Rapid and accurate methods are becoming available to calculate all of the relevant physical effects that contribute to an energy-dispersive X-ray fluorescence (EDXRF) spectrum, rather than just the characteristic line intensities given by the traditional fundamental parameters method. To evaluate the utility of such methods, we have calculated the full spectra of several compounds covering a wide range of compositions. The calculated spectra are compared directly with measured spectra. They include scattering of the X-ray tube lines and continuum, the Compton profile, and the detector response. Our results indicate that it is now possible to compute the full spectrum from an EDXRF system with very good accuracy.

X-ray powder diffraction data for a rhombohedral AlPt phase formed by self-propagating, high-temperature reactions of Al∕Pt bi-layer films are reported. Multilayer Al∕Pt thin film samples, reacted in air or vacuum, transformed into rhombohedral AlPt with space group R-3(148). Indexing and lattice parameter refinement of AlPt powders (generated from thin-film samples) yielded trigonal/hexagonal unit-cell lattice parameters of a=15.623(6) Å and c=5.305(2) Å, Z=39, and V=1121.5 Å3.

Ni20[(C6H8O4)20(H2O)8]∙33H2O, a new nickel(II) 3-methylglutarate, was prepared hydrothermally (180 °C, 48 h, autogenous pressure) from a 1:1.5:2:180 mixture of nickel (II) sulphate hexahydrate, 3-methylglutaric acid, sodium hydroxide, and water. It crystallizes in the cubic system (space group P4332, Z=1) with a=16.8488(5) Å and V=4783.1(4) Å3. Its structure was solved from conventional X-ray powder diffraction data. It presents a three-dimensional network of edge-sharing nickel octahedra, lined by deprotonated organic anions. This remarkable oxide network with corrugated 20-membered rings is constructed from homochiral helices. The rings intersect each other to generate large crossing channels full of water along [111].

Structures of two K2SnX(PO4)3(X=Fe,Yb) phosphates, obtained by conventional solid state reaction techniques at 950 °C, were determined at room temperature by X-ray powder diffraction using Rietveld analysis. The two materials exhibit the langbeinite-type structure (P213 space group, Z=4). Cubic unit cell parameter values are: a=9.9217(4) Å and a=10.1583(4) Å for K2SnFe(PO4)3 and K2SnYb(PO4)3, respectively. Structural refinements show that the two crystallographically independent octahedral sites (of symmetry 3) have a mixed Sn∕X (X=Fe,Yb) population although ordering is stronger in the Yb phase than in the Fe phase.

A series of complex perovskite solid solutions of Ba[(Mg1−xCdx)0.33Nb0.67]O3 have been synthesized by the columbite method. Detailed Rietveld refinement of their X-ray diffraction data show that Ba[(Mg1−xCdx)0.33Nb0.67]O3 has an order trigonal structure. The ordering degree as determined by the B-site occupancies increases with the partial substitution of Cd for Mg. However, a decrease in the ordering degree in the Ba(Cd0.33Nb0.67)O3 sample is observed, which can be attributed to a relatively lower synthesis temperature. All the impurity phases are successfully identified by X-ray quantitative phase analysis. Dielectrics properties at low frequencies for all the Ba[(Mg1−xCdx)0.33Nb0.67]O3 compounds have been measured successfully.

The structure of a chemical-vapor-deposited (CVD) diamond thin film on a Mo substrate was studied using quasi-parallel X-ray and glancing incidence techniques. Conventional X-ray diffraction analysis revealed that the sample consists of a diamond thin film, a Mo2C transition layer, and Mo substrate. The Mo2C transition layer was formed by a chemical reaction between the diamond film and the Mo substrate during the CVD process. A method for layer-thickness determination of the thin film and the transition layer was developed. This method was based on a relationship between X-ray diffraction intensities from the transition layer or its substrate and a function of grazing incidence angles. Results of glancing incidence X-ray diffraction analysis showed that thicknesses of the diamond thin film and the Mo2C transition layer were determined successfully with high precision.

Silver K edge extended X-ray absorption fine structure (EXAFS) spectroscopy of films containing silver behenate (AgBeh) in the unprocessed, fully processed, and step-processed states has been performed. The results of the EXAFS analysis indicate that the intensity for the real-space peak for the Ag-O distance (∼2.3 Å) decreases while the real-space peak for the Ag-Ag distance (∼2.9 Å) grows with increasing thermal processing of the film. The changes observed in the real-space EXAFS signal indicate the growth of metallic silver at the expense of AgBeh. The X-ray absorption near-edge spectroscopy (XANES) portion of the signal shows that the absorption edge position varies stepwise, with unprocessed films and pure AgBeh having an edge location at 25 506 eV, films processed from steps 1 through 10 have an absorption edge at 25 508 eV, and the fully processed film has an edge location at 25 512 eV.

The nanostructural features of the gas-phase displacement reaction 2Mg(g)+SiO2→2MgO(s)+{Si}, where SiO2 is in the form of diatom shells were studied via X-ray diffraction and Fourier methods. Diatomaceous powder heated to 700 °C in a sealed graphite cell in the presence of Mg vapor formed MgO via a displacement reaction. Warren-Averbach analysis performed on samples reacted for different times showed an initial sharp MgO grain size distribution which broadened with time. New MgO crystallization was shown to occur until about 60 min, whereafter only MgO grain growth occurred. Median MgO crystallite size increased from 7.5 to 24.9 nm during this period, whereas microstrain decreased dramatically past 60 min annealing time.

The definitions for important Rietveld error indices are defined and discussed. It is shown that while smaller error index values indicate a better fit of a model to the data, wrong models with poor quality data may exhibit smaller values error index values than some superb models with very high quality data.

Recent developments at synchrotron X-ray beamlines now allow collection of data suitable for structure determination and Rietveld structure refinement at high pressures and temperatures on challenging materials. These include materials, such as dolomite(CaMg(CO3)2) that tends to calcine at high temperatures, and Fe-containing materials, such as the spinel MgFe2O4, which tend to undergo changes in oxidation state. Careful consideration of encapsulation along with the use of radial collimation produced powder diffraction patterns virtually free of parasitic scattering from the cell in the case of large volume high-pressure experiments. These features have been used to study a number of phase transitions, especially those where superior signal-to-noise discrimination is required to distinguish weak ordering reflections. The structures adopted by dolomite, and CaSO4, anhydrite, were determined from 298 to 1466 K at high pressures. Using laser-heated diamond-anvil cells to achieve simultaneous high pressure and temperature conditions, we have observed CaSO4 undergo phase transitions to the monazite type and at highest pressure and temperature to crystallize in the barite-type structure. On cooling, the barite structure distorts, from an orthorhombic to a monoclinic lattice, to produce the AgMnO4-type structure.

Calibration of powder diffraction experiments using area detectors is essential to extract high quality one-dimensional powder diffraction pattern. Precise calibration necessitates a sensible characterization of the Debye-Scherrer rings formed on the detector plane. An algorithm, designed and developed to automate this process, is described in this paper. All the parameters required for an experimental calibration are extracted using robust pattern recognition techniques. Several image preprocessing methods are employed, reducing the computational cost but retaining high signal quality. A modified version of a one-dimensional Hough transformation is used to determine the final parameters of the ellipses. After extraction, the parameters are optimized using nonlinear least squares fit. The presented algorithm is insensitive to image artefacts and was successfully applied to a large number of calibration images. The performance of the algorithm is demonstrated by the comparison of results obtained from the presented automatic calibration method and an existing manual method.

This work introduces a new simple approach to determine experimental X-ray elastic constants (XECs) of thin films by coupling the sin2ψ method and the substrate curvature technique. The approach is demonstrated on polycrystalline Cu thin films with the thickness 200, 800, and 2400 nm deposited on Si(100) substrates. Applying synchrotron radiation, the elastic strains in the films are determined using sin2ψ method while the macroscopic stresses are assessed by measuring the substrate curvature. The stresses are calculated using the Stoney formula from the radius of substrate curvature determined by the rocking curve measurement of substrate 400 reflection at different sample positions. Results show that the magnitude of the macroscopic stress in the films is proportional to the magnitude of the slope in the sin2ψ plots. On the basis of this observation, XECs of the films were calculated showing no dependence on the film thickness. The characterization of the samples was performed at the synchrotron source Hasylab.

Structural properties of Cd1−xCuxCr2O4(CCCO) have been investigated by means of X-ray powder diffraction and Rietveld analysis. A structural phase transformation from Fd3m to I42d at x=0.64 has been detected. The lattice constant a of the cubic unit cell decreases rapidly with increasing Cu content up to x=0.62. At x=0.64, the cubic unit cell is compressed into a tetragonal cell and CrO6 octahedrons are distorted. With continuing Cu content increases above 0.64, the distortion of the unit cell is released slightly according to the changes in c/a. Magnetic properties of Cd1−xCuxCr2O4(x=0.1,0.3,0.5,0.7) have also been measured and are discussed.