Strukturverfeinerung des Kompositkristalls im mehrdimensionalen Raum

Kato, K.

doi:10.1107/s0108768189008931

Cited by 70 publications

(13 citation statements)

References 8 publications

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“…The statistical value of AIC ͑akaike information criterion͒ was 2702. 33 In Table I, several Fourier coefficients of the modulation function are fixed at 0 by considering the site symmetry of each atom in the average substructures. The thermal parameters are presented by U eq.…”

Section: ͑3͒mentioning

confidence: 99%

Structural modulation, hole distribution, and hole-ordered structure of the incommensurate composite crystal(Sr2Cu2
Gotoh
¹
,
Yamaguchi
²
,
Takahashi
³

et al. 2003
Phys. Rev. B
28
2
24
0
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Modulated structure of incommensurate composite crystal (Sr 2 Cu 2 O 3 ) 0.70 CuO 2 , ''Sr 14 Cu 24 O 41 ,'' has been investigated by single-crystal x-ray-diffraction method using centrosymmetric (3ϩ1)-dimensional superspace group. In (Sr 2 Cu 2 O 3 ) 0.70 CuO 2 , displacive modulation of O atom in the CuO 2 chain is fairly large. Considering the modulation of bond angles, it has been found that the Cu-O bond in the CuO 2 chain is tilting toward the Cu 2 O 3 ladder in order that the O atom in the chain plays as apical oxygen for the CuO 4 square in the ladder. The bond-valence sum ͑BVS͒ method has been applied to investigate the hole distribution in the modulated structure of (Sr 2 Cu 2 O 3 ) 0.70 CuO 2 . It is indicated that the valence of Cu atom in the Cu 2 O 3 ladder is ϩ2.04, where about 0.03 holes are certainly transferred from the CuO 2 chain through the modulated O atom in the CuO 2 . The BVS calculation has demonstrated that almost all of the holes are prepared in the CuO 2 chain by the large modulation of the Cu-O bond. Cu atoms in the modulated CuO 2 chain have been proved to form hole-ordered structure with next-nearest-neighbor Cu 2ϩ ions separated by Cu 3ϩ ion on the Zhang-Rice singlet site. The periodicity of the hole-ordered structure is five times of the average CuO 2 lattice along the crystallographic c axis, which is compatible with the spin-dimerized state at low temperature. The new model of the two-dimensional hole-ordered structure in the CuO 2 plane has been obtained by the BVS calculation. Furthermore, the two-dimensional configuration of the spin dimers has been successfully derived from the holeordered structure in the CuO 2 plane. It has been concluded that the valences of Cu atoms both in the Cu 2 O 3 ladder and in the CuO 2 chain are well controlled by the modulated O atom in the CuO 2 chain.

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Section: ͑3͒mentioning

confidence: 99%

Structural modulation, hole distribution, and hole-ordered structure of the incommensurate composite crystal(Sr2Cu2
Gotoh
¹
,
Yamaguchi
²
,
Takahashi
³

et al. 2003
Phys. Rev. B
28
2
24
0
View full text Add to dashboard Cite

show abstract

“…This type of structures has been studied by single-crystal X-ray diffraction [13] and by electron microscopy [14][15][16]. Due to the mutually incommensurate character of the two composing sublattices, apart from the reflections of each subsystem, satellite reflections appear in the diffraction pattern.…”

Section: Introductionmentioning

confidence: 99%

“…A supercell approach, based on the closeness of the misfit parameter to a rational number has also been used. However, the most accurate method for structure refinement from diffraction data has been shown to be the higher dimensional superspace approach [13,[17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Structure and microstructure of the high pressure synthesised misfit layer compound [Sr2O2][CrO2]1.85

Castillo‐Martínez¹,

Schönleber²,

Smaalen³

et al. 2008

Journal of Solid State Chemistry

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a b s t r a c tThe strontium chromium oxide [Sr 2 O 2 ][CrO 2 ] 1.85 misfit layer compound has been synthesised at highpressure and high-temperature conditions. Electron diffraction patterns and high-resolution transmission electron microscopy images along [001] show the misfit character of the different layers composing the structure with a supercell along the incommensurate parameter bE7b 1 E13b 2 . The modulated crystal structure has been refined within the superspace formalism against single-crystal X-ray diffraction data, employing the (3+1)-dimensional superspace group C 0 nmb(0s 2 0)0 0 s. The compound has a composite structure with lattice parameters a 1 ¼ 5.182(1) Å , b 1 ¼ 5.411(1) Å , c 1 ¼ 18.194(3) Å for the first, SrO, subsystem and the same a and c, but with b 2 ¼ 2.925(1) Å for the second, CrO 2 , subsystem. The layer stacking is similar to that of orthorhombic PbS(TiS 2 ) 1.18 , but with a much stronger intersubsytem bonding in the case of the oxide. The intersubsystem lattice mismatch is mainly handled by displacement modulations of the Sr atoms, correlated with modulations of the valence, the coordination and the anisotropic displacement parameters.

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“…O cc ;U eq 0.5,0.5,0 0.5;0.045(2) 0.5,0.5,0 0.5;0.0330(15) common (hk00), ladder (hkl0), chain (hk0m) and satellite (hklm) Bragg peaks (from top to bottom), respectively.FIG. 3.…”

mentioning

confidence: 99%

Structural evolution of one-dimensional spin-ladder compounds Sr14−xCaxCu24
Deng
¹
,
Pomjakushin
²
,
Petřı́ček
³

et al. 2011
Phys. Rev. B
23
2
37
1
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Incommensurate crystal structures of spin ladder series Sr 14-x Ca x Cu 24 O 41 (x=3, 7, 11, 12.2) were characterized by powder neutron scattering method and refined using the superspace group Xmmm(00γ)ss0 (equivalent to superspace group Fmmm(0,0,1+γ)ss0); X stands for non-standard centering (0,0,0,0), (0,½,½,½), (½,½,0,0), (½,0,½,½)) with a modulated structure model. The Ca doping effects on the lattice parameters, atomic displacement, Cu-O distances, Cu-O bond angles and Cu bond valence sum were characterized. The refined results show that the CuO 4 planar units in both chain and ladder sublattices become closer to square shape with an increase of Ca doping.The Cu bond valence sum calculation provided new evidence for the charge transfer from the chains to ladders (approximately 0.16 holes per Cu from x=0 to 12.2). The charge transfer was attributed to two different mechanisms: (a) the Cu-O bond distance shrinkage on the ladder; (b) increase of the interaction between two sublattices, resulting in Cu-O bonding between the chains

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Strukturverfeinerung des Kompositkristalls im mehrdimensionalen Raum

Abstract: The superspace-group approach formulated for composite crystals by Janner & Janssen [Acta Cryst.

Cited by 70 publications

References 8 publications

Structural modulation, hole distribution, and hole-ordered structure of the incommensurate composite crystal(Sr2Cu2
Gotoh
¹
,
Yamaguchi
²
,
Takahashi
³

et al. 2003
Phys. Rev. B
28
2
24
0
View full text Add to dashboard Cite

Structural modulation, hole distribution, and hole-ordered structure of the incommensurate composite crystal(Sr2Cu2
Gotoh
¹
,
Yamaguchi
²
,
Takahashi
³

et al. 2003
Phys. Rev. B
28
2
24
0
View full text Add to dashboard Cite

Structure and microstructure of the high pressure synthesised misfit layer compound [Sr2O2][CrO2]1.85

Structural evolution of one-dimensional spin-ladder compounds Sr14−xCaxCu24
Deng
¹
,
Pomjakushin
²
,
Petřı́ček
³

et al. 2011
Phys. Rev. B
23
2
37
1
View full text Add to dashboard Cite

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Strukturverfeinerung des Kompositkristalls im mehrdimensionalen Raum

Abstract: The superspace-group approach formulated for composite crystals by Janner & Janssen [Acta Cryst.

Cited by 70 publications

References 8 publications

Structural modulation, hole distribution, and hole-ordered structure of the incommensurate composite crystal(Sr2Cu2Gotoh1, Yamaguchi2, Takahashi3 et al. 2003Phys. Rev. B282240View full textAdd to dashboardCite

Structural modulation, hole distribution, and hole-ordered structure of the incommensurate composite crystal(Sr2Cu2Gotoh1, Yamaguchi2, Takahashi3 et al. 2003Phys. Rev. B282240View full textAdd to dashboardCite

Structure and microstructure of the high pressure synthesised misfit layer compound [Sr2O2][CrO2]1.85

Structural evolution of one-dimensional spin-ladder compounds Sr14−xCaxCu24Deng1, Pomjakushin2, Petřı́ček3 et al. 2011Phys. Rev. B232371View full textAdd to dashboardCite

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Structural modulation, hole distribution, and hole-ordered structure of the incommensurate composite crystal(Sr2Cu2
Gotoh
¹
,
Yamaguchi
²
,
Takahashi
³

et al. 2003
Phys. Rev. B
28
2
24
0
View full text Add to dashboard Cite

Structural modulation, hole distribution, and hole-ordered structure of the incommensurate composite crystal(Sr2Cu2
Gotoh
¹
,
Yamaguchi
²
,
Takahashi
³

et al. 2003
Phys. Rev. B
28
2
24
0
View full text Add to dashboard Cite

Structural evolution of one-dimensional spin-ladder compounds Sr14−xCaxCu24
Deng
¹
,
Pomjakushin
²
,
Petřı́ček
³

et al. 2011
Phys. Rev. B
23
2
37
1
View full text Add to dashboard Cite