The microstructure of materials is generally, macroscopically, anisotropic and/or inhomogeneous. Traditional diffraction analyses do not take into account this anisotropy and/or inhomogeneity of microstructural features. Thus obtained results can be incomplete, ambiguous, or even erroneous. In this work instrumental requirements (application of parallel beam diffractometers with X-ray lenses or X-ray mirrors and parallel-plate collimators in the laboratory and at synchrotron beam lines) and methodological approaches for the diffraction analysis of anisotropic and inhomogeneous microstructures have been discussed and have been illustrated on the basis of two experimental examples: analysis of the anisotropic nature of the structural imperfection of a sputterdeposited Ti3Al layer and analysis of the anisotropic and inhomogeneous elastic grain interaction in a sputter-deposited Ni layer.

The Monte Carlo—Library Least-Squares (MCLLS) approach has now been developed, implemented, and tested for solving the inverse problem of EDXRF sample analysis. It consists of a linear library least-squares code and a comprehensive Monte Carlo code named CEARXRF that is capable of calculating the unknown sample spectrum, all the elemental library spectra in the sample, and the differential operators for each library spectrum with respect to each element. Two codes with graphical user interface have been designed to implement the MCLLS approach and benchmark results are presented for the two stainless steel samples; SS304 and SS316. The results are accurate, the system is easy to use, and all indications are that this approach will be very useful for the EDXRF practitioner.

A revised structure model of ettringite is presented, in order to provide quantitative X-ray diffraction (QXRD) of this mineral in cement pastes. The model is derived from two different existing structure models, both of which are suitable for restricted use but are inferior to the refined ettringite structure presented. In the first published ettringite structure proposed by Moore and Taylor [Acta Crystallogr. B 26, 386–393 (1970)], none of the 128 positions for H are given in the unit cell, which results in reduced scattering power for use of this model for quantification purposes. For the precise quantification of ettringite in samples together with anhydrous phases, the scattering factors of all atoms including the H positions are indispensable. The revised structure model is based on the data of Moore and Taylor, supplemented by the H positions determined by Berliner (Material Science of Concrete Special Volume, The Sydney Diamond Symposium, American Ceramic, Society, 1998, pp. 127–141) on the basis of a neutron diffraction structural investigation of deuterated ettringite at 20 K. Berliner’s (Material Science of Concrete Special Volume, The Sydney Diamond Symposium, American Ceramic Society, 1998, pp. 127–141) thermal parameter should not, however, be used, since a normal application is at room temperature. In order further to improve the structure model of ettringite, Rietveld refinement with the rigid body approach for OH and H2O molecules and SO4 tetrahedra was employed. The refined and improved ettringite structure model was tested for quantitative phase analysis by the determination of actual ettringite contents in mixtures with an internal standard. Synthesized and orientation-free prepared ettringite powders were investigated by X-ray powder diffraction analysis and quantified in four different blends with zircon. The quantification results with the new structure model demonstrate the superior quality of the revised ettringite structure.

Crystal structure of a new compound KBaB5O9 has been investigated from X-ray powder diffraction data. This compound is isostructural with KSrB5O9 and crystallizes in the monoclinic system with space group P21/c. Unit-cell parameters are a=6.7200(2) Å, b=8.3256(2) Å, c=14.3674(4) Å, and β=92.6103(3) deg. Its structure contains both B3O7 and B3O8 rings, which share a common B atom to form a complex two dimensional network constituting the basic B5O9 unit in the formula. Adjacent networks are bound together by Ba and K atoms, which have eight- and nine-coordinate sites, respectively. In addition, DTA and TGA curves reveal that KBaB5O9 decomposes at 798 °C. Photoluminescence (PL) characteristics of KBaB5O9:Eu3+ have been studied. The PL spectra show the strongest emission at 618 nm and the quench concentration of Eu3+ is 4 at. %.

As complementary metal oxide semiconductor devices continue to scale along the rapid pace of Moore’s law, gate dielectric materials with significantly higher dielectric constant (k=10–25) are being evaluated as replacements for conventional silicon dioxide, SiO2 (k=3.9), and silicon oxynitride. This allows for the introduction of a physically thicker film with lower leakage current and with capacitance equivalent to a thinner (1.0 nm and below) SiO2 layer (Schlom and Haeni, 2002; Wilk et al., 2001; Kingon et al., 2001). Although binary metal oxide films such as HfO2 and ZrO2 exhibit higher permittivity than their corresponding silicates and aluminates, alloyed with various molecular percents of SiO2 or Al2O3, respectively, they are compromised by lower onset of crystallization temperature which contributes a higher degree of interfacial microroughness and increased gate leakage current due to dislocations and oxygen vacancies generated along grain boundaries. Accordingly, development of hafnium silicate has been the subject of intense investigation as an advanced gate dielectric thin film designed to meet the device manufacturing requirements of thermal stability in direct contact with substrate silicon and metal gate electrode materials. In this paper, we present results corresponding to the utilization of total reflection X-ray fluorescence spectroscopy (TXRF) as a quick, accurate, nondestructive technique for hafnium silicate composition determination based on detection of the Hf:Si ratio of (HfO2)x(SiO2)1−x, where x varies over the range 0.2–1.0.

An electron probe X-ray microanalysis (EPMA) technique using an energy-dispersive X-ray detector with an ultrathin window, designated low-Z particle EPM, has been developed. The low-Z particle EPMA allows the quantitative determination of concentrations of low-Z elements, such as C, N, and O, as well as higher-Z elements that can be analyzed by conventional energy-dispersive EPMA. The quantitative determination of low-Z elements (using full Monte Carlo simulations, from the electron impact to the X-ray detection) in individual environmental particles has improved the applicability of single-particle analysis, especially in atmospheric environmental aerosol research; many environmentally important atmospheric particles, e.g. sulfates, nitrates, ammonium, and carbonaceous particles, contain low-Z elements. The low-Z particle EPMA was applied to characterize loess soil particle samples of which the chemical compositions are well defined by the use of various bulk analytical methods. Chemical compositions of the loess samples obtained from the low-Z particle EPMA turn out to be close to those from bulk analyses. In addition, it is demonstrated that the technique can also be used to assess the heterogeneity of individual particles.

A series of Dy2Co17−xGax polycrystalline samples with x from 0 to 7 were prepared by arc melting. X-ray powder diffraction analysis indicated that these compounds have the hexagonal Th2Ni17 structure for x≤3 and the rhombohedral Th2Zn17 structure for 3.5≤x≤7. The lattice parameters a and c increase linearly with the gallium content until x=5.3. With further increasing the gallium content x up to 7, the lattice parameter c slightly decreases, whereas the lattice parameter a increases more quickly than that for 0≤x≤5.3. The unit-cell volume shows an approximately linear increase of 6.1 Å3/Ga for 0≤x≤3.0 and 10.1 Å3/Ga for 3.5≤x≤7.0, respectively. Rietveld refinement of the Dy2Co11.7Ga5.3 compound reveals that the Ga atoms occupy all the 6c, 9d, 18f, and 18h sites and preferentially occupy the 6c site. The Curie temperature and the saturation magnetization of the rhombohedral Dy2Co17−xGax compounds decrease almost linearly with increasing Ga content.

The crystal structure of recently discovered chromium (III) dimagnesium trivanadate (V) Mg2CrV3O11 was refined using the Rietveld method. The crystal system of Mg2CrV3O11 is triclinic with space group P1− (Mg1.7Zn0.3GaV3O11 type) and lattice parameters a=6.4057(1) Å, b=6.8111(1) Å, c=10.0640(2) Å, α=97.523(1)°, β=103.351(1)°, γ=101.750(1)°, and Z=2. The characteristic feature of compounds in the A2BV3O11 (A=Mg, Zn and B=Ga, Fe, Cr) family is a strong tendency to share the octahedral M(1) and M(2) sites by both divalent A and trivalent B atoms, and the bipyramidal M(3) sites occupied by divalent A ions. In the present refinement, the only constraint assuming full occupancy of the M(1), M(2), and M(3) sites leads to the following Cr/(Cr+Mg) ratios: 0.70(2) at M(1), 0.24(2) at M(2), and 0.03(2) at M(3). These occupancies are discussed and compared to those of isotypic compounds. The values of interatomic distances are found to be comparable with those reported by R. D. Shannon in 1976. Electron paramagnetic resonance has been also analyzed. Two absorption lines with g≈2.0 (type I) and g≈1.98 (type II) have been recorded in the EPR spectra, and attributed to V4+ ions and Cr3+–Cr3+ ion pairs, respectively. The exchange constant J between Cr3+ ions has been calculated.

X-ray powder diffraction data are presented for nine new phases with the tetragonal tungsten bronze structure. By comparison with the structure of the M=Nb,RE=La analogue, these contain Ba in the large pentagonal sites with coordination number 15, a range of large rare-earth cations and Bi in the twelve coordinate sites, and the smaller cations, Ti and either Nb or Ta, in the octahedral framework sites. The a lattice parameter data of the tetragonal unit cell show an approximately linear variation with trivalent ion radius, apart from Dy, whose value appears to be anomalous; data for c show little variation with trivalent ion radius.

We know a lot about normal values of bond distances, bond angles, torsion angles, and other molecular parameters. This knowledge can be incorporated into the structure solution process and into Rietveld refinement through the use of restraints and rigid bodies. An important measure of the quality of the refined model is the chemical reasonableness of molecular geometry. Refinement of the structures of calcium tartrate tetrahydrate and guaifenesin is used to illustrate the importance of chemical reasonableness in determining the quality of a Rietveld refinement.

Complexes of 1,8-bis(dimethylamino)naphthalene, known also as DMAN, with phthalic acid, terephthalic acid, and 5-aminoisophthalic acid were synthesized and investigated by means of powder diffraction methods. DMAN and phthalic acid complexes crystallize in the orthorhombic system, space group Pnmm (59) with the lattice parameters a=1.17423(3) nm, b=1.7124(4) nm, c=0.9933(4) nm, V=1.997 24 nm3, whereas DMAN complexes with terephthalic acid or 5-aminoisophthalic acid crystallize in the monoclinic system in the space group P2 or P2∕m with the lattice parameters a=2.4337(5) nm, b=0.9665(2) nm, c=1.1800(3) nm, β=91.53(2)°, V=2.774 51 nm3 and a=2.1609(7) nm, b=1.1017(6) nm, c=1.8921(7) nm, β=112.095(34)°, V=4.173 46 nm3, respectively.

X-ray powder diffraction data for N,N'-diphenylguanidinium nitrate, within the temperature range of 103–293 K, are reported. The pattern at 293 K was confirmed by a fitting of the overall parameters performed with FULLPROF using the atomic parameters obtained from single-crystal studies. The compound is orthorhombic, space group Pna21 (33), with unit-cell parameters a=1.7058(4) nm, b=1.3933(3) nm, c=0.5821(1) nm, and V=1.3834(6) nm3. The unit-cell parameters for the other six temperatures measured were determined by performing pattern matching with FULLPROF. The unit-cell volume contracted on cooling from 1.3834(6) nm3 to 1.3403(4) nm3. The thermal expansion tensor was calculated from the changes of the unit-cell parameters with temperature. The elements of the thermal expansion tensor at 293 K are α11=125(4),α22=57(9), and α33=82(3)×10−6 K−1.

Thin-walled heat-shrink poly(ethylene terephthalate) (PET) tubing is reported for use as an alternative for glass and Kapton® capillaries. PET tubing displays properties such as low X-ray absorption and smooth diffraction profiles. The 2.0 mm thin-walled (0.05 mm thick) and 0.5 mm thin-walled (0.02 mm thick) heat-shrink PET capillaries are 86% and 96% transparent to 1.54 Å X-rays. The low X-ray absorption and relatively smooth X-ray scattering profile of PET make it an ideal material for the home laboratory where the long wavelength, low flux, and low brilliance X-ray sources are employed. PET capillaries can be easily cut and manipulated and fixed to copper pins, which in turn can be employed in low-temperature and automated data collection routines.

A study examining the feasibility, and possible necessity, of using transmission data from capillary mounted samples for quantitative analysis of hydrated cement systems was conducted. In order to obtain true quantitative results, the amorphous contents were determined by the addition of an internal standard. The amorphous content of the starting tricalcium silicate was found to be approximately 21–22 wt %, in close agreement with previously published results. The study revealed that the spherical harmonics preferential orientation correction may not be reliable with unmicronized hydrated cement materials in reflection geometry, as chemically unreasonable progressions in Portlandite content with time were observed. The data obtained from capillary measurements, however, exhibited little or no preferential orientation, and appeared to produce the progression of phase contents expected from the reaction. The use of capillaries would appear to be justified in some circumstances to obtain reliable quantitative results from hydrated cementitious materials. In this particular system, a significant fraction of calcium carbonate was present as aragonite, as well as the more usual calcite.