Synchrotron X-ray diffraction

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High-Pressure Study of Molecular Solids and 1D Nanostructures by Vibrational Spectroscopy and Synchrotron X-ray Diffraction

High-Pressure Study of Molecular Solids and 1D Nanostructures by Vibrational Spectroscopy and Synchrotron X-ray Diffraction

significantly different band profile. This is consistent with the finding that the BNNT wurtzite structure may be contributed by both the inter- and the intra-tubular linking, whereas the bulk h-BN structure arose only from interlayer linking. The abundance ratio of w-BN to h-BN (Fig. 5.3) along the BNNT transitions provided a possible estimate of the threshold pressure above which intra-tubular linking becomes significant. That is, the second region of 11 – 20 GPa likely corresponds to inter-tubular linking, whereas in the third region above 20 GPa, intra-tubular linking might play a major role in the conversion to a wurtzite structure. These observations strongly support the different mechanisms of sp 3 bonding formation between the two BN materials. Additional theoretical investigations on high-pressure structures and MWBNNT bonding patterns would be helpful for understanding the detailed transformation process. Further in-situ structural investigations, such as synchrotron X-ray diffraction and inelastic X-ray scattering, 22
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Synchrotron X-Ray Diffraction Studies of Domain Reorientation in Lead Zirconate Titanate.

Synchrotron X-Ray Diffraction Studies of Domain Reorientation in Lead Zirconate Titanate.

Diffraction patterns were measured in situ during simultaneous application of electric fields and mechanical load using high-energy X-rays at beamline 11-ID-C of the Advanced Photon Source at Argonne National Laboratory. Each individual sample was mounted in the screw-driven testing fixture described above. Electrode connections were attached to the high voltage source via alligator clips. Diffractio n data were measured in transmission mode using a wavelength of 0.11798 Å, and 0.5 mm × 0.5 mm slit size. A cerium dioxide (NIST 674b) standard was used to calibrate sample-to-detector distance, beam center, and detector orthogonality for data reduction fr om two- dimensional (2D) XRD patterns using the Fit2D program[96]. Samples were cycled 3 times using a unipolar triangular waveform and an electric field amplitude of 3 kV/mm (cf. top diagram in Figure 79). A script was written to effectively synchronize the diffracted X-ray beam with applied voltage and macroscopic measurements. A schematic of the experimental setup used to simultaneously measure the macroscopic properties (polarization and strain) and structural response to applied pre-stress and electric field is shown in Figure 74. A full wired diagram is available in the supporting information in Appendix E.
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Elastic and Plastic Deformation Behavior Studied by In Situ Synchrotron X ray Diffraction in Nanocrystalline Nickel

Elastic and Plastic Deformation Behavior Studied by In Situ Synchrotron X ray Diffraction in Nanocrystalline Nickel

Normal direction (ND) - rolling direction (RD) cross-sec- tions of the ARB-Ni samples were mechanically polished with SiC paper followed by chemical-mechanical polishing using colloidal silica. Grain sizes were determined based on the electron beam backscattering diffraction (EBSD) method employing orientation imaging microscopy (OIM; TSL) and field-emission scanning electron microscopy (FE-SEM; JEOL JSM6500F) at an accelerating voltage of 15 kV. The mean grain size in each specimen was taken as equal to the ND spacing of the high-angle boundaries. The mean grain sizes of electrodeposited NC-Ni samples were determined from microstructural observations of dark field images ac- quired with transmission electron microscopy (TEM; JEOL JEM-2010) at an accelerating voltage of 200 kV. The grain sizes of NC-Ni samples were assessed using image quality
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Time resolved synchrotron x ray diffraction studies of the crystallization of amorphous Co(80 x)FexB20

Time resolved synchrotron x ray diffraction studies of the crystallization of amorphous Co(80 x)FexB20

lattice parameters as a function of time annealed were determined. It should be noted that because Fe and Co are almost completely indistinguishable by x-rays a 50-50% occupation was assumed and site occupancies were kept constant. Typically in iron metalloid glasses, phase formation progresses with a primary phase formation of α -Fe 11-13 , while in CoFeB alloys Co and Fe atoms form continuous solid solutions in the α - Fe phase to form α-(Co,Fe) 14 .

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Crystal structure of bis­­[cis (1,4,8,11 tetra­aza­cyclo­tetra­deca­ne κ4N)bis­(thio­cyanato κN)chrom­ium(III)] dichromate monohydrate from synchrotron X ray diffraction data

Crystal structure of bis­­[cis (1,4,8,11 tetra­aza­cyclo­tetra­deca­ne κ4N)bis­(thio­cyanato κN)chrom­ium(III)] dichromate monohydrate from synchrotron X ray diffraction data

The resulting solution was evaporated slowly at room temperature until formation of crystals. The obtained block- like orange crystals of the dichromate salt were washed with small amounts of 2-propanol and dried in air before collecting the synchrotron data. Elemental analysis calculated for [Cr(NCS) 2 (C 10 H 24 N 4 )] 2 (Cr 2 O 7 )H 2 O: C, 29.69; H, 5.19; N,

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Anisotropic magnetoelastic coupling in single crystalline CeFeAsO as seen via high resolution x ray diffraction

Anisotropic magnetoelastic coupling in single crystalline CeFeAsO as seen via high resolution x ray diffraction

To summarize, we demonstrate that with high-resolution synchrotron x-ray diffraction, the twin domains observed in single-crystal CeFeAsO can be distinct, allowing the practical study of an individual untwinned crystal. Most importantly, we find that the charge correlations show a significant anisotropy along and perpendicular to the stripe-type 2D AFM wave vector. This is consistent with the anisotropic 2D spin correlations, indicative of an anisotropic 2D magnetoelastic coupling, and implies that the AFM ordering is the driving force for the structural T-to-O transition in this system. In addition, we show that the misfit-angle difference of the O twin domains (a macroscopic variable) follows well the O strain (or shearing) order parameter, indicating that it can be used to monitor the order parameter of the O-T structural transition. Furthermore, based on the observed charge-correlation lengths of the O twin domains and the T domain below and above T S , respectively, we argue that at high temperatures the system is virtually a T phase that exhibits strong O/T structural fluctuations. This fluctuating phase is probably induced by the strong spin fluctuations, most likely by the spin-nematic phase.
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Online Full Text

Online Full Text

Abstract— Magnesium alloys are becoming increasingly popular in industrial applications due to their low density and high specific strength. The improvements sought in the formability at ambient temperature and fracture resistance of magnesium alloy AZ31B can be attained through the use of Severe Plastic Deformation (SPD). In order to investigate the deformation response of this material, in situ three-point bending test was performed on a sample extracted from a plate subjected to SPD by constrained groove pressing (CGP). High-energy synchrotron X-ray diffraction was used to examine the lattice strains across the sample. It revealed that significant tension-compression asymmetry is observed for some grain groups. Twinning deformation mode is observed under compressive loading differs from other modes. Additionally, it has been shown that plastic deformation proceeds more readily within grains which experience loading parallel to the basal plane. This is in contrast to the grains whose c-axis is aligned with the loading direction. Stress-strain curves were obtained from XRD and they agree well with results from mechanical test.
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Combining microscopic and macroscopic probes to untangle the single ion anisotropy and exchange energies in an S=1 quantum antiferromagnet

Combining microscopic and macroscopic probes to untangle the single ion anisotropy and exchange energies in an S=1 quantum antiferromagnet

While there is no substitute for the detailed study of single crystals, the success of this work on pow- der samples demonstrates the complementary capabil- ities of the micro- and macroscopic probes involved. More specifically, the experimental sequence is as fol- lows: (i) micro-crystal synchrotron X-ray diffraction de- termines the crystal structure; (ii) using this structure, an analysis of the powder-elastic neutron diffraction es- tablishes the magnetic ground state and charts the evo- lution of the ordered moment as a function of temper- ature; (iii) from this ground-state magnetic structure, an analysis of the powder-inelastic neutron scattering determines the magnetic exchange and anisotropy pa-
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High Pressure Studies of Nanostructured TiO2 and Li4Ti5O12 Using Raman Spectroscopy and Synchrotron X-ray Radiation

High Pressure Studies of Nanostructured TiO2 and Li4Ti5O12 Using Raman Spectroscopy and Synchrotron X-ray Radiation

In situ high-pressure structural characterization was performed using a customized Raman spectroscopy and synchrotron X-ray diffraction with detailed instrumental information described in Chapter 1. Specifically, A 532 nm wavelength laser was used as the excitation source for Raman spectra. The Raman system was calibrated by neon lines with an uncertainty of ± 1 cm −1 . Raman data for each pressure point were collected in the spectral region of 100-800 cm -1 , corresponding to the lattice vibrations with accumulation time of 180 s. In situ angle-dispersive X-ray diffraction measurements were carried out at room temperature at the beamline Sector-20ID of Advanced Photon Source (APS) in Argonne National Laboratory (ANL). The incident wavelength is 0.4769 Å with a beam size of 5 μm (H) x 5 μm (V) focused at the center of the sample. The diffraction data were recorded with an exposure time of 60 s, and the 2D Debye-Scherrer diffraction patterns were integrated by using Fit2D program for further analysis. A Rietveld analysis was performed using the GSAS+EXPGUI program. More details about Fit2D and Rietveld refinement programs are provided in Appendix I.
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Single crystal growth, structure and magnetic properties of Pr2Hf2O7 pyrochlore

Single crystal growth, structure and magnetic properties of Pr2Hf2O7 pyrochlore

In addition to the powder synchrotron X-ray diffraction pattern measured on the starting polycrystalline material, a measurement was also performed on a sample obtained by grinding a tiny crystal fragment from the middle of a single crystal. The drawbacks of using a powdered crystal fragment were the small amount of the resulting powder and the difficulty in grinding the crystal sample into very fine particles. The aforementioned factors hindered the realization of a full Rietveld analysis, because of insufficient powder averaging and poorly modelled lineshapes. Instead, that data was analyzed by a Le Bail decomposition [51] that was good enough to provide a precise estimate of the lattice parameter. The agreement factors for the refinement of the powder diffraction data given in the manuscript are defined in Ref. [52].
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Online Full Text

Online Full Text

Mesoscopic theoretical frameworks and modeling techniques are being developed that bridge the gap between length-scale boundaries. It is important to note, however, that meaningful development of these refined scale frameworks or “bridging” models only becomes possible when corresponding material deformation characterisation methods become available, such as e.g. laser extensometry, digital image correlation (DIC) and synchrotron X-Ray diffraction. These are employed to probe the material deformation at the corresponding scales, and serve as excellent tools for the determination of crucially important model material parameters needed for the simulation. This paper presents an overview of the recent advances in multi-scale and experimentally validated modeling conducted within the Oxford HEX-lab group [1,2]. The scope of studies presented spans the range of high- performance alloys, from macroscopic nonlocal damage- plasticity models applied to ductile Al alloys to eigenstrain- based fatigue simulations in light Mg alloys to strain gradient dislocation-based modeling of intragranular deformation in commercially pure Ni.
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LiMn2O4: a spinel related low temperature modification

LiMn2O4: a spinel related low temperature modification

other authors but high precision single-crystal X-ray diffrac- tion experiments, in principle, can provide more accurate three-dimensional information about the electron density. Akimoto et al. (2000) have already revealed details of single- crystal studies of the HT phase, so here we report the LT structure determined via single-crystal synchrotron X-ray diffraction. The structure of the LT phase was ®rst determined in a powder neutron diffraction experiment (RodrõÂguez- Carvajal et al., 1998). In that analysis, the atomic displacement parameters (ADPs) were treated isotropically and constrained to identical values for each chemical element. In the current study, the greater experimental precision of the single-crystal experiment permitted re®nement of anisotropic ADPs for all atom sites, with more precise positional parameters (Fig. 1 and 2). Our study con®rms the Fddd symmetry adopted by RodrõÂguez-Carvajal et al., but the atomic positions differ somewhat from their results. The atomic positions directly affect the interatomic bond lengths and these, in turn, are strongly correlated with constituent atomic valences. Bond valence sums (BVS; Brown & Altermatt, 1985) determined for each Mn site are 3.06 for Mn1, 3.34 for Mn2, 3.12 for Mn3, 3.89 for Mn4, and 3.88 for Mn5, averaging to 3.50 over the unit cell. The average is, therefore, perfectly consistent with the LiMn 2 O 4 composition. The evidence suggests that the Mn4
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Emphysema early diagnosis using X-ray diffraction enhanced imaging at synchrotron light source

Emphysema early diagnosis using X-ray diffraction enhanced imaging at synchrotron light source

Methods: In this article, we used diffraction enhanced imaging (DEI) method to get the images of early stage emphysematous and healthy samples, then extract X-ray absorption, refraction, and ultra-small-angle X-ray scattering (USAXS) information from DEI images using multiple image radiography (MIR). We combined the absorption image with the USAXS image by a scatter plot. The critical threshold in the scatter plot was calibrated using the linear discriminant function in the pattern recognition. Results: USAXS image was sensitive to the change of tissue micro-structure, it could show the lesions which were invisible in the absorption image. Combined with the absorption-based image, the USAXS information enabled better discrimination between healthy and emphysematous lung tissue in a mouse model. The false-color images demonstrated that our method was capable of classifying healthy and emphysematous tissues.
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Molecular Fullerides

Molecular Fullerides

The research described in this dissertation was undertaken primarily at the Australian National University, under the supervision of Professor John White. Data collection described herein was in three instances performed elsewhere: X-ray synchrotron diffraction data was collected at the Australian National Beamline Facility in Tsukuba, Japan; neutron diffraction patterns were recorded at the Intense Pulsed Neutron Source at the Argonne National Laboratories in Illinois, USA; and inelastic neutron scattering measurements were made at the ISIS Pulsed Neutron Source of the Rutherford Appleton Laboratory, Chilton, UK.
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Crystal structure of penta­sodium hydrogen dicitrate from synchrotron X ray powder diffraction data and DFT comparison

Crystal structure of penta­sodium hydrogen dicitrate from synchrotron X ray powder diffraction data and DFT comparison

Use of the Advanced Photon Source at Argonne National Laboratory was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02–06CH11357. This work was partially supported by the International Centre for Diffraction Data. We thank Lynn Ribaud for his assistance in data collection.

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Laumann, Andreas
  

(2011):


	Novel routes to Li4Ti5O12 spinel: Characterization and phase relations.


Dissertation, LMU München: Fakultät für Geowissenschaften

Laumann, Andreas (2011): Novel routes to Li4Ti5O12 spinel: Characterization and phase relations. Dissertation, LMU München: Fakultät für Geowissenschaften

Synchrotron diffraction enables enhanced crystallographic investigations using X-ray beams of high brilliance, which can be employed to measure particles of small size and in small amounts, but with short exposure times, which makes it feasible to study the kinetics of rapid reactions (Cerenius et al., 2000). The experiments presented in Chapter 3 were performed at the crystallography beam-line I711 at the synchrotron MAX-lab II in Lund, Sweden. A photo of the setup is shown in Figure C.1 in the supplementary material 2 of Appendix C. In this setup, the synchrotron beam has to pass through a sapphire capillary, the hydrothermal solution and still has enough energy to extract the crystallographic information of the crystalline powder. This is only enabled by a very high flux, which at beam-line I711 is approximately 1011 photons s −1 at a wavelength of 0.997 ˚ A. With a time-resolution of 10.5 s per exposure, single exposures could be recorded. Firstly, thorough masking (e.g. of the beam-stop and noise in form of spikes (See Figure C.2 in the supplementary material 2 of Appendix C) of the obtained two-dimensional frames was done with the program FIT 2D (Hammersley et al., 1996) before the data was converted to ASCI files, which can be read with a wide range of analysis programs. The structural Rietveld refinements were performed with the program FullProf.
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Rietveld refinement of Ba5(AsO4)3Cl from high resolution synchrotron data

Rietveld refinement of Ba5(AsO4)3Cl from high resolution synchrotron data

The powdered sample was loaded into a 0.7 mm diameter borosilicate capillary, prior to high-resolution synchrotron X-ray powder diffraction data collection using station 9.1 of the Daresbury Synchrotron Radiation Source. The beam on the sample was 13 mm wide and 1.2 mm high. 9 powder datasets were collected, all were with a step with of 0.01°/2θ and a counting time of 2 s per point. Three of these datasets were collected between 5–70°/2θ, two between 30–70°/2θ, two between 40–70°/2θ, one between 31.73–70°/2θ and one between 2–13.2°/2θ. All of these data were summed and normalized to account for decay of the synchrotron beam with time. The main Bragg reflections of the powder diffraction pattern could be indexed in space group P6 3 /m with similar lattice parameters to those of the published powder diffraction data (Kreidler & Hummel, 1970).
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Trisodium citrate, Na3(C6H5O7)

Trisodium citrate, Na3(C6H5O7)

solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory (DFT). There are two independent five-coordinate Na + and one six-coordinate Na + cations in the asymmetric unit. The [NaO 5 ] and [NaO 6 ] polyhedra share edges and corners to form a three-

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Quantifying Isotibolone in Raw Materials of Tibolone

Quantifying Isotibolone in Raw Materials of Tibolone

Isotibolone can be adequately identified and quantified using the Rietveld method and synchrotron X-ray powder diffraction data. In the case of pharmaceutical com- pounds, high resolution is very important when per- forming an accurate quantitative analysis, since there is a high degree of peak overlap due to the presence of low symmetry space groups. In this work the presence of the unwanted tibolone isomer in raw materials was only observed as low-intensity peaks and shoulder peaks in the main tibolone phase. Laboratory resolution with a high-divergence Soller slit can be used only for identi- fication of isotibolone, if the main phase is triclinic.
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Rietveld refinement of Ba5(AsO4)3Cl from high resolution synchrotron data

Rietveld refinement of Ba5(AsO4)3Cl from high resolution synchrotron data

The powdered sample was loaded into a 0.7 mm diameter borosilicate capillary, prior to high-resolution synchrotron X- ray powder diffraction data collection using station 9.1 of the Daresbury Synchrotron Radiation Source. The beam on the sample was 13 mm wide and 1.2 mm high. 9 powder datasets were collected, all were with a step with of 0.01°/2 θ and a counting time of 2 s per point. Three of these datasets were collected between 5–70°/2 θ , two between 30–70°/2 θ , two between 40–70°/2 θ , one between 31.73–70°/2 θ and one between 2–13.2°/2 θ . All of these data were summed and
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