X-ray powder diffraction analysis of the incommensurate modulated structure of Bi2Sr2CaCu2O8

1994 ◽  
Vol 9 (1) ◽  
pp. 28-37 ◽  
Author(s):  
D. P. Matheis ◽  
R. L. Snyder
Keyword(s):  
Powder Diffraction ◽  
Structural Parameters ◽  
Lattice Parameter ◽  
Processing Conditions ◽  
Modulated Structure ◽  
X Ray ◽  
Modulated Structures ◽  
Sample Composition ◽  
Modulation Model ◽  
Modulation Vector

X-ray powder diffraction is a convenient tool for monitoring changes in structural parameters due to modifications in sample composition and processing conditions. Due to the complexity of incommensurate modulated structures powder diffraction techniques have not been commonly applied. Programs ALSQ and QRIET have been produced to perform lattice parameter and structure refinements on incommensurate modulated materials with a displacive modulation model. In applying these programs to the Bi2Sr2CaCu2O8 superconductor which has this type of structure, it is shown that a decrease in the lattice parameters and an increase in the modulation vector occurs as the Ca content of the Bi-2212 phase, controlled by the use of the glass ceramic process, increases.

Refinement of modulated structures against X-ray powder diffraction data withJANA2000

2001 ◽  
Vol 34 (3) ◽  
pp. 398-404 ◽  
Author(s):  
M. Dušek ◽  
V. Petříček ◽  
M. Wunschel ◽  
R. E. Dinnebier ◽  
S. van Smaalen
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Structural Parameters ◽  
Icosahedral Symmetry ◽  
Temperature Structure ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Modulated Structures ◽  
Single Crystal Study ◽  
Composite Crystals

JANAis a computer program for the refinement and analysis of periodic and aperiodic (incommensurately modulated structures and composite crystals) crystal structures. Here a new module is introduced that allows Rietveld refinements against powder diffraction data. It is shown thatJANA2000 provides a state-of-the-art description of the peak profiles. A re-analysis of the low-temperature structure of (CO)xC60showed that the application of icosahedral symmetry restrictions to the C60molecule leads to a better description of the electron density and to a corrected position of the CO molecule as compared with a rigid-body refinement. The incommensurately modulated structure of NbTe4has been successfully refined against X-ray powder diffraction data. The structural parameters are equal to, but less accurate, than the parameters obtained from a single-crystal study.

Synchrotron X-ray studies of metal-organic framework M2(2,5-dihydroxyterephthalate), M = (Mn, Co, Ni, Zn) (MOF74)

2012 ◽  
Vol 27 (4) ◽  
pp. 256-262 ◽  
Author(s):  
W. Wong-Ng ◽  
J. A. Kaduk ◽  
H. Wu ◽  
M. Suchomel
Keyword(s):  
Powder Diffraction ◽  
Metal Organic Framework ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Lattice Parameter ◽  
X Ray ◽  
Metal Organic ◽  
Sorbent Materials ◽  
Diffraction Patterns ◽  
Unsaturated Metal Sites

M2(dhtp)·nH2O (M = Mn, Co, Ni, Zn; dhtp = 2,5-dihydroxyterephthalate), known as MOF74, is a family of excellent sorbent materials for CO2 that contains coordinatively unsaturated metal sites and a honeycomb-like structure featuring a broad one-dimensional channel. This paper describes the structural feature and provides reference X-ray powder diffraction patterns of these four isostructural compounds. The structures were determined using synchrotron diffraction data obtained at beam line 11-BM at the Advanced Photon Source (APS) in the Argonne National Laboratory. The samples were confirmed to be hexagonal R 3 (No. 148). From M = Mn, Co, Ni, to Zn, the lattice parameter a of MOF74 ranges from 26.131 73(4) Å to 26.5738(2) Å, c from 6.651 97(5) to 6.808 83(8) Å, and V ranges from 3948.08 Å3 to 4163.99 Å3, respectively. The four reference X-ray powder diffraction patterns have been submitted for inclusion in the Powder Diffraction File (PDF).

Synthesis and characterisation of transition metal substituted barium hollandite ceramics

2006 ◽  
Vol 932 ◽  
Author(s):  
Neil C. Hyatt ◽  
Martin C. Stennett ◽  
Steven G. Fiddy ◽  
Jayne S. Wellings ◽  
Sian S. Dutton ◽  
...  
Keyword(s):  
Transition Metal ◽  
Oxidation State ◽  
Powder Diffraction ◽  
Single Phase ◽  
Maximum Density ◽  
Processing Conditions ◽  
Metal Oxidation ◽  
Exafs Data ◽  
X Ray ◽  
Oxygen Atoms

ABSTRACTA range of transition metal bearing hollandite phases, formulated Ba1.2B1.2Ti6.8O16 (B2+ = Mg, Co, Ni, Zn, Mn) and Ba1.2B2.4Ti5.6O16 (B3+ = Al, Cr, Fe) were prepared using an alkoxide - nitrate route. X-ray powder diffraction demonstrated the synthesis of single phase materials for all compositions except B = Mn. The processing conditions required to produce > 95 % dense ceramics were determined for all compositions, except B = Mg for which the maximum density obtained was > 93 %. Analysis of transition metal K-edge XANES data confirmed the presence of the targeted transition metal oxidation state for all compositions except B = Mn, where the overall oxidation state was found to be Mn3+. The K-edge EXAFS data of Ba1.2B1.2Ti6.8O16 (B = Ni and Co) were successfully analysed using a crystallographic model of the hollandite structure, with six oxygen atoms present in the first co-ordination shell at a distance of ca. 2.02Å. Analysis of Fe K-edge EXAFS data of Ba1.2B2.4Ti5.4O16 revealed a reduced co-ordination shell of five oxygens at ca. 1.99Å.

Rietveld Refinement of the BaTiO3 from X-Ray Powder Diffraction

2009 ◽  
Vol 79-82 ◽  
pp. 593-596
Author(s):  
Feng Sun ◽  
Yan Sheng Yin
Keyword(s):  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Structural Parameters ◽  
Ferroelectric Ceramic ◽  
Powder Diffraction Data ◽  
Ceramic Powders ◽  
Space Group ◽  
X Ray

The ferroelectric ceramic BaTiO3 was synthesized at 1000 °C for 5 h. The structure of the system under study was refined on the basis of X-ray powder diffraction data using the Rietveld method. The system crystallizes in the space group P4mm（99）. The refinement of instrumental and structural parameters led to reliable values for the Rp, Rwp and Rexp.We use the TOPAS software of Bruker AXS to refine this ceramic powders and show its conformation

SIZE-INDUCED EFFECTS IN NANOSTRUCTURED NiFe2O4

2010 ◽  
Vol 24 (30) ◽  
pp. 5973-5985
Author(s):  
M. GUNES ◽  
H. GENCER ◽  
T. IZGI ◽  
V. S. KOLAT ◽  
S. ATALAY
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Structural Parameters ◽  
Hydrothermal Process ◽  
Lattice Parameter ◽  
Effect Of Temperature ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

NiFe 2 O 4 nanoparticles were successfully prepared by a hydrothermal process, and the effect of temperature on them was studied. The particles were annealed at various temperatures ranging from 413 to 1473 K. Studies were carried out using powder X-ray diffraction, scanning electron microscopy, infrared spectroscopy, differential thermal analysis, thermogravimetric analysis and a vibrating sample magnetometer. The annealing temperature had a significant effect on the magnetic and structural parameters, such as the crystallite size, lattice parameter, magnetization and coercivity.

X-ray powder diffraction data of CoSi

1997 ◽  
Vol 12 (4) ◽  
pp. 252-254 ◽  
Author(s):  
G. Ghosh ◽  
G. V. Narasimha Rao ◽  
V. S. Sastry ◽  
A. Bharathi ◽  
Y. Hariharan ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Melting Process ◽  
Lattice Parameter ◽  
Powder Diffraction Data ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
Arc Melting ◽  
Cubic Structure

X-ray powder diffraction data of CoSi are reported. The sample was prepared by an arc melting process and has a cubic structure (space group P213, space group No. 198) with lattice parameter a=4.4427 Å, Dx=6.591 gcm−3, Z=4, and I/Ic=1.03.

An Approach to the Solid Solution Problem Using a Computerized Identification Technique

1969 ◽  
Vol 13 ◽  
pp. 539-549
Author(s):  
Gerald G. Johnson ◽  
Frank L. Chan
Keyword(s):  
Solid Solution ◽  
Powder Diffraction ◽  
Lattice Parameter ◽  
Powder Diffraction File ◽  
X Ray ◽  
Complete Solid Solution ◽  
Vegard’S Law ◽  
Identification Technique ◽  
Approximate Composition ◽  
End Members

Since for most real systems, solid solution effects influence the position and intensity of the x-ray powder diffraction pattern, it is desirable and necessary to have an automatic system which will identify standard reference phases regardless of the amount of solid solution. Using the system CdS-ZnS, where the lattice parameter a0 changes from 4.136 to 3.820Å, with complete solid solution over the entire range of composition, an illustrative study was made. This work presents the results obtained from a computer analysis of the powder pattern obtained. It has been found that if the starting chemistry is known and the end members of the series are in the ASTM Powder Diffraction File, that the solid solution can be identified. Once the phases present are identified, a plot following Vegard's law yields the approximate composition of the sample under consideration. These two methods of compositional determination agree quite well. Examples of the computer system and description of the program input and output with interpretation of the results will be discussed.

X-ray powder diffraction data for ErH2−xDx

2008 ◽  
Vol 23 (3) ◽  
pp. 259-264 ◽  
Author(s):  
Mark A. Rodriguez ◽  
Robert M. Ferrizz ◽  
Clark S. Snow ◽  
James F. Browning
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Room Temperature ◽  
Lattice Parameter ◽  
Powder Diffraction Data ◽  
Mole Percent ◽  
X Ray ◽  
Cubic Lattice ◽  
Fluorite Type ◽  
Hydrogen Deuterium

X-ray powder diffraction data for ErH2−xDx formed by hydrogen (i.e., protium)–deuterium loading of Er metal are reported. Lattice parameters for the varying hydrogen–deuterium compositions followed Vergard’s law behavior. The cubic lattice parameter at room temperature for ErH2−xDx obeys a linear relationship according to the formula a=5.1287−1.1120×10−4⋅x, where a is the lattice parameter of the fluorite-type structure and x is the mole percent of deuterium. Microstrain measurements suggest a possible ordering of hydrogen and deuterium in the composition ErH1D1.

The use of lattice-parameter changes to trace the kinetics of phase transformations powder-diffraction analysis of disorder-order transformations in Ni1+δSn

2007 ◽  
Vol 222 (3-4) ◽  
Author(s):  
Andreas Leineweber ◽  
Eric J. Mittemeijer
Keyword(s):  
Phase Transformation ◽  
Diffraction Analysis ◽  
Phase Transformations ◽  
Powder Diffraction ◽  
Lattice Parameter ◽  
X Ray ◽  
Kinetics Of

The measurement of lattice-parameter changes by X-ray powder diffraction as a function of the progress of a phase transformation (

X-ray powder diffraction data for rhombohedral AlPt

2006 ◽  
Vol 21 (4) ◽  
pp. 318-319
Author(s):  
Mark A. Rodriguez ◽  
David P. Adams
Keyword(s):  
Thin Film ◽  
High Temperature ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Lattice Parameter ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Space Group ◽  
X Ray ◽  
High Temperature Reactions

X-ray powder diffraction data for a rhombohedral AlPt phase formed by self-propagating, high-temperature reactions of Al∕Pt bi-layer films are reported. Multilayer Al∕Pt thin film samples, reacted in air or vacuum, transformed into rhombohedral AlPt with space group R-3(148). Indexing and lattice parameter refinement of AlPt powders (generated from thin-film samples) yielded trigonal/hexagonal unit-cell lattice parameters of a=15.623(6) Å and c=5.305(2) Å, Z=39, and V=1121.5 Å3.

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