in general, the analysis of a large number of scattering patterns, such as are generated by time-resolved and scanning methods, remains challenging. Here, a model-free classification method to separate SAXS/WAXS signals on the basis of their inflection points is introduced and demonstrated...
October 1, 2018: Journal of Applied Crystallography
Hirotaka Yamaguchi, Akito Kuramata
Planar defects in -oriented β-Ga2 O3 wafers were studied using X-ray topography. These planar defects were rectangular with dimensions of 50-150 µm, and the X-ray topography analysis revealed that they were stacking faults (SFs) enclosed by a single partial dislocation loop on the plane. The SF formation was found to be supported by a unique structural feature of the plane as a slip plane; the plane consists of close-packed octahedral Ga and O layers, allowing slips to form SFs. Vacancy arrays along the b axis in the octahedral Ga layer reduce the self-energy of the edge component in the partial dislocation extending along the b axis...
October 1, 2018: Journal of Applied Crystallography
Ronald L Cappelletti, Terrence J Udovic, Hui Li, Rick L Paul
Commercial glassy carbon plates being used as absolute intensity calibration standards in small-angle X-ray scattering applications (NIST SRM 3600) have been characterized in several recent publications. This contribution adds to the characterization by measuring the hydrogen content of a plate to be (4.8 ± 0.2) × 10-4 (mol H)/(mol C), and by measuring the vibrational spectrum by neutron inelastic scattering. The spectrum bears a strong resemblance to published measurements on graphite, allowing the identification of several spectral features...
October 1, 2018: Journal of Applied Crystallography
Stef Smeets, Xiaodong Zou, Wei Wan
Serial electron crystallography has been developed as a fully automated method to collect diffraction data on polycrystalline materials using a transmission electron microscope. This enables useful data to be collected on materials that are sensitive to the electron beam and thus difficult to measure using the conventional methods that require long exposure of the same crystal. The data collection strategy combines goniometer translation with electron beam shift, which allows the entire sample stage to be probed...
October 1, 2018: Journal of Applied Crystallography
Stephen P Thompson, Hilary Kennedy, Sarah J Day, Annabelle R Baker, Benjamin M Butler, Emmal Safi, Jon Kelly, Andrew Male, Jonathan Potter, Tom Cobb, Claire A Murray, Chiu C Tang, Aneurin Evans, Ronaldo Mercado
Liquid oceans and ice caps, along with ice crusts, have long been considered defining features of the Earth, but space missions and observations have shown that they are in fact common features among many of the solar system's outer planets and their satellites. Interactions with rock-forming materials have produced saline oceans not dissimilar in many respects to those on Earth, where mineral precipitation within frozen seawater plays a significant role in both determining global properties and regulating the environment in which a complex ecosystem of extremophiles exists...
August 1, 2018: Journal of Applied Crystallography
Fermin Otálora, A Mazurier, J M Garcia-Ruiz, M J Van Kranendonk, E Kotopoulou, A El Albani, C J Garrido
Crystallography has a long history of providing knowledge and methods for applications in other disciplines. The identification of minerals using X-ray diffraction is one of the most important contributions of crystallography to earth sciences. However, when the crystal itself has been dissolved, replaced or deeply modified during the geological history of the rocks, diffraction information is not available. Instead, the morphology of the crystal cast provides the only crystallographic information on the original mineral phase and the environment of crystal growth...
August 1, 2018: Journal of Applied Crystallography
Ryan C Hurley, Eric B Herbold, Darren C Pagan
Three-dimensional X-ray diffraction (3DXRD), a method for quantifying the position, orientation and elastic strain of large ensembles of single crystals, has recently emerged as an important tool for studying the mechanical response of granular materials during compaction. Applications have demonstrated the utility of 3DXRD and X-ray computed tomography (XRCT) for assessing strains, particle stresses and orientations, inter-particle contacts and forces, particle fracture mechanics, and porosity evolution in situ ...
August 1, 2018: Journal of Applied Crystallography
Bärbel Krause, Dmitry S Kuznetsov, Andrey E Yakshin, Shyjumon Ibrahimkutty, Tilo Baumbach, Fred Bijkerk
Lanthanum and lanthanum nitride thin films were deposited by magnetron sputtering onto silicon wafers covered by natural oxide. In situ and real-time synchrotron radiation experiments during deposition reveal that lanthanum crystallizes in the face-centred cubic bulk phase. Lanthanum nitride, however, does not form the expected NaCl structure but crystallizes in the theoretically predicted metastable wurtzite and zincblende phases, whereas post-growth nitridation results in zincblende LaN. During deposition of the initial 2-3 nm, amorphous or disordered films with very small crystallites form, while the surface becomes smoother...
August 1, 2018: Journal of Applied Crystallography
Stephan Niebling, Alexander Björling, Sebastian Westenhoff
[This corrects the article DOI: 10.1107/S1600576714009959.].
June 1, 2018: Journal of Applied Crystallography
Sven C Vogel, Chris M Biwer, David H Rogers, James P Ahrens, Robert E Hackenberg, Drew Onken, Jianzhong Zhang
A tool named Cinema:Debye-Scherrer to visualize the results of a series of Rietveld analyses is presented. The multi-axis visualization of the high-dimensional data sets resulting from powder diffraction analyses allows identification of analysis problems, prediction of suitable starting values, identification of gaps in the experimental parameter space and acceleration of scientific insight from the experimental data. The tool is demonstrated with analysis results from 59 U-Nb alloy samples with different compositions, annealing times and annealing temperatures as well as with a high-temperature study of the crystal structure of CsPbBr3 ...
June 1, 2018: Journal of Applied Crystallography
P Scardi, M Ermrich, A Fitch, E-Wen Huang, R Jardin, R Kuzel, A Leineweber, A Mendoza Cuevas, S T Misture, L Rebuffi, Christian Schimpf
Separation of size and strain effects on diffraction line profiles has been studied in a round robin involving laboratory instruments and synchrotron radiation beamlines operating with different radiation, optics, detectors and experimental configurations. The studied sample, an extensively ball milled iron alloy powder, provides an ideal test case, as domain size broadening and strain broadening are of comparable size. The high energy available at some synchrotron radiation beamlines provides the best conditions for an accurate analysis of the line profiles, as the size-strain separation clearly benefits from a large number of Bragg peaks in the pattern; high counts, reliable intensity values in low-absorption conditions, smooth background and data collection at different temperatures also support the possibility to include diffuse scattering in the analysis, for the most reliable assessment of the line broadening effect...
June 1, 2018: Journal of Applied Crystallography
Pingguang Xu, Stefanus Harjo, Mayumi Ojima, Hiroshi Suzuki, Takayoshi Ito, Wu Gong, Sven C Vogel, Junya Inoue, Yo Tomota, Kazuya Aizawa, Koichi Akita
Neutron diffraction texture measurements provide bulk averaged textures with excellent grain orientation statistics, even for large-grained materials, owing to the probed volume being of the order of 1 cm3 . Furthermore, crystallographic parameters and other valuable microstructure information such as phase fraction, coherent crystallite size, root-mean-square microstrain, macroscopic or intergranular strain and stress, etc. can be derived from neutron diffractograms. A procedure for combined high stereographic resolution texture and residual stress evaluation was established on the pulsed-neutron-source-based engineering materials diffractometer TAKUMI at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Center, through division of the neutron detector panel regions...
June 1, 2018: Journal of Applied Crystallography
Marianna Marciszko, Andrzej Baczmański, Manuela Klaus, Christoph Genzel, Adrian Oponowicz, Sebastian Wroński, Mirosław Wróbel, Chedly Braham, Habib Sidhom, Roman Wawszczak
The main focus of the presented work was the investigation of structure and residual stress gradients in the near-surface region of materials studied by X-ray diffraction. The multireflection method was used to measure depth-dependent stress variation in near-surface layers of a Ti sample (grade 2) subjected to different mechanical treatments. First, the multireflection grazing incidence diffraction method was applied on a classical diffractometer with Cu  K α radiation. The applicability of the method was then extended by using a white synchrotron beam during an energy dispersive (ED) diffraction experiment...
June 1, 2018: Journal of Applied Crystallography
Weiwei Wang, A Dominic Fortes, David P Dobson, Christopher M Howard, John Bowles, Neil J Hughes, Ian G Wood
An apparatus is described for the compression of samples to ∼2 GPa at temperatures from 80 to 300 K, rapid chilling to 80 K whilst under load and subsequent recovery into liquid nitro-gen after the load is released. In this way, a variety of quenchable high-pressure phases of many materials may be preserved for examination outside the high-pressure sample environment, with the principal benefit being the ability to obtain high-resolution powder diffraction data for phase identification and structure solution...
June 1, 2018: Journal of Applied Crystallography
Ian G Wood, A Dominic Fortes, David P Dobson, Weiwei Wang, Lucjan Pajdzik, John Cosier
A low-temperature stage for X-ray powder diffraction in Bragg-Brentano reflection geometry is described. The temperature range covered is 40-315 K, with a temperature stability at the sample within ±0.1 K of the set point. The stage operates by means of a Gifford-McMahon (GM) closed-cycle He refrigerator; it requires no refrigerants and so can run for an extended period (in practice at least 5 d) without intervention by the user. The sample is cooled both by thermal conduction through the metal sample holder and by the presence of He exchange gas, at ambient pressure, within the sample chamber; the consumption of He gas is extremely low, being only 0...
June 1, 2018: Journal of Applied Crystallography
Stefan Mattauch, Alexandros Koutsioubas, Ulrich Rücker, Denis Korolkov, Vicenzo Fracassi, Jos Daemen, Ralf Schmitz, Klaus Bussmann, Frank Suxdorf, Michael Wagener, Peter Kämmerling, Harald Kleines, Lydia Fleischhauer-Fuß, Manfred Bednareck, Vladimir Ossoviy, Andreas Nebel, Peter Stronciwilk, Simon Staringer, Marko Gödel, Alfred Richter, Harald Kusche, Thomas Kohnke, Alexander Ioffe, Earl Babcock, Zahir Salhi, Thomas Bruckel
MARIA (magnetism reflectometer with high incident angle) is a world class vertical sample reflectometer dedicated to the investigation of thin films in the fields of magnetism, soft matter and biology. The elliptical vertically focusing guide allows one to measure small samples with a typical size of 1 × 1 cm very efficiently. The double-bounce polarizer and the in situ pumped 3 He SEOP (spin-exchange optical pumping) neutron spin filter cell for analysing the polarization of the reflected neutron beam can be moved into the beam in seconds...
June 1, 2018: Journal of Applied Crystallography
Michael Heere, Martin J Mühlbauer, Alexander Schökel, Michael Knapp, Helmut Ehrenberg, Anatoliy Senyshyn
The need for rapid data collection and studies of small sample volumes in the range of cubic millimetres are the main driving forces for the concept of a new high-throughput monochromatic diffraction instrument at the Heinz Maier-Leibnitz Zentrum (MLZ), Germany. A large region of reciprocal space will be accessed by a detector with sufficient dynamic range and microsecond time resolution, while allowing for a variety of complementary sample environments. The medium-resolution neutron powder diffraction option for 'energy research with neutrons' (ErwiN) at the high-flux FRM II neutron source at the MLZ is foreseen to meet future demand...
June 1, 2018: Journal of Applied Crystallography
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