scholarly journals Unusual Breathing Behavior of Optically Excited Barium Titanate Nanocrystals

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 365
Author(s):  
Jiecheng Diao ◽  
Mathew Cherukara ◽  
Ross Harder ◽  
Xiaojing Huang ◽  
Fucai Zhang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Barium Titanate ◽  
Free Electron Laser ◽  
Laser Excitation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Contacts ◽  
Diffraction Peaks ◽  
Diffraction Patterns ◽  
Transfer Direction

Coherent X-ray diffraction patterns were recorded by using an X-ray free-electron laser to illuminate barium titanate nanocrystals as a function of time delay after laser excitation. Rather than seeing any significant thermal expansion effects, the diffraction peaks were found to move perpendicular to the momentum transfer direction. This suggests a laser driven rotation of the crystal lattice, which is delayed by the aggregated state of the crystals. Internal deformations associated with crystal contacts were also observed.

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.

Structural properties of molecular beam epitaxy grown Ni/Pt superlattices

1997 ◽  
Vol 12 (1) ◽  
pp. 161-174 ◽  
Author(s):  
W. Staiger ◽  
A. Michel ◽  
V. Pierron-Bohnes ◽  
N. Hermann ◽  
M. C. Cadeville
Keyword(s):  
Molecular Beam ◽  
Growth Direction ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Superlattice Peak ◽  
Diffraction Peaks ◽  
Diffraction Patterns

We find that the [Ni3.2nmPt1.6nm] × 15 and [Ni3.2nmPt0.8nm] × 15 multilayers are semicoherent and display a columnar morphology. From both the period of the moir’e fringes and the positions of the diffraction peaks in electronic (plan-view and crosssection geometries) and x-ray diffraction patterns, one deduces that the nickel is relaxed (at least in the error bars of all our measurements), whereas the platinum remains slightly strained (≈−1%). The interfaces are sharp; no intermixing takes place giving rise to neat contrasts in transmission electron microscopy (TEM) and to high intensities of the superlattice peaks in the growth direction in both diffraction techniques. The relaxation of the interfacial misfit occurs partially through misfit dislocations, partially through the strain of platinum. A quasiperiodic twinning occurs at the interfaces, the stacking fault which forms the twin being the most often located at the interface Pt/Ni, i.e., when a Pt layer begins to grow on the Ni layer. The simulation of the θ/2θ superlattice peak intensities takes into account the columnar microstructure. It shows that the roughness is predominantly at medium scale with a fluctuation of about 12.5% for Ni layers and negligible for Pt layers.

scholarly journals FELIX: an algorithm for indexing multiple crystallites in X-ray free-electron laser snapshot diffraction images

2017 ◽  
Vol 50 (4) ◽  
pp. 1075-1083 ◽  
Author(s):  
Kenneth R. Beyerlein ◽  
Thomas A. White ◽  
Oleksandr Yefanov ◽  
Cornelius Gati ◽  
Ivan G. Kazantsev ◽  
...  
Keyword(s):  
Free Electron Laser ◽  
Signal To Noise Ratio ◽  
X Ray Diffraction ◽  
Signal To Noise ◽  
Monoclinic Crystal ◽  
Slight Tendency ◽  
X Ray ◽  
Serial Crystallography ◽  
Diffraction Patterns ◽  
Novel Algorithm

A novel algorithm for indexing multiple crystals in snapshot X-ray diffraction images, especially suited for serial crystallography data, is presented. The algorithm, FELIX, utilizes a generalized parametrization of the Rodrigues–Frank space, in which all crystal systems can be represented without singularities. The new algorithm is shown to be capable of indexing more than ten crystals per image in simulations of cubic, tetragonal and monoclinic crystal diffraction patterns. It is also used to index an experimental serial crystallography dataset from lysozyme microcrystals. The increased number of indexed crystals is shown to result in a better signal-to-noise ratio, and fewer images are needed to achieve the same data quality as when indexing one crystal per image. The relative orientations between the multiple crystals indexed in an image show a slight tendency of the lysozme microcrystals to adhere on (\overline 110) facets.

scholarly journals Data processing software suiteSITENNOfor coherent X-ray diffraction imaging using the X-ray free-electron laser SACLA

2014 ◽  
Vol 21 (3) ◽  
pp. 600-612 ◽  
Author(s):  
Yuki Sekiguchi ◽  
Tomotaka Oroguchi ◽  
Yuki Takayama ◽  
Masayoshi Nakasako
Keyword(s):  
Data Processing ◽  
Free Electron ◽  
Free Electron Laser ◽  
Single Shot ◽  
X Ray Diffraction ◽  
X Ray ◽  
Custom Made ◽  
Diffraction Imaging ◽  
Diffraction Patterns ◽  
Ccd Detectors

Coherent X-ray diffraction imaging is a promising technique for visualizing the structures of non-crystalline particles with dimensions of micrometers to sub-micrometers. Recently, X-ray free-electron laser sources have enabled efficient experiments in the `diffraction before destruction' scheme. Diffraction experiments have been conducted at SPring-8 Angstrom Compact free-electron LAser (SACLA) using the custom-made diffraction apparatus KOTOBUKI-1 and two multiport CCD detectors. In the experiments, ten thousands of single-shot diffraction patterns can be collected within several hours. Then, diffraction patterns with significant levels of intensity suitable for structural analysis must be found, direct-beam positions in diffraction patterns determined, diffraction patterns from the two CCD detectors merged, and phase-retrieval calculations for structural analyses performed. A software suite namedSITENNOhas been developed to semi-automatically apply the four-step processing to a huge number of diffraction data. Here, details of the algorithm used in the suite are described and the performance for approximately 9000 diffraction patterns collected from cuboid-shaped copper oxide particles reported. Using theSITENNOsuite, it is possible to conduct experiments with data processing immediately after the data collection, and to characterize the size distribution and internal structures of the non-crystalline particles.

scholarly journals Specimen preparation for cryogenic coherent X-ray diffraction imaging of biological cells and cellular organelles by using the X-ray free-electron laser at SACLA

2016 ◽  
Vol 23 (4) ◽  
pp. 975-989 ◽  
Author(s):  
Amane Kobayashi ◽  
Yuki Sekiguchi ◽  
Tomotaka Oroguchi ◽  
Koji Okajima ◽  
Asahi Fukuda ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
X Ray Diffraction ◽  
X Ray ◽  
Internal Structures ◽  
Thin Membranes ◽  
Diffraction Imaging ◽  
Diffraction Patterns ◽  
Cellular Organelles

Coherent X-ray diffraction imaging (CXDI) allows internal structures of biological cells and cellular organelles to be analyzed. CXDI experiments have been conducted at 66 K for frozen-hydrated biological specimens at the SPring-8 Angstrom Compact Free-Electron Laser facility (SACLA). In these cryogenic CXDI experiments using X-ray free-electron laser (XFEL) pulses, specimen particles dispersed on thin membranes of specimen disks are transferred into the vacuum chamber of a diffraction apparatus. Because focused single XFEL pulses destroy specimen particles at the atomic level, diffraction patterns are collected through raster scanning the specimen disks to provide fresh specimen particles in the irradiation area. The efficiency of diffraction data collection in cryogenic experiments depends on the quality of the prepared specimens. Here, detailed procedures for preparing frozen-hydrated biological specimens, particularly thin membranes and devices developed in our laboratory, are reported. In addition, the quality of the frozen-hydrated specimens are evaluated by analyzing the characteristics of the collected diffraction patterns. Based on the experimental results, the internal structures of the frozen-hydrated specimens and the future development for efficient diffraction data collection are discussed.

Comments on determining X-ray diffraction-based volume fractions of retained austenite in steels

2001 ◽  
Vol 16 (4) ◽  
pp. 198-204 ◽  
Author(s):  
C. K. Lowe-Ma ◽  
W. T. Donlon ◽  
W. E. Dowling
Keyword(s):  
Retained Austenite ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Profile Fitting ◽  
Diffraction Peaks ◽  
Diffraction Patterns ◽  
Heat Treatment Regimes ◽  
Integrated Intensities

Retained austenite is an important characteristic of properly heat-treated steel components, particularly gears and shafts, that will be subjected to long-term use and wear. Normally, either X-ray diffraction or optical microscopy techniques are used to determine the volume percent of retained austenite present in steel components subjected to specific heat-treatment regimes. As described in the literature, a number of phenomenological, experimental, and calculation factors can influence the volume fraction of retained austenite determined from X-ray diffraction measurements. However, recent disagreement between metallurgical properties, microscopy, and service laboratory values for retained austenite led to a re-evaluation of possible reasons for the apparent discrepancies. Broad, distorted X-ray peaks from un-tempered martensite were found to yield unreliable integrated intensities whereas diffraction peaks from tempered samples were more amenable to profile fitting with standard shape functions, yielding reliable integrated intensities. Retained austenite values calculated from reliable integrated intensities were found to be consistent with values obtained by Rietveld refinement of the diffraction patterns. The experimental conditions used by service laboratories combined with a poor choice of diffraction peaks were found to be sources of retained austenite values containing significant bias.

Powder diffraction analysis of an interstratified marcasite/pyrite structure

1995 ◽  
Vol 10 (3) ◽  
pp. 198-203 ◽  
Author(s):  
Neil E. Johnson ◽  
Sidney S. Pollack ◽  
Elizabeth A. Frommell ◽  
Patricia A. Eldredge
Keyword(s):  
Catalytic Activity ◽  
Stacking Faults ◽  
Catalyst Precursor ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Naturally Occurring ◽  
Benzylic Carbon ◽  
Diffraction Peaks ◽  
Diffraction Patterns

A synthetic catalyst precursor formed by sulfiding ferrihydrite (Fe3+O(OH)) in the presence of a hydrogen donor produces X-ray diffraction patterns resembling a mixture of both naturally occurring FeS2 polymorphs marcasite and pyrite. The diffraction peaks display a differential broadening, however, wherein only those peaks coincident to both marcasite and pyrite are strong and sharp, a feature that cannot be accounted for by a simple physical mixture. The broadening is analogous to that found in hexagonal cobalt, where occasional stacking faults produce interstratification of the hexagonal and cubic close-packed forms, resulting in strongly coherent diffraction only along the stacking direction. The crystal structures of marcasite and pyrite are virtually identical if viewed perpendicular to the (101) and (001) planes, respectively. Calculation of diffraction patterns based upon models of interstratifying marcasite and pyrite layers along these planes demonstrates that a sequence with marcasite-to-pyrite and pyrite-to-marcasite stacking fault probabilities of 0.22 provides a good fit to the experimental pattern. This interstratified material is a precursor to a species that shows catalytic activity for cleaving C-C bonds between aromatic rings and benzylic carbon atoms at low (<350 °C) temperatures.

scholarly journals ANALISIS KARAKTERISASI XRD SINTESIS GADOLINIUM KARBONAT (Gd2(CO3)3@PEG DENGAN METODE SOLVOTERMAL

2019 ◽  
Vol 5 (1) ◽  
pp. 29-32
Author(s):  
Erika Linda Yani Nasution
Keyword(s):  
Solvothermal Method ◽  
Heating Time ◽  
Main Peak ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sample Heating ◽  
Degree Of Crystallization ◽  
Diffraction Peaks ◽  
Diffraction Patterns

Abstrak Telah dilakukan sintesis partikel pegilasi gadolinium karbonat dengan metode solvotermal menggunakan prekursor polietilen glikol (PEG-1000) dan gadolinium asetat hidrat (Gd(CH3CO3)3) pada suhu 180oC dengan waktu pemanasan selama 3 jam, 5 jam, dan 7 Jam. Partikel pegilasi gadolinium karbonat (Gd2(CO3)3@PEG tersebut selanjutnya dianalisis pola difraksi dan bentuk struktur dengan menggunakan X-Ray Diffraction (XRD). Hasil karakterisasi spektrum XRD terhadap partikel Gd2(CO3)3 menunjukkan pila difraksi dengan posisi puncak-puncak difraksi bersesuaian dengan JCPDS No. 37-0559 dengan puncak utama pada 2θ = 11.75o.  Pada waktu  pemanasan 3 jam , sampel memiliki sifat amorf, sedangkan pada sampel waktu pemanasan 5 jam dan 7 jam sampel-sampel memiliki derajat kekristalan yang baik. Pada waktu pemanasan 5 jam lebih tinggi kristalisasinya daripada 7 jam yang mengindikasikan kualitas kristal lebih baik pada lama pemanasan 5 jam.   Kata kunci : Gadolinium karbonat, metode solvotermal, PEG, XRD   Abstract   [Title: Analysis of XRD Characterization of Gadolinium Carbonate (Gd2 (CO3) 3 @ PEG Synthesis by Solvothermal Method] Synthesis of pegylated gadolinium carbonate particles by solvothermal method using polyethylene glycol (PEG-1000) and gadolinium acetate hydrate (Gd (CH3CO3) 3) precursors at 180oC with heating time for 3 hours, 5 hours and 7 hours. The gadolinium carbonate (Gd2 (CO3) 3 @ PEG particle pegylation was further analyzed by diffraction patterns and structural shapes using X-Ray Diffraction (XRD). The results of XRD spectrum characterization of Gd2 (CO3) 3 particles showed diffraction pila with diffraction peaks position. corresponds to JCPDS No. 37-0559 with the main peak at 2θ = 11.75 o At 3 hours of heating, the sample has amorphous properties, while the sample heating time is 5 hours and 7 hours the samples have a good degree of crystallization. 5 hours higher crystallization than 7 hours which indicates better crystal quality at 5 hours heating time.   Keywords: Gadolinium carbonate, solvothermal method, PEG, XRD

Crystallization of barium titanate thin films synthesized via sol-gel processing

1995 ◽  
Vol 53 ◽  
pp. 258-259
Author(s):  
M. C. Gust ◽  
N. D. Evans ◽  
M. L. Mecartney
Keyword(s):  
Thin Films ◽  
Barium Titanate ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Independent Films ◽  
X Ray ◽  
Fine Grained ◽  
Diffraction Patterns ◽  
Gel Processing ◽  
Alkoxide Precursors

Sol-gel processing of oxide thin films offers the potential to generate different microstructures by varying process parameters such as water of hydrolysis, chemical precursor, or substrate. For this work, barium titanate (BaTiO3) thin films were prepared by the sol-gel method in order to try and generate different microstructures for dielectric measurements. However, for BaTiOs prepared using alkoxide precursors, the final microstructures of the films were found to be almost process independent. Films using different precursors, different substrates, and different amounts of water of hydrolysis all showed similar TEM microstructures. All the films after final heat treatment were polycrystalline, nanoporous, and randomly oriented BaTiO3; they were also fine-grained, with an average uniform grain size of 25-50 nm (Fig. 1). This fine-grained microstructure has also been observed in other studies of sol-gel derived BaTiO3 thin films. In addition to BaTiO3, electron diffraction patterns showed the presence of trace amounts of rutile TiO2 that were not observed by x-ray diffraction (XRD).

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