Synthesis of (Bi2Te3)x(TiTe2)y and (Bi2Te3)x(TiTe2)3 Superlattices

2005 ◽  
Vol 886 ◽  
Author(s):  
Mary Smeller ◽  
Fred R. Harris ◽  
David C. Johnson
Keyword(s):  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Characteristic Structure ◽  
X Ray ◽  
Modulated Elemental Reactants ◽  
Annealing Conditions ◽  
Linear Behavior ◽  
Deposition Parameters ◽  
Elemental Reactants ◽  
Diffraction Patterns

ABSTRACTThe synthesis of (Bi2Te3)x(TiTe2)x and (Bi2Te3)x(TiTe2)3 superlattices using modulated elemental reactants was successfully accomplished. This required the calibration of the deposition parameters to achieve both the desired atomic compositions of the constituent layers and the deposition of the absolute amounts of each of the components to yield the title compounds. Proper annealing conditions were determined from an investigation of the x-ray diffraction patterns of a superlattice sample as a function of annealing temperature. The change in lattice parameters as a function of x showed the expected linear behavior with slopes consistent with values expected from the published lattice parameters of the binary components. Rietveld refinement showed that the characteristic structure of the binary components is maintained in the superlattices studied.

X-ray powder diffraction studies of (BaxSr1−x)2Co2Fe12O22 and (BaxSr1−x)Co2Fe16O27

2015 ◽  
Vol 30 (2) ◽  
pp. 139-148 ◽  
Author(s):  
W. Wong-Ng ◽  
G. Liu ◽  
Y. Yan ◽  
K. R. Talley ◽  
J. A. Kaduk
Keyword(s):  
Seebeck Coefficient ◽  
Powder Diffraction ◽  
Lattice Parameters ◽  
Hexagonal Ferrite ◽  
Layered Compounds ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
Space Group ◽  
X Ray ◽  
Diffraction Patterns

X-ray structural characterization and X-ray reference powder patterns have been determined for two series of iron- and cobalt-containing layered compounds (BaxSr1−x)2Co2Fe12O22 (x = 0.2, 0.4, 0.6, 0.8) and (BaxSr1−x)Co2Fe16O27 (x = 0.2, 0.4, 0.6, 0.8). The (BaxSr1−x)2Co2Fe12O22 series of compounds crystallized in the space group R$\bar 3$m (No. 166), with Z = 3. The structure is essentially that of the Y-type hexagonal ferrite, BaM2+Fe63+O11. The lattice parameters range from a = 5.859 15(8) to 5.843 72(8) Å, and c = 43.4975(9) to 43.3516(9) Å for x = 0.2 to 0.8, respectively. The (BaxSr1−x)Co2Fe16O27 series (W-type hexagonal ferrite) crystallized in the space group P63/mmc (No. 194) and Z = 2. The lattice parameters range from a = 5.902 05(12) to 5.8979(2) Å and c = 32.9002(10) to 32.8110(13) Å for x = 0.2 to 0.8. Results of measurements of the Seebeck coefficient and resistivity of these two sets of samples indicated that they are insulators. Powder X-ray diffraction patterns of these two series of compounds have been submitted to be included in the Powder Diffraction File.

Synthesis of New Thermoelectrics Using Modulated Elemental Reactants

1997 ◽  
Vol 478 ◽  
Author(s):  
Marc D. Hornbostel ◽  
Heike Sellinschegg ◽  
David C. Johnson
Keyword(s):  
Crystal Structure ◽  
X Ray Diffraction ◽  
Systematic Screening ◽  
X Ray ◽  
Low Temperature Annealing ◽  
Modulated Elemental Reactants ◽  
Ternary Metal ◽  
Elemental Reactants ◽  
Binary Compounds ◽  
New Compounds

AbstractA series of new, metastable ternary crystalline compounds with the skutterudite crystal structure have been synthesized using modulated elemental reactants. The initial reactants are made up of multiple repeats of a ˜25Å thick unit containing elemental layers of the desired ternary metal, iron and antimony. Low temperature annealing (150°C) results in interdiffusion of the elemental layers to form amorphous reaction intermediates. Annealing these intermediates at temperatures between 200°C and 250°C results in exothermic crystallization of the desired skutterudite crystal structure. Most of the new compounds prepared are only kinetically stable, decomposing exothermically to form thermodynamically more stable mixtures of binary compounds and elements. Low angle x-ray diffraction studies show that the resulting films are exceedingly smooth. These films have an ideal geometry for measuring properties of importance for thermoelectric devices—the Seebeck coefficient and the electrical conductivity. Thermal conductivity can be measured using a modification of the 3ω technique of Cahill. Samples can be produced rapidly, allowing for systematic screening and subsequent optimization as a function of composition and doping levels.

The nanodiffraction problem

2018 ◽  
Vol 51 (4) ◽  
pp. 1102-1115 ◽  
Author(s):  
Shangmin Xiong ◽  
Hande Öztürk ◽  
Seung-Yub Lee ◽  
Patricia M. Mooney ◽  
Ismail Cevdet Noyan
Keyword(s):  
Lattice Parameters ◽  
Nanocrystalline Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Size Dependent ◽  
Inverse Power Law ◽  
Rigorous Study ◽  
Diffraction Patterns ◽  
20 Nm ◽  
True Values

The results of a systematic rigorous study on the accuracy of lattice parameters computed from X-ray diffraction patterns of ideally perfect nanocrystalline powder and thin-film samples are presented. It is shown that, if the dimensions of such samples are below 20 nm, the lattice parameters obtained from diffraction analysis will deviate from their true values. The relative deviation depends on the relevant size parameter through an inverse power law and, for particular reflections, depends on the angular peak positions. This size-dependent error, Δa/a, is larger than the precision of typical X-ray diffraction measurements for ∼20 nm-thick diffracting domains, and it can be several orders of magnitude larger for particles smaller than 5 nm.

Crystal structures and reference X-ray powder diffraction patterns of Sr4−xCaxPb2O8 (x=1,2,3)

1998 ◽  
Vol 13 (4) ◽  
pp. 232-240 ◽  
Author(s):  
W. Wong-Ng ◽  
J. A. Kaduk ◽  
W. Greenwood
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Alkaline Earth ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
X Ray ◽  
Diffraction Patterns

The crystal structure of the solid solution alkaline earth plumbate phase Sr4−xCaxPb2O8 was investigated using the X-ray Rietveld technique for x=1, 2, and 3. The lattice parameters a, b, c, and V were found to decrease linearly as the Sr at site 4h was replaced by Ca. The structure features chains of edge-sharing PbO6 octahedra, linked by seven-coordinated (Ca/Sr)–O monocapped trigonal prisms. The structure is similar to that of Pb3O4, which can be reformulated as Pb2IIPbIVO4. X-ray diffraction patterns for the solid solution members SrCa3Pb2O8, Sr2Ca2Pb2O8, and Sr3CaPb2O8 were prepared for inclusion in the Powder Diffraction File.

Zur Kenntnis von Hydridhalogeniden MHX der Seltenen Erden Eu, Yb und Sm (X = Cl, Br, I) / A Study on Hydride Halide Compounds MHX of the Rare Earths Eu,Yb, and Sm (X = Cl,Br,I)

1982 ◽  
Vol 37 (5) ◽  
pp. 574-578 ◽  
Author(s):  
H. P. Beck ◽  
A. Limmer
Keyword(s):  
Solid State ◽  
Crystal Chemistry ◽  
Rare Earths ◽  
Alkaline Earth ◽  
Lattice Parameters ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns

New hydride halide compounds MHX (M = Eu, Yb, Sm; X = Cl, Br, I) of divalent rare earths have been prepared by solid-state reactions. Lattice parameters and X-ray diffraction patterns are presented for these compounds. All compounds are isostructural with tetragonal PbFCl. Refined lattice parameters of alkaline earth hydride halides are given. The crystal chemistry of MHX and MFX is compared and the geometric variations in the structure of these compounds are interpreted on the basis of changes in covalency

Formation of Superconducting La2−xSrxCaCu2O6−δ Ceramic with Application of O2-HIP Technique

1991 ◽  
Vol 251 ◽  
Author(s):  
Kiyoshi Oshima ◽  
Yuichi Watanabe ◽  
Masasuke Takata ◽  
Kozo Ishizaki
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Strong Correlation ◽  
Hot Isostatic Pressing ◽  
Lattice Parameters ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isostatic Pressing ◽  
Diffraction Patterns

ABSTRACTSuperconducting La2−xSrxCaCu2O6−δ ceramics (x=0−0.6) were prepared with application of the oxygen-hot-isostatic pressing (O2-HIP) technique. The Tc of various samples was found to depend on both the Sr content and the applied oxygen partial pressure in the HIP treatment. The maximum Tc onset of 50K was observed for samples of the composition x=0.3 and 0.4 HIPped at 1050°C under 60atm oxygen partial pressure, and x=0.1 and 0.2 HIPped at 1050°C under 400atm oxygen partial pressure, respectively. From the analysis of x-ray diffraction patterns for superconducting substances, it was found that there existed a strong correlation between superconducting properties and the lattice parameters.

A study of the non-stoicheiometric, lime-type phase occurring in the system Ca-O-N

1966 ◽  
Vol 19 (5) ◽  
pp. 725 ◽  
Author(s):  
DJM Bevan ◽  
FJ Lincoln ◽  
FD Richardson
Keyword(s):  
Nitrogen Content ◽  
Linear Function ◽  
Calcium Oxide ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Type Phase ◽  
Diffraction Patterns ◽  
Oxynitride Phase

A brown, strongly reducing, non-stoicheiometric calcium oxynitride phase has been prepared by heating calcium oxide pellets at about 1100� in an atmosphere of calcium vapour and nitrogen derived from heated calcium nitride. The compositions studied ranged between CaNo.oo4O0.99(2) and CaNo.070O0.82(5). X-ray diffraction patterns were of a face-centred cubic lime-type phase with lattice parameters expanded with respect to that of pure lime; the expansion was a linear function of the nitrogen content. The possible nature of this non-stoicheiometric solid is discussed.

scholarly journals Common architectures in cyanobacteria Prochlorococcus cells visualized by X-ray diffraction imaging using X-ray free electron laser

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amane Kobayashi ◽  
Yuki Takayama ◽  
Takeshi Hirakawa ◽  
Koji Okajima ◽  
Mao Oide ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Single Cells ◽  
Three Dimensional ◽  
Biological Functions ◽  
X Ray Diffraction ◽  
Characteristic Structure ◽  
X Ray ◽  
Diffraction Imaging ◽  
Diffraction Patterns

AbstractVisualization of intracellular structures and their spatial organization inside cells without any modification is essential to understand the mechanisms underlying the biological functions of cells. Here, we investigated the intracellular structure of cyanobacteria Prochlorococcus in the interphase by X-ray diffraction imaging using X-ray free-electron laser. A number of diffraction patterns from single cells smaller than 1 µm in size were collected with high signal-to-noise ratio with a resolution of up to 30 nm. From diffraction patterns, a set of electron density maps projected along the direction of the incident X-ray were retrieved with high reliability. The most characteristic structure found to be common among the cells was a C-shaped arrangement of 100-nm sized high-density spots, which surrounded a low-density area of 100 nm. Furthermore, a three-dimensional map reconstructed from the projection maps of individual cells was non-uniform, indicating the presence of common structures among cyanobacteria cells in the interphase. By referring to the fluorescent images for distributions of thylakoid membranes, nucleoids, and carboxysomes, we inferred and represented their spatial arrangements in the three-dimensional map. The arrangement allowed us to discuss the relevance of the intracellular organization to the biological functions of cyanobacteria.

Aspects of Order during the Deformation of Nylon Fibers

1969 ◽  
Vol 39 (7) ◽  
pp. 662-666 ◽  
Author(s):  
R. N. Kelley ◽  
W. O. Statton
Keyword(s):  
Random Copolymer ◽  
Kinetic Mechanism ◽  
Original Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Conditions ◽  
Local Ordering ◽  
Local Lattice ◽  
Diffraction Patterns ◽  
Thermodynamic Mechanism

Different structure parameters can be measured in wide- and small-angle x-ray diffraction patterns of fibers which describe order. A brief study of these parameters is given for fibers of 66 nylon and for fibers of a random copolymer of 66/6 (90/10) which had been produced by a variety of drawing and annealing conditions. No direct correlation of the order parameters is found, suggesting that they vary independently. Part of the long-period intensity is found to be created by heating and is not a remnant of the disruption of the original structure. It is proposed that the gross ordering process is dominated by a thermodynamic mechanism. On the other hand, the local lattice ordering is sensitive to both tension and temperature conditions, and it is proposed that local ordering is dominated by a kinetic mechanism

Preparation of [(Bi2Te3)x(HfTe2)]y Superlattices

2005 ◽  
Vol 886 ◽  
Author(s):  
Benjamin Allen Schmid ◽  
Fred R Harris ◽  
David C Johnson
Keyword(s):  
Annealing Temperature ◽  
Amorphous State ◽  
X Ray Diffraction ◽  
X Ray ◽  
Modulated Elemental Reactants ◽  
Elemental Reactants

ABSTRACTThe synthesis of a number of (Bi2Te3)x(HfTe2)y superlattices was accomplished using the modulated elemental reactants (MER) method. The samples were characterized using X-ray reflectivity and X-ray diffraction in the as deposited (amorphous) state and as a function of annealing temperature and time.

Sign in / Sign up

Export Citation Format

Share Document