scholarly journals Identification of preferentially exposed crystal facets by X-ray diffraction

RSC Advances ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 5585-5589 ◽  
Author(s):  
Liping Zhang ◽  
Alexandre A. S. Gonçalves ◽  
Mietek Jaroniec
Keyword(s):  
Preferred Orientation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Peaks ◽  
Exposed Facets ◽  
Anisotropic Nanostructures

Intensification of X-ray diffraction peaks can be used to get information about doping, presence of vacancies, anisotropic nanostructures, or preferred orientation of crystals with largely exposed facets.

scholarly journals The suppression of fluorescence peaks in energy-dispersive X-ray diffraction

2014 ◽  
Vol 47 (5) ◽  
pp. 1708-1715 ◽  
Author(s):  
G. M. Hansford ◽  
S. M. R. Turner ◽  
D. Staab ◽  
D. Vernon
Keyword(s):  
Excitation Energy ◽  
Preferred Orientation ◽  
Energy Dispersive ◽  
Source Spectrum ◽  
Natural State ◽  
X Ray Diffraction ◽  
Scattering Angle ◽  
X Ray ◽  
Back Reflection ◽  
Diffraction Peaks

A novel method to separate diffraction and fluorescence peaks in energy-dispersive X-ray diffraction (EDXRD) is described. By tuning the excitation energy of an X-ray tube source to just below an elemental absorption edge, the corresponding fluorescence peaks of that element are completely suppressed in the resulting spectrum. SinceBremsstrahlungphotons are present in the source spectrum up to the excitation energy, any diffraction peaks that lie at similar energies to the suppressed fluorescence peaks are uncovered. This technique is an alternative to the more usual method in EDXRD of altering the scattering angle in order to shift the energies of the diffraction peaks. However, in the back-reflection EDXRD technique [Hansford (2011).J. Appl. Cryst.44, 514–525] changing the scattering angle would lose the unique property of insensitivity to sample morphology and is therefore an unattractive option. The use of fluorescence suppression to reveal diffraction peaks is demonstrated experimentally by suppressing the Ca Kfluorescence peaks in the back-reflection EDXRD spectra of several limestones and dolomites. Three substantial benefits are derived: uncovering of diffraction peak(s) that are otherwise obscured by fluorescence; suppression of the Ca Kescape peaks; and an increase in the signal-to-background ratio. The improvement in the quality of the EDXRD spectrum allows the identification of a secondary mineral in the samples, where present. The results for a pressed-powder pellet of the geological standard JDo-1 (dolomite) show the presence of crystallite preferred orientation in this prepared sample. Preferred orientation is absent in several unprepared limestone and dolomite rock specimens, illustrating an advantage of the observation of rocks in their natural state enabled by back-reflection EDXRD.

Fast quantitative analysis of strong uniaxial texture using a March–Dollase approach

2013 ◽  
Vol 46 (6) ◽  
pp. 1877-1879 ◽  
Author(s):  
Emil Zolotoyabko
Keyword(s):  
Quantitative Analysis ◽  
Intensity Ratio ◽  
Preferred Orientation ◽  
Diffraction Peak ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Diffraction Peaks ◽  
Analytical Expressions

Interrelations between the degree of uniaxial preferred orientation and the intensities and widths of selected X-ray diffraction peaks are analyzed within the March–Dollase approach. Simple analytical expressions are developed which relate the degree of preferred orientation to the rocking curve width of the strongest diffraction peak or the intensity ratio of two diffraction peaks, one of them being originated in the preferably orientated atomic planes.

PREPARATION AND PROPERTIES OF AlPdRe ICOSAHEDRAL QUASICRYSTALLINE THIN FILMS BY MOLECULAR BEAM EPITAXY

2002 ◽  
Vol 01 (05n06) ◽  
pp. 527-531
Author(s):  
KAZUHIRO KIRIHARA ◽  
KENJI KAWAGUCHI ◽  
NAOTO KOSHIZAKI ◽  
KAORU KIMURA
Keyword(s):  
Thin Films ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Preferred Orientation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Post Annealing ◽  
Icosahedral Quasicrystals ◽  
Diffraction Peaks ◽  
Icosahedral Quasicrystalline

We obtained thin films of the AlPdRe icosahedral quasicrystals by molecular beam epitaxy and post-annealing. The thickness of the films was estimated to be smaller than 100 nm. Any preferred orientation in the X-ray diffraction peaks was not observed in the films.

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

Comparative Studies of Ultra Low-κ Porous Silica Films with 2-D Hexagonal and Disordered Pore Structures

2004 ◽  
Vol 812 ◽  
Author(s):  
Nobutoshi Fujii ◽  
Kazuhiro Yamada ◽  
Yoshiaki Oku ◽  
Nobuhiro Hata ◽  
Yutaka Seino ◽  
...  
Keyword(s):  
Pore Structure ◽  
Nonionic Surfactants ◽  
Porous Silica ◽  
Silica Film ◽  
X Ray Diffraction ◽  
Silica Films ◽  
X Ray ◽  
X Ray Scattering ◽  
Porous Silica Film ◽  
Diffraction Peaks

AbstractPeriodic 2-dimensional (2-D) hexagonal and the disordered pore structure silica films have been developed using nonionic surfactants as the templates. The pore structure was controlled by the static electrical interaction between the micelle of the surfactant and the silica oligomer. No X-ray diffraction peaks were observed for the disordered mesoporous silica films, while the pore diameters of 2.0-4.0 nm could be measured by small angle X-ray scattering spectroscopy. By comparing the properties of the 2-D hexagonal and the disordered porous silica films which have the same porosity, it is found that the disordered porous silica film has advantages in terms of the dielectric constant and Young's modulus as well as the hardness. The disordered porous silica film is more suitable for the interlayer dielectrics for ULSI.

The Microstructure and Electrical Property of Porous Cu Film on Soft PVDF Substrate

2012 ◽  
Vol 472-475 ◽  
pp. 1451-1454
Author(s):  
Xue Hui Wang ◽  
Wu Tang ◽  
Ji Jun Yang
Keyword(s):  
Electrical Properties ◽  
Film Surface ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
X Ray ◽  
Cu Films ◽  
Cu Film ◽  
Diffraction Peaks ◽  
Sputtering Pressure ◽  
Effect Method

The porous Cu film was deposited on soft PVDF substrate by magnetron sputtering at different sputtering pressure. The microstructure and electrical properties of Cu films were investigated as a function of sputtering pressure by X-ray diffraction XRD and Hall effect method. The results show that the surface morphology of Cu film is porous, and the XRD revealed that there are Cu diffraction peaks with highly textured having a Cu-(220) or a mixture of Cu-(111) and Cu-(220) at sputtering pressure 0.5 Pa. The electrical properties are also severely influenced by sputtering pressure, the resistivity of the porous Cu film is much larger than that fabricated on Si substrate. Furthermore, the resistivity increases simultaneously with the increasing of Cu film surface aperture, but the resistivity of Cu film still decreases with the increasing grain size. It can be concluded that the crystal structure is still the most important factor for the porous Cu film resistivity.

Synthesis and Properties of Thermotropic Liquid Crystalline Polyesters with Flexible Polymethylene Spacer

2010 ◽  
Vol 428-429 ◽  
pp. 126-131
Author(s):  
Wei Zhong Lu ◽  
Chun Wei ◽  
Qui Shan Gao
Keyword(s):  
Optical Microscopy ◽  
Liquid Crystalline ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Structure Morphology ◽  
Temperature Ranges ◽  
Ft Ir ◽  
Diffraction Peaks ◽  
Ubbelohde Viscometer

Polymethylene bis(p-hydroxybenzoates) were prepared from methyl p-hydroxybenzoate and different diols by melted transesterification reaction. Three liquid crystalline polyesters were synthesized from terephthaloyl dichloride and polymethylene bis(p-hydroxybenzoates). Its structure, morphology and properties were characterized by Ubbelohde viscometer, Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC), polarized optical microscopy (POM) with a hot stage, and wide-angle X-ray diffraction (WAXD). Results indicated that the intrinsic viscosities were between 0.088 and 0.210 dL/g. Optical microscopy showed that the TLCP has a highly threaded liquid crystalline texture and a high birefringent schlieren texture character of nematic phase and has wider mesophase temperature ranges for all polyesters. DSC analysis were found that the melting point (Tm), isotropic temperature (Ti) of TLCPs decreased and the temperature range of the liquid crystalline phase became wider with increased number of methylene spacers in the polyester. The WAXD results showed that TLCPs owned two strong diffraction peaks at 2θ near 19° and 23°.

NbN Thin Film of Alternating Textures

2017 ◽  
Vol 898 ◽  
pp. 1431-1437
Author(s):  
Hong Yang Shao ◽  
Kan Zhang ◽  
Yi Dan Zhang ◽  
Mao Wen ◽  
Wei Tao Zheng
Keyword(s):  
Deposition Time ◽  
Peak Position ◽  
Preferred Orientation ◽  
Intrinsic Stress ◽  
Competitive Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Orientation Distributions ◽  
Different Thickness ◽  
Deposited Films

The δ-NbN thin films with different thickness have been prepared by reactive magnetron sputtering at different deposition time and exhibited alternating textures between (111) and (200) orientations as a function of thickness. In addition, the grain size, peak position, morphology, residual stress and orientation distributions of the deposited films were explored by X-ray diffraction, low-angel X-ray reflectivity, scanning electron microscopy and surface profiler. The film deposited at 300 s showed a (111) preferred orientation, changing to (200) preferred orientation at 600 s, and exhibited alternating textures between (111) and (200) preferred orientations. With further increasing deposition time, in which (200) peak position and the full width at half maximum of (111) peak also displayed a trend of alternating variation with varying deposition time. The intrinsic stress for δ-NbN films calculated by Stoney equation alternately changed with alternating textures, in which (111) orientation always takes place at relatively high intrinsic stress state and vice versa. Meanwhile, the film with (111) preferred orientation showed higher density than (200) preferred orientation. The film deposited at 4800 s owned a mixed texture of (111) and (200), showing an anisotropy distribution of (111)-oriented and (200)-oriented grains, while film deposited at 7200 s owned a strong (200) texture, displaying an isotropy distribution of (200)-oriented grains. The competitive growth between (111)-oriented and (200)-oriented grains was responsibility for alternating texture.

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