In-Plane Rotated Crystal Structure in Continuous Growth of Bismuth Cuprate Superconducting Film

2008 ◽  
Vol 139 ◽  
pp. 53-58
Author(s):  
Satoru Kaneko ◽  
Kensuke Akiyama ◽  
Takeshi Ito ◽  
Yasuo Hirabayashi ◽  
Hiroshi Funakubo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Multilayered Structure ◽  
Superconducting Film ◽  
Reciprocal Space Mapping ◽  
Continuous Growth ◽  
X Ray ◽  
Unit Cells ◽  
Structural Modulation ◽  
Dominant Structure ◽  
Multilayer Strain

Bismuth cuprate superconductor has a unique structure called a structural modulation (supercell, SC) consisting of modulated several unit cells. Strain induced by multilayered structure increases the intensity of SC modulation, while an oxygen deficient sample shows expansion of SC size. In this study, as opposed to the multilayer strain, by preparing samples with thick film thicknesses the effect of strain on crystal structure was investigated including SC structure. Epitaxial growth was verified by x-ray diffraction, and the thicker film showed other epitaxial phase rotated 32° around the surface normal with respect to the initial epitaxial phase. The SC size estimated by x-ray reciprocal space mapping was double the size of the initial epitaxial phase. Interestingly, the initial epitaxial phase became a dominant structure after further deposition. In order to evaluate the different SC size and SC modulation, a new index related with an incline of the modulation vector was proposed.

Structural modulation on multilayered bismuth cuprate observed by x-ray reciprocal space mapping

2005 ◽  
Vol 97 (10) ◽  
pp. 103904 ◽  
Author(s):  
Satoru Kaneko ◽  
Kensuke Akiyama ◽  
Yoshitada Shimizu ◽  
Hiroyasu Yuasa ◽  
Yasuo Hirabayashi ◽  
...  
Keyword(s):  
Space Mapping ◽  
Reciprocal Space ◽  
Reciprocal Space Mapping ◽  
X Ray ◽  
Structural Modulation

Diffuse scattering and short-range order in uranium iodine phthalocyanine [U1−x Pc2]I2−y and the X-ray structure analysis of crystals with diffuse superstructure reflections

2003 ◽  
Vol 59 (3) ◽  
pp. 384-392 ◽  
Author(s):  
J. Krawczyk ◽  
A. Pietraszko ◽  
R. Kubiak ◽  
K. Łukaszewicz
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Diffuse Scattering ◽  
Short Range ◽  
Short Range Order ◽  
Crystal Structure Analysis ◽  
Range Order ◽  
Small Range ◽  
X Ray ◽  
Unit Cells

Crystals of uranium iodine phthalocyanine present an example of a disordered commensurate modulated structure of the intergrowth type. The short-range order of both uranium ions and iodine chains [I_3^-] n has been analysed by Reverse Monte Carlo (RMC) simulation of X-ray diffuse scattering. The diffraction pattern of uranium iodine phthalocyanine contains diffuse superstructure reflections. In the routine crystal structure analysis diffuse superstructure reflections may be either omitted or measured and classified along with other Bragg reflections. The crystal structure of uranium iodine phthalocyanine is an example of such ambiguity. The crystal structures of two specimens of [U1−x Pc2]I2−y with slightly different composition have been published in the literature with different space groups and unit cells. We have shown that the structure of both specimens differs only in the degree of short-range order and is isostructural with [YbPc2]I2. We have also shown that while the omission of diffuse reflections results in the average crystal structure, the treatment of these reflections as normal Bragg reflections is incorrect and produces the structure averaged over a limited small range.

Structural Modulation in Oxygen Deficient Epitaxial Bi2Sr2Ca1Cu2OXObserved by X-ray Reciprocal Space Mapping

2005 ◽  
Vol 44 (1A) ◽  
pp. 156-157 ◽  
Author(s):  
Satoru Kaneko ◽  
Kensuke Akiyama ◽  
Yoshitada Shimizu ◽  
Yasuo Hirabayashi ◽  
Keisuke Saito ◽  
...  
Keyword(s):  
Space Mapping ◽  
Reciprocal Space ◽  
Reciprocal Space Mapping ◽  
X Ray ◽  
Structural Modulation

Structural study in the oligomethylene dithiobenzoate series, nDBS, where n, the number of methylene groups, is odd

1992 ◽  
Vol 70 (3) ◽  
pp. 900-909 ◽  
Author(s):  
Claude Leblanc ◽  
François Brisse
Keyword(s):  
Crystal Structure ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cells ◽  
Methylene Groups ◽  
Unit Cell Dimensions ◽  
Centrosymmetric Dimers

Model compounds of the poly(oligomethylene thioterephthalates) have been synthesized and characterized by X-ray diffraction analyses. The pink n-methylenedithiobenzoates, obtained for n = 3, 5, 7, and 9, all have a low melting point of about 320–330 K. They all crystallize in the monoclinic system, space group P21/c. The a and b unit cell dimensions vary little while the c dimension increases monotonically as n changes from 3 to 9. The crystal structure of the four compounds were established from low-temperature X-ray intensities. Except for the lengthening of the methylenic sequence, the four molecules studied here are isostructural. One of the thiobenzoate groups of the molecules is coplanar with all the methylenic carbons, while the other thiobenzoate group is at 90° from the above plane of atoms. The methylenic sequence has the same conformation. It may be described by g+(t)n, where n is the number of methylene groups. Thus, the four compounds belong to a crystallographically homologous series. The molecules form centrosymmetric "dimers," which, in turn, are herring-bone packed in their respective unit cells. In each "dimmer" two aromatic rings are across from one another while being mutually perpendicular. On the basis of the above results, one proposes three potentially acceptable structures for the parent poly(oligomethylene thioterephthalates). Keywords: dithiobenzoate, methylene sequence, crystal structure, poly(oligomethylene thioterephthalate).

Crystal Structures of Modulated Martensitic Phases of FSM Heusler Alloys

2011 ◽  
Vol 684 ◽  
pp. 105-116 ◽  
Author(s):  
Lara Righi ◽  
Franca Albertini ◽  
Simone Fabbrici ◽  
Antonio Paoluzi
Keyword(s):  
Magnetic Field ◽  
Crystal Structure ◽  
Heusler Alloys ◽  
The Other ◽  
Basic Unit ◽  
Powder Diffraction Data ◽  
Unit Cells ◽  
Structural Modulation ◽  
Superspace Formalism ◽  
Ferromagnetic Shape Memory

Multifunctional ferromagnetic shape memory Heusler alloys are frequently characterized by structural modulation in martensitic phases. In particular, modulated martensitic phases, showing the higher magnetic field induced strain (MFIS) performance, are the most promising candidates for technological applications. Depending on the composition, as well as pressure and temperature conditions, this periodic structural distortion, consisting of shuffling of atomic layers along defined crystallographic directions, accompanies the martensitic transformation. Over the years, different Ni-Mn-Ga modulated martensitic structures have been observed and classified depending upon the periodicity of corresponding ideal nM superstructure (where n indicates the number of basic unit cells constituting the superlattices). On the other hand, it has been demonstrated that in most cases such structural modulation is incommensurate and the crystal structure has been fully determined by applying superspace formalism. The results, obtained by structure refinements on powder diffraction data, suggest a unified crystallographic description of the modulated martensitic structures, here presented, where every different “nM” periodicity can be straightforwardly represented.

Dehydroxylation of Fe3+ , Mg-rich dioctahedral micas: (I) structural transformation

Clay Minerals ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 491-504 ◽  
Author(s):  
F. Muller ◽  
V. A. Drits ◽  
A. Plançon ◽  
G. Besson
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Structural Models ◽  
Structural Transformations ◽  
X Ray ◽  
Plane Component ◽  
Unit Cells ◽  
Different Temperatures ◽  
Xrd Patterns ◽  
Octahedral Cations

AbstractCeladonite and glauconite samples heated at different temperatures were studied by X-ray and electron diffraction. For dioctahedral micas the in-plane component of the translation between layers (ccosβ/a), which is strongly dependent on the position of the vacant octahedral site, significantly decreases at temperatures greater than the temperature of maximum dehydroxylation. The simulation of XRD patterns from different structural models reveals the actual crystal structure of dehydroxylated samples as well as the dynamics of the structural transformations. In the nonheated state the samples consist of tv (trans-vacant) 2:1 layers. During dehydroxylation, cations migrate from cis- into trans-octahedra and have 5-fold coordination. In the averaged unit-cell the ‘residual’ anions formed after the dehydroxylation reaction occupy the former OH sites with probability equal to 0.5. The migration of octahedral cations is accompanied by the transformation of the C-centred layer unit-cells into primitive ones. In contrast to Fe, Al and Mg cations have a greater ability to migrate.

Structure determination of di-μ-hydroxo-bis[(2-(2-pyridyl)phenyl-κ2 N,C 1)palladium(II)] by X-ray powder diffractometry

2007 ◽  
Vol 63 (1) ◽  
pp. 75-80 ◽  
Author(s):  
J. Pérez ◽  
J. L. Serrano ◽  
J. M. Galiana ◽  
F. L. Cumbrera ◽  
A. L. Ortiz ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Search Algorithm ◽  
Parallel Tempering ◽  
X Ray Diffraction ◽  
Fourier Synthesis ◽  
X Ray ◽  
Planar Conformation ◽  
Unit Cells ◽  
Difference Fourier

The title compound was synthesized in the form of a powder, and was studied by elemental analysis, IR spectroscopy, thermogravimetry and mass spectroscopy. Its crystal structure was then determined by X-ray powder diffractometry, using X-ray diffraction data collected in the reflection Bragg–Brentano geometry. The methodology followed in the present study to resolve the crystal structure consisted of peak indexing, then the use of the Monte-Carlo/parallel tempering search algorithm, and finally Rietveld refinement coupled with difference-Fourier synthesis. We found that the crystals are composed of monoclinic unit cells, with 1.5 molecules in the asymmetric unit and therefore six molecules per unit cell. In addition, we concluded that the complexes adopt a planar conformation, forming trimers created by groups of parallel molecules.

Structural modulation in bismuth cuprate superconductor observed by X-ray reciprocal space mapping

2006 ◽  
Vol 287 (2) ◽  
pp. 483-485 ◽  
Author(s):  
Satoru Kaneko ◽  
Kensuke Akiyama ◽  
Yoshitada Shimizu ◽  
Yasuo Hirabayashi ◽  
Seishiro Ohya ◽  
...  
Keyword(s):  
Cuprate Superconductor ◽  
Space Mapping ◽  
Reciprocal Space ◽  
Reciprocal Space Mapping ◽  
X Ray ◽  
Structural Modulation

Diffuse X-ray scattering and reverse Monte Carlo simulation of the short-range order in ytterbium iodine phthalocyanine [YbPc2]I2

2002 ◽  
Vol 58 (4) ◽  
pp. 622-626 ◽  
Author(s):  
J. Krawczyk ◽  
A. Pietraszko ◽  
K. Łukaszewicz
Keyword(s):  
Crystal Structure ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
X Ray ◽  
X Ray Scattering ◽  
Unit Cells ◽  
Reverse Monte Carlo Simulation ◽  
Complicated Pattern ◽  
Ray Scattering

Iodine-doped ytterbium phthalocyanine, C64H32N16YbI2, [YbPc2]I2 (YPI), presents an example of a disordered modulated crystal structure of the intergrowth type. The short-range order in YPI has been studied at ambienttemperature by the diffuse X-ray scattering technique. Both Yb and I atoms are disordered. In a unit cell of the average structure, the Yb atoms occupy two positions, \textstyle {{1} \over {2}}, \textstyle {{1} \over {2}}, \textstyle {{1} \over {4}} or \textstyle {{1} \over {2}}, \textstyle {{1} \over {2}}, \textstyle {{3} \over {4}}, with occupancy 0.5. In the neighbouring unit cells in the (001) plane there is, however, a strong tendency towards an alternating distribution of ytterbium in positions shifted by Δz = \textstyle {{1} \over {2}}. The crystal structure of YPI consists of one-dimensional columnar stacks of [{\rm YbPc} _{2} ^{2/3+}] n and of linear iodine chains [{\rm I} _{3} ^{-}] n . The modulation is commensurate since the period c I of iodine chains [{\rm I} _{3} ^{-}] n in the [001] direction is equal to one-half of the period c of the [{\rm YbPc} _{2} ^{2/3+}] n stacks. In the crystal structure, each stack of [{\rm YbPc} _{2} ^{2/3+}] n may occur in two settings shifted by c/2 and each iodine chain in three settings shifted along [001] by one-third of the period c I. The short-range order of iodine chains distributed over three settings results in a complicated pattern. Iodine chains of the same setting tend to form ribbons perpendicular to 〈100〉 and running along [001].

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