Texture analysis of Bi-2212 and 2223 tapes and wires by neutron diffraction

Wenk, H. R.; Chateigner, Daniel; Pernet, M.; Bingert, J. F.; Hellstrom, E. E.; Ouladdiaf, B.

doi:10.1016/s0921-4534(96)00561-8

Cited by 18 publications

(18 citation statements)

References 26 publications

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“…The relative averaged deviations RP 1 and Rw 1 (for density values above 1 mrd) are equal to 10.1% and 5.6%, and RP 0 and Rw 0 (for all densities) to 16.9% and 6.8%. These values are fairly low, and compare favorably with recent results on strongly textured compounds having orthorhombic crystal symmetry Wenk et al 1996). The large difference between RP and Rw values arises from the fact that the former factor increases with the texture strength F, which is as high as 86 mrd 2 in our sample.…”

Section: Resultssupporting

confidence: 88%

Polarized EXAFS, distance-valence least-squares modeling (DVLS), and quantitative texture analysis approaches to the structural refinement of Garfield nontronite

Manceau¹,

Chateigner²,

Gates³

1998

Physics and Chemistry of Minerals

148

143

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This paper reports on the new application of polarized extended X-ray absorption fine structure (P-EXAFS) spectroscopy to fine-grained layer silicates taking the Garfield nontronite as a case study. Up to now application of P-EXAFS to structural studies of layer silicates has been restricted to single phyllosilicate crystals Manceau et al. 1990), but we show here that P-EXAFS can rigorously be applied to self-supporting clay films without loss of spatial resolution. The quantitative analysis of P-EXAFS requires however the preparation of highly oriented clay films, the orientation distribution of which can be assessed by texture goniometry. The Fe K-edge linear dichroism measurements were simulated by ab initio EXAFS modeling performed on a nontronite cluster whose structure was refined by distance-valence least-squares calculations. It is shown that ab initio modeling quantitatively accounts for the angular dependence of experimental EXAFS spectra. These calculations allowed for the identification of the fundamental character of single-and multiple-scattering paths of the photoelectron, and the structural interpretation of all spectral features observed up to 6.5 for the in-plane and outof-plane radial structure functions of nontronite. In practice, P-EXAFS measurements allow the determination of the flattening angle of Fe(O,OH) 6 octahedra, cations distribution in the octahedral sheet with an enhanced sensitivity, and differentiation between dioctahedral and trioctahedral structures.

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Section: Resultssupporting

confidence: 88%

Polarized EXAFS, distance-valence least-squares modeling (DVLS), and quantitative texture analysis approaches to the structural refinement of Garfield nontronite

Manceau¹,

Chateigner²,

Gates³

1998

Physics and Chemistry of Minerals

148

143

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“…A first azimuthal scan (ϕ-scan) was operated on the (119) reflection in order to check for specific texture symmetries. As expected for uniaxially deformed materials without subsequent growth, we detected a C ∞ axis of symmetry aligned with the cylinder axis, as reported by other authors [19]. Then, tilt scans (ψ-scans) were performed from ψ = 0…”

Section: Methodssupporting

confidence: 83%

“…Hence, due to the thickness of compounds (0.2-0.3 mm), we do not expect any large influence of the foil on the resulting growing properties, except as a beneficial pressure homogenization due to its larger ductile character. But we systematically observe smaller FWHDs compared to mono-or multifilamentary tapes [19,24,26], which could be interpreted as the effect of the mechanical interaction between Ag and Bi2212 or Bi2223 in Ag-sheathed ribbons. In the CSF process no lateral constraint is applied to the cylindrical powders, which allows the discs to laterally extend and thereby promotes a stronger texturation.…”

Section: Discussionmentioning

confidence: 74%

Sinter-forging of strongly textured Bi2223 discs with largeJ_cs: nucleation and growth of Bi2223 from Bi2212 crystallites

Guilmeau

Chateigner

Noudem

2002

Supercond. Sci. Technol.

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Dense Bi2223 superconductor discs with a highly oriented structure were prepared by the sinter-forging method. A detailed investigation of the processing parameters has been carried out on the phase assemblage, the particle size of the calcined precursor powder and the sinter-forging time and temperature. A high transport critical current density, J c , was obtained from a starting powder rich in Bi2212 and secondary phases. Using fine powder, a high degree of orientation, larger than those of multifilamentary tapes, and excellent intergrain connection were observed. The optimal sinter-forging temperature was found to be in the range of 845-850• C and the transport critical current densities reached values of 12 700 A cm −2 at 77 K in self-field. The combination of textural and microstructural investigations testify that a nucleation-growth mechanism from the Bi2212 particles is responsible for the Bi2223 phase formation, rather than an intercalation process.

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Section: Methodssupporting

confidence: 82%

Experimental Corroboration for a Ferrite-Core Model of High-T_c Bulk Superconductor Lenses (Supertrons)

Matsuzawa

Kobayashi

Mochizuki

et al. 1994

Jpn. J. Appl. Phys.

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Dense Bi2223 superconductor discs with a highly oriented structure were prepared by the sinter-forging method. A detailed investigation of the processing parameters has been carried out on the phase assemblage, the particle size of the calcined precursor powder and the sinter-forging time and temperature. A high transport critical current density, J c , was obtained from a starting powder rich in Bi2212 and secondary phases. Using fine powder, a high degree of orientation, larger than those of multifilamentary tapes, and excellent intergrain connection were observed. The optimal sinter-forging temperature was found to be in the range of 845-850 • C and the transport critical current densities reached values of 12 700 A cm −2 at 77 K in self-field. The combination of textural and microstructural investigations testify that a nucleation-growth mechanism from the Bi2212 particles is responsible for the Bi2223 phase formation, rather than an intercalation process.

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Texture analysis of Bi-2212 and 2223 tapes and wires by neutron diffraction

Cited by 18 publications

References 26 publications

Polarized EXAFS, distance-valence least-squares modeling (DVLS), and quantitative texture analysis approaches to the structural refinement of Garfield nontronite

Polarized EXAFS, distance-valence least-squares modeling (DVLS), and quantitative texture analysis approaches to the structural refinement of Garfield nontronite

Sinter-forging of strongly textured Bi2223 discs with largeJ_cs: nucleation and growth of Bi2223 from Bi2212 crystallites

Experimental Corroboration for a Ferrite-Core Model of High-T_c Bulk Superconductor Lenses (Supertrons)

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Texture analysis of Bi-2212 and 2223 tapes and wires by neutron diffraction

Cited by 18 publications

References 26 publications

Polarized EXAFS, distance-valence least-squares modeling (DVLS), and quantitative texture analysis approaches to the structural refinement of Garfield nontronite

Polarized EXAFS, distance-valence least-squares modeling (DVLS), and quantitative texture analysis approaches to the structural refinement of Garfield nontronite

Sinter-forging of strongly textured Bi2223 discs with largeJcs: nucleation and growth of Bi2223 from Bi2212 crystallites

Experimental Corroboration for a Ferrite-Core Model of High-Tc Bulk Superconductor Lenses (Supertrons)

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Sinter-forging of strongly textured Bi2223 discs with largeJ_cs: nucleation and growth of Bi2223 from Bi2212 crystallites

Experimental Corroboration for a Ferrite-Core Model of High-T_c Bulk Superconductor Lenses (Supertrons)