High Density Bulk Shape Rapid Consolidation of the Yba2Cu307-X Superconductor

1989 ◽  
Vol 169 ◽  
Author(s):  
S. V. Rele ◽  
R. V. Raman ◽  
H. S. Meeks ◽  
R. L. Anderson ◽  
R. N. Shelton ◽  
...  
Keyword(s):  
Volume Fraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Superconducting Volume Fraction ◽  
One Step ◽  
Hollow Cylinders ◽  
Diffraction Patterns ◽  
Set Up ◽  
Cylinders And Spheres ◽  
High Processing

AbstractA novel rapid densification technique for fabrication of bulk shape YBa2Cu307–xsuperconductor is presented. The Ceracon process is a one‐step, quasi‐isostatic consolidation route utilizing conventional P/M equipment and set‐up. The Ceracon technology has enabled successful fabrication of bulk, shapes such as discs, cylinders, hollow cylinders and spheres along with significant increases in the density up to 95‐98% of the theorertical. The superconducting volume fraction is preserved due to short hold times at the operating temperatures and avoidance of high processing temperatures. Results based on densities, microstructure, susceptibility measurements, X‐ray diffraction patterns and TGA measurements are discussed.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Effect of the BSCCO superconducting properties by tiny Y2O3 addition

2016 ◽  
Vol 30 (26) ◽  
pp. 1650328
Author(s):  
Yan Dong ◽  
Aimin Sun ◽  
Bin Xu ◽  
Hongtao Zhang ◽  
Meng Zhang
Keyword(s):  
Volume Fraction ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Critical Transition Temperature ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Oxide Addition ◽  
One Step ◽  
Step Transition ◽  
Y2o3 Addition

In this paper, the effect of tiny Y2O3 addition in (Bi,[Formula: see text]Pb)-2223 superconductor prepared by solid state reaction technique was studied. The properties of samples have been investigated via X-ray diffraction (XRD), resistance–temperature ([Formula: see text]–[Formula: see text]) curve, scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). XRD data indicated that all samples are multiphase and the major phases are high-temperature phases and low-temperature phases. The volume fraction of (Bi,[Formula: see text]Pb)-2223 is not great change with tiny Y2O3 addition. All samples exhibit superconducting phase with the critical transition temperature and one-step transition, however, the transition width was decreased with the Y2O3 addition up to 0.04 wt.% and sharp increased with the excessive oxide addition. SEM pictures show that the Y2O3 appeared on the flake-type grains surface obviously, but the number and size of the hole between grains are decreased in the 0.04 wt.% addition.

MAGNETIC AND TRANSPORT PROPERTIES OFPr0.7Sr0.3MnO3/La0.5Ca0.5MnO3/Pr0.7Sr0.3MnO3TRILAYERS

2012 ◽  
Vol 26 (23) ◽  
pp. 1250132 ◽  
Author(s):  
H. O. WANG ◽  
P. DAI ◽  
H. LIU ◽  
W. S. TAN ◽  
F. XU ◽  
...  
Keyword(s):  
Transport Properties ◽  
Exchange Bias ◽  
Volume Fraction ◽  
Magnetic Phase ◽  
X Ray Diffraction ◽  
High Crystalline Quality ◽  
Metal Insulator ◽  
X Ray ◽  
Diffraction Patterns ◽  
Oriented Single Crystal

All-manganites Pr0.7Sr0.3MnO3/ La0.5Ca0.5MnO3/ Pr0.7Sr0.3MnO3(PSMO/LCMO/PSMO) trilayers were deposited on (001)-oriented single crystal MgO by pulsed laser deposition. The thickness of both PSMO layers was 36 nm while the thickness of LCMO layer varied from 6 to 36 nm. High resolution X-ray diffraction patterns indicated that trilayers were well (001)-oriented grown with high crystalline quality, and that PSMO layers were fully-strain-relaxed while LCMO spacer was partially strained. Studies on transport and magnetic properties of trilayers indicated that metal-insulator transition temperature TMIincreased from 200 K to 260 K and the saturation magnetization was suppressed with decreasing thickness of LCMO spacer from 36 to 6 nm. Transport properties of trilayers are associated with enhancement of volume fraction of ferromagnetic clusters in charge ordered and magnetic phase separated LCMO spacer. Interestingly, exchange bias (EB) was not observed in PSMO/LCMO/PSMO trilayers. It was believed that preferential distribution of metallic ferromagnetic clusters in LCMO layer may result in disappearance of EB.

Shock Wave Compression of NaCl Single Crystals observed by Flash-X-Ray Diffraction

1978 ◽  
Vol 33 (8) ◽  
pp. 918-923 ◽  
Author(s):  
F. Müller ◽  
E. Schulte
Keyword(s):  
Shock Wave ◽  
Single Crystals ◽  
Observation Time ◽  
Plane Shock ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wave Compression ◽  
Shock Wave Compression ◽  
Diffraction Patterns ◽  
Set Up

Flash-x-ray-diffraction patterns (FXD) with an exposure time of 4 ns of NaCl single crystals compressed by plane shock waves are obtained at pressures of about 30 kbar. From the diffraction patterns the compression is determined and compared with Hugoniot data. During shock load the lattice shows an uniaxial compression. While in case of measurements at the free surface an observation time of only a few nanoseconds is available, this experimental set-up allows an observation time of two microseconds.

scholarly journals Zn/F-doped tin oxide nanoparticles synthesized by laser pyrolysis: structural and optical properties

2019 ◽  
Vol 10 ◽  
pp. 9-21 ◽  
Author(s):  
Florian Dumitrache ◽  
Iuliana P Morjan ◽  
Elena Dutu ◽  
Ion Morjan ◽  
Claudiu Teodor Fleaca ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Laser Energy ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Laser Pyrolysis ◽  
One Step ◽  
Diffraction Patterns ◽  
Tin Oxide Nanoparticles ◽  
Co Doped

Zn/F co-doped SnO2 nanoparticles with a mean diameter of less than 15 nm and a narrow size distribution were synthesized by a one-step laser pyrolysis technique using a reactive mixture containing tetramethyltin (SnMe4) and diethylzinc (ZnEt2) vapors, diluted Ar, O2 and SF6. Their structural, morphological, optical and electrical properties are reported in this work. The X-ray diffraction (XRD) analysis shows that the nanoparticles possess a tetragonal SnO2 crystalline structure. The main diffraction patterns of stannous fluoride (SnF2) were also identified and a reduction in intensity with increasing Zn percentage was evidenced. For the elemental composition estimation, energy dispersion X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) measurements were performed. In general, both analyses showed that the Zn percentage increases with increasing ZnEt2 flow, accompanied at the same time by a decrease in the amount of F in the nanopowders when the same SF6 flow was employed. The Raman spectra of the nanoparticles show the influence of both Zn and F content and crystallite size. The fluorine presence is due to the catalytic partial decomposition of the SF6 laser energy transfer agent. In direct correlation with the increase in the Zn doping level, the bandgap of co-doped nanoparticles shifts to lower energy (from 3.55 to 2.88 eV for the highest Zn dopant concentration).

Residual stress measurement on the I12 JEEP beamline at Diamond Light Source

2010 ◽  
Vol 1 (SRMS-7) ◽  
Author(s):  
A. M. Korsunsky ◽  
X. Song ◽  
F. Hofmann ◽  
B. Abbey ◽  
M. Xie ◽  
...  
Keyword(s):  
Light Source ◽  
Stress Measurement ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Loading Direction ◽  
Diffraction Patterns ◽  
Set Up ◽  
Energy Dispersive Diffraction

One of the multiple capabilities of the new Joint Engineering, Environmental and Processing (JEEP) beamline I12 at Diamond Light Source is the set-up for polychromatic high-energy X-ray diffraction for the study of polycrystalline deformation and residual stresses. The results and interpretation of the first experiments carried out on JEEP are reported. Energy dispersive diffraction patterns from titanium alloy Ti-6Al-4V were collected using the new 23-cell ‘horseshoe’ detector and interpreted using Pawley refinement to determine the residual elastic strains at the macro- and meso-scale. It provides a clear demonstration of the tensile-compressive hardening asymmetry of the hexagonal close-packed grains oriented with the basal plane perpendicular to the loading direction.

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.

FORMATION OF THE "2223" SUPERCONDUCTING PHASE IN Bi4−xPbxSr3Ca3Cu4O16 SUPERCONDUCTORS

1990 ◽  
Vol 04 (10) ◽  
pp. 673-680
Author(s):  
I. M. TANG ◽  
K. EAIPRASERTSAK ◽  
R. CHITAREE
Keyword(s):  
High Temperature ◽  
Volume Fraction ◽  
Superconducting Phase ◽  
Temperature Decrease ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Temperature Component ◽  
Multiphase Systems ◽  
Temperature Component ◽  
Diffraction Patterns

Formation of the "2223" superconducting phase in Pb doped Bi 4 Sr 3 Ca 3 Cu 4 O 16 superconductor is studied. The X-ray diffraction patterns of the Bi 4−x Pb x Sr 3 Ca 3 Cu 4 O 16 (0.7 < x < 1.2) superconductors formed by various heat treatments indicate that they are all multiphase systems containing both the high T c and low T c superconductors, with the volume fraction of the "2223" phase increasing with increased Pb content. The high temperature component have extrapolated T c 's of around 105 K. The zero resistivity temperature decrease with lead content but are well above the reported T c (75 K) of the Pb free host superconductor.

scholarly journals In situ X-ray diffraction investigation of electric-field-induced switching in a hybrid improper ferroelectric

2021 ◽  
Vol 54 (2) ◽  
pp. 533-540
Author(s):  
Gabriel Clarke ◽  
Chris Ablitt ◽  
John Daniels ◽  
Stefano Checchia ◽  
Mark S. Senn
Keyword(s):  
Electric Field ◽  
Simulated Data ◽  
Functional Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Switching Mechanism ◽  
One Step ◽  
Diffraction Patterns ◽  
Ferroelectric Switching

Improper ferroelectric mechanisms are increasingly under investigation for their potential to expand the current catalogue of functional materials whilst promoting couplings between ferroelectricity and other technologically desirable properties such as ferromagnetism. This work presents the results of an in situ synchrotron X-ray diffraction experiment performed on samples of Ca2.15Sr0.85Ti2O7 in an effort to elucidate the mechanism of hybrid improper ferroelectric switching in this compound. By simultaneously applying an electric field and recording diffraction patterns, shifts in the intensity of superstructure peaks consistent with one of the switching mechanisms proposed by Nowadnick & Fennie [Phys. Rev. B, (2016), 94, 104105] are observed. While the experiment only achieves a partial response, comparison with simulated data demonstrates a preference for a one-step switching mechanism involving an unwinding of the octahedral rotation mode in the initial stages of switching. These results represent some of the first reported experimental diffraction-based evidence for a switching mechanism in an improper ferroelectric.

Residual Stresses in Aluminum-Mullite (α-Alumina) Composites*

1992 ◽  
Vol 36 ◽  
pp. 489-497
Author(s):  
Davor Balzar ◽  
Hassel Ledbetter
Keyword(s):  
Volume Fraction ◽  
Mechanical Equilibrium ◽  
X Ray Diffraction ◽  
Particle Volume ◽  
X Ray ◽  
The Matrix ◽  
Alumina Composites ◽  
Diffraction Patterns ◽  
Small Anisotropy ◽  
Three Phases

AbstractWe studied particle-reinforced 6061-aluminum-alloy composites with particle volume fractions ranging from 0 to 0.25. The mullite particles are approximately spherical and contain embedded α-alumina phase. We obtained lattice parameters of all three phases in the composites and starting materials by using Rietveld refinement of x-ray diffraction patterns. In all three phases stresses are tensile and approximately of the same magnitude, contradicting a requirement for mechanical equilibrium. Stresses increase with both increasing particle size and volume fraction. Measurements of extracted-from-composites particles showed no evidence of a possible chemical reaction at the matrix-particle interface. The matrix is [111] and [100] textured, but measurements of elastic constants reveal only small anisotropy. Thus, explanation of the mechanical-equilibrium violation remains uncertain.

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