The crystal structures of ASnFe(PO4)3 (A=Na2, Ca, Cd) phases, obtained by conventional solid state reaction techniques at (950–1000 °C), were determined at room temperature from X-ray powder diffraction (XRD) using Rietveld analysis. The three materials exhibit the Nasicon-type structure (R3c space group, Z=6) with a random distribution of Sn(Fe) within the framework. Hexagonal cell parameters when A=Na2, Ca and Cd are: a=8.628(1) Å, c=22.151(2) Å; a=8.569(1) Å, c=22.037(2) Å and a=8.587(1) Å, c=21.653(2) Å, respectively. Structural refinements show a partial occupancy of M1 (Na(1)) and M2 (Na(2)) sites in Na2SnFe(PO4)3 leading to the cationic distribution [Na1.22□1.78]M2[Na0.78□0.22]M1SnFe(PO4)3. Ca2+ ions are distributed only in the M1 site of [□3]M2[Ca]M1SnFe(PO4)3. From XRD data, it is difficult to unambiguously distinguish between Cd2+ and Sn4+ ions in CdSnFe(PO4)3. Nevertheless the overall set of cation–anion distances within the Nasicon framework clearly shows that the cationic distribution can be illustrated by the [□3]M2[Cd]M1SnFe(PO4)3 crystallographic formula. Distortion within the [Sn(Fe)(PO4)3] frameworks, in ASnFe(PO4)3 (A=Na2,Ca,Cd) phases, is shown to be related to the M1 site size. © 2004 International Centre for Diffraction Data.

Crystal structures of (NH4)2KWO3F3 at 298 K and 113 K were solved from X-ray powder diffraction data and refined by the Rietveld technique. The compound is isostructural with elpasolite K2NaAlF6 at room temperature with space group Fm-3m, a=8.95850(5) Å, V=718.961(7) Å3, Z=4, Dx=3.363 g/cm3, and MW=364.02. The structure was refined over 18 parameters to Rwp=12.6%, Rp=10.9%, Rexp=5.03%, and RB=3.27% from 40 independent reflections. (NH4)2KWO3F3 was transformed upon cooling to a ferroelastic monoclinic phase with space group P21/n, a′=6.3072(3) Å, b′=6.3028(3) Å, c′=8.9882(3) Å, β′=90.242(2)°, V=357.30(3) Å3, Z=2, and Dx=3.383 g/cm3. The low-temperature structure at 113 K was refined over 28 parameters to Rwp=20.9%, Rp=21.3%, Rexp=12.5%, and RB=6.93% from 453 independent reflections.

X-ray diffraction (XRD) has been routinely employed in the Earth sciences to characterize the crystallography of rocks and minerals. Routine characterization of samples too small for analysis by classic automated powder diffraction methods becomes challenging without access to single crystal or micro-diffraction equipment. Here, we show that a traditional Gandolfi camera lined with an image-plate (IP) as the detection medium can return a fully quantitative diffraction pattern from a sub-milligram single grain specimen in a simple and straightforward manner. Data pertaining to peak positions (d-spacings) were assessed using SRM640c Si powder, while intensity data were compared to the certified values for intensity standard SRM676a alumina powder. The refined unit-cell dimension of Si powder differed from the certified value of 5.4312 Å by no more than 0.0003 Å with a standard deviation (σ) of 0.0002 Å among the three experiments. For intensity, the σ and disparity from the certified values of three diffraction experiments on SRM676a were both <2%. The results of a comparative study of the crystallographic parameters determined for a naturally occurring garnet and clinopyroxene given through the refinement of their crystal structure by single-crystal XRD method are presented. These show through Rietveld refinement of X-ray data obtained by the Gandolfi–IP method outlined here that both accurate and precise XRD data can be produced in a timely and cost-effective manner using only an IP, Gandolfi camera, and software freely available on the internet.

A Rietveld refinement of X-ray powder diffraction data for orthorhombic BaNd2Mn2O7 is reported. The refined lattice parameters were a=0.5517(5), b=0.5482(3), and c=2.0585(7) nm with space group Fmmm (No. 69).

Total reflection X-ray fluorescence analysis (TXRF) is a method for qualitative and quantitative analysis of trace elements. In general TXRF is known to allow for linear calibration typically using an internal standard for quantification. For small sample amounts (low ng region) the thin film approximation is valid neglecting absorption effects of the exciting and the detected radiation. However, for higher total amounts of samples deviations from the linear relation between fluorescence intensity and sample amount have been observed. The topic of the presented work is an investigation of the parameters influencing the absorption phenomenon. Samples with different total amounts of arsenic have been prepared to determine the upper limit of sample mass where the linear relation between fluorescence intensity and sample amount is no longer guaranteed. It was found that the relation between fluorescence intensity and sample amount is linear up to ∼100 ng arsenic. A simulation model was developed to calculate the influence of the absorption effects. Even though the results of the simulations are not satisfying yet it could be shown that one of the key parameters for the absorption effect is the density of the investigated element in the dried residues.

The nucleation of dislocations at indents in silicon following rapid thermal annealing (RTA) has been examined by X-ray diffraction imaging (topography). For indentation loads below 200 mN, no slip bands were generated from the indent sites following RTA at 1000 °C under spike conditions. Upon plateau annealing at 1000 °C, slip dislocations were propagated from some indents but not all. Slip was also observed from edge defects not associated with indentation. For 500-mN indentation load, large scale dislocation sources were generated from the indent sites propagating on two of the four {111} slip planes. These dislocations multiplied into macroscopic-scale slip bands. A significant change in morphology was observed in the 60° dislocation segments after the screw segment reached the rear surface of the wafer. Dislocations changed line direction and in some cases appeared to leave the Peierls trough during glide.

Research is being conducted on low energy x-ray and electron physics and application in the 100-1000 eV region. Work on the optimization of fluorescence analysis for light elements, including the development of efficient dispersive systems as the multilayer analysers of the Langmuir-Blodgett type, has been continued. Along with the ultrasoft x-ray program has been one on photoelectron and Auger electron spectroscopy. An evaluation of the application of low energy electron spectroscopy for surface characterization is being made.

The physical meaning of non-linearities in “d” vs. sin2ψ lines, encountered in X-ray measurements of surface residual stresses in polycrystalline materials is investigated. It is shown that when oscillations are present in any one reflection, switching to another reflection to obtain a straight line in “d“ vs. sin2.ψ is feasible only under very special conditions. We also discuss the effect of “quasi-homogeneous” strain distributions and investigate the effects of ψ-range on the accuracy of X-ray residual stress measurements when ψ-splitting” is present. A new geometric error is also discussed that can not be detected by the “annealed powder” method often used for alignment.

The apparatus for X-ray diffraction imaging (XRDI) of 450-mm wafers, is now placed at the ANKA synchrotron radiation source in Karlsruhe, is described in the context of the drive to inspect wafers for plastic deformation or mechanical damage. It is shown that full wafer maps at high resolution can be expected to take a few hours to record. However, we show from experiments on 200-, 300-, and 450-mm wafers that a perimeter-scan on a 450-mm wafer, to pick up edge damage and edge-originated slip sources, can be achieved in just over 10 min. Experiments at the Diamond Light Source, on wafers still in their cassettes, suggest that clean-room conditions may not be necessary for such characterization. We conclude that scaling up of the 300-mm format Jordan Valley tools, together with the existing facility at ANKA, provides satisfactory capability for future XRDI analysis of 450-mm wafers.

Ga2−xFexO3 (GFO) bulks with x from 0.7 to 1.3 have been fabricated using the classic solid-state route. The structural, optical, and magnetic properties have been investigated systematically. X-ray diffraction spectra and FULLPROF profile fitting indicate that GFO bulks belong to the orthorhombic structure with the space group Pc21n. Phase separation appears at the Fe content of x = 1.3. The optical bandgap decreases almost linearly with the increase of iron content, which means that the bandgap of GFO bulks can be controlled by adjusting the Fe content in the samples. The magnetic property measurements suggest that GFO is ferromagnetic, and the magnetic properties are enhanced compared with other reported works, exhibiting the application in ferromagnetic semiconductors devices.

Polycrystalline AgIn3Te5 synthesized by melt-quench technique has been analyzed using proton induced X-ray emission (PIXE), X-ray diffraction (XRD), and selected area electron diffraction. PIXE analysis yielded the content of Ag, In, and Te, respectively, to be 9.76%, 31.18%, and 59.05% by weight. Structure refinement was carried out considering those space groups from I- and P-type tetragonal systems which possess 4 symmetry and preserve the anion sublattice arrangement of the chalcopyrite structure (space group: I42d) as well. The results showed that AgIn3Te5 synthesized by melt-quench method crystallizes with P-type tetragonal structure (space group: P42c; unit-cell parameters a = 6.2443(8) and c = 12.5058(4) Å), the presence of which was corroborated by selected area electron diffraction studies.

The compounds BaR2O4, (R = Pr, Tb), where R are two of the less frequent trivalent lanthanides, have been prepared under reducing atmosphere from mixtures of BaO2, the R metals, and the oxides Pr2O3 and Tb4O7, respectively. The crystal structure of BaR2O4 have been refined from X-ray powder diffraction data by the Rietveld method of profile analysis using 31 parameters in each case. Both oxides are orthorhombic, isotypic with SrY2O4, of the perovskite-related CaFe2O4 structure type, S.G. Pnma (No. 62), Z = 4, a = 10.6113(8), b = 3.6303(3), c = 12.485(1) Å, and V = 480.93(5) Å3 for R = Pr; and a = 10.4282(8), b = 3.4893(3), c = 12.1809(6) Å, and V = 443.22(3) Å3 for R = Tb. The R–O distances vary between 2.15(6) to 3.40(6) Å for R = Pr, and between 2.15(3) to 2.91(5) Å for R = Tb.

We have used synchrotron X-ray diffraction experiments to measure the strain field introduced by a hydride blister grown on a section of a pressure tube from a CANDU nuclear reactor. After charging the tube section with a homogeneous hydrogen concentration of 300 wt ppm, the blister was produced by creating a small cold spot on its surface (∼200 °C), while the bulk was kept at a temperature of 338 °C over a period of 1008 h. The blister studied here is ellipsoidal in shape, with its long axis along the tube axial direction. The experiments were performed on the wiggler beam line ID15 at the European Synchrotron Radiation Facility (ESRF) using a polychromatic beam of high-energy X-rays (60 to 300 keV). Unlike conventional X-ray diffraction, in this mode the scattering angle is fixed and the diffracted beam is discriminated on the basis of the photon energy. The results show that the blister is composed by two crystallographic phases (δ-ZrH and α-Zr), with volume fractions varying with position. The maximum stresses appear at the blister-matrix interfaces. Near the tube outer surface, we found large compressive stresses of (−450±90) MPa along the blister long axis, and tensile stresses (+320±90) MPa along the tube hoop direction. The main uncertainty in these stresses results from the uncertainty in the elastic constants of the hydride phase. Large strains and broad peaks were observed for this phase, which were explained by a rather low Young’s modulus (35 GPa) for the hydride. The results are compared with finite element simulations found in the literature.

X-ray powder diffraction data for the spinels CoAl2O4 and CoGa2O4 were measured with synchrotron radiation using λ = 1.2033 Å, determined with Si as a standard (a = 5.4305 Å). The two blue compounds prepared hydrothermally are cubic with space group Fd3m. Profile refinements gave the results: CoAl2O4 had a = 8.0968(1) Å and composition (Co0.71Al0.29]Al1.71Co0.29]O4 and CoGa2O4 had a = 8.3229(1) Å and composition Ga[CoGa]O4. The degree of inversion is thus 0.29 for CoAl2O4 and one for CoGa2O4.

Internal stresses and textures of electroplated copper films (t=2, 8, 15, 30, 45, and 60) electrodeposited on Al substrates were studied using X-ray diffraction techniques. Results show that the stresses in the films are tensile. The 8 to 60 μm thick films have (220) fiber texture, in good agreement with strain energy minimization calculation. Results also show that a further rotational alignment of the fiber-textured grains was developed, and small amounts of the fiber-textured grains have their (2, −2, 0) planes aligned parallel to the flow direction of the electrodeposited currents. The degree of the rotation alignment increases with film thickness. Values of stress and the degree of texture of copper films were found to be adjustable using an ultrasound technique. Internal stress and the degree of the (220) texture decrease significantly by applying an ultrasound treatment during the electrodeposition process.

A comparison between the results of ab initio structure determination from X-ray powder diffraction data of a new cadmium hydroxide nitrate, Cd5(OH)8 (NO3)2·2H2O (SG C2/m), and those obtained from single crystal data is presented. The powder diffraction pattern has been analysed by an indexing method and fitting techniques. A total of 119 unambiguously indexed reflections has been extracted and used in subsequent treatment. The power of powder techniques to index the pattern and to find the structure model by normal Patterson and Fourier methods is clearly shown. The refinement of approximate coordinates has been carried out by the Rietveld method (444 reflections). The comparison of results with those obtained from single crystal data (2218 reflections) shows that the precision of positional parameter values is lower by a factor of 10, on average, in the powder study. These results are discussed in terms of crystallographic parameters (number of reflections used, number of parameters to refine, contrast between atoms) and, also, in terms of sample dependent properties (preferred orientation effect, impurity). Finally, the crystal structure has been derived from powder data with a precision probably sufficient for most purposes.

The ternary nitridotungstate Li6WN4 has been synthesized via the solid state reaction of lithium subnitride, Li3N, with W under nitrogen. High quality X-ray powder diffraction data were collected for the crystal-structure determination. Li6WN4 crystallizes in the tetragonal system, space group P42∕nmc, with cell parameters a=6.6759(3) Å and c=4.9280(3) Å, Z=2. Preliminary thermal stability measurements of Li6WN4 show that it is sensitive to moisture, even at room temperature, and decomposes at high temperatures below 1000 °C under flowing nitrogen.

The high cohesive interaction between reduced graphene oxide (RGO) sheets usually makes them difficult to disperse, which limits their utilization in achieving effective hybridization with polymers. We report here a new two-step route for preparing non-aggregated and high-conductive RGO powders. Graphene oxide precursor was first reduced by hydrazine hydrate in presence of a thermal unstable surfactant of cetyltrimethylammonium chloride (CTAC). Then a thermal annealing process under H2/Ar atmosphere was further used to remove the non-conductive CTAC molecules. The prepared RGO powder exhibited an electrical conductivity of 2.23 × 104 S m−1 – about ten times higher than the one (N-RGO) simply reduced by hydrazine hydrate. After incorporating into polymethylmethacrylate with a 5 wt% loading, the composite showed a conductivity of 4.11 S m−1, which was 60 times as high as that of the same composite based on N-RGO powder. The addition and subsequent removal of CTAC molecules is an effective method for preparing non-aggregated and highly conductive graphene powder and obtaining good incorporation into polymer matrices.

The laboratory implementation of grazing incidence in-plane X-ray diffraction, using an unmodified commercial diffractometer, is described. Low resolution, high intensity measurements are illustrated in the study of the in-plane lattice parameters and texture of a thin polycrystalline ZnO film on glass, the in-plane order in Cd arachidate Langmuir–Blodgett films, and the depth dependence of the lattice parameter in graded Si–Ge epilayers. Use of an asymmetrically cut Ge crystal to compress and monochromate the beam provides a high resolution setting, appropriate to measurement of the in-plane mosaic of mismatched epilayers such as GaN on sapphire.

A new ternary compound Gd117Fe52Ge112 has been successfully synthesized and studied by means of X-ray powder diffraction technique. Gd117Fe52Ge112 crystallizes in a cubic Tb117Fe52Ge112-type structure with space group Fm3m(#225) and lattice parameter a=28.7680(1) Å. Crystal structure of Gd117Fe52Ge112 has been successfully refined using the Rietveld method from X-ray diffraction data. The R-factors for the Rietveld refinement are Rp=0.099 and Rwp=0.128. X-ray powder diffraction data with the figure of merit F30 of 80.4(30) are also reported.