Influence of Y2BaCuO5 particles on the growth morphology of peritectically solidified YBa2Cu3O7−x

Schmitz, Georg J.; Laakmann, J.; Wolters, C.; Rex, S.; Gawalek, W.; Habisreuther, T.; Bruchlos, G.; Görnert, P.

doi:10.1557/jmr.1993.2774

Cited by 82 publications

(28 citation statements)

References 10 publications

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“…27,35,36 Planar growth stability theory 37,38 and computer simulations of the yttrium concentration distribution around 211 particles 39 have been applied on the length scale of formation of the dendrites observed in the present study (i.e., over dimensions of a few microns). Such a process has been reported by other authors, albeit on a different scale.…”

Section: Resultsmentioning

confidence: 99%

Anisotropic growth morphology and platelet formation in large grain Y–Ba–Cu–O grown by seeded peritectic solidification

Cardwell

Chow

1998

J. Mater. Res.

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The characteristic platelet-like structure of large grain superconducting Y-Ba-Cu-O fabricated using peritectic solidification techniques has been documented widely as a key microstructural feature of this material. The platelet formation mechanism is investigated via a detailed comparison of the difference in morphology of YBa 2 Cu 3 O 72d (123) growth fronts propagating along different lattice directions. The development of YBa 2 Cu 3 O 72d dendrites between the growth front and local Y 2 BaCuO 5 (211) particles is observed to be a key feature of the growth mechanism along all directions. Dendrites broaden rapidly for growth fronts propagating along the c-axis due to the enhanced growth rate of Y-Ba-Cu-O in the a-b plane to yield a uniform, regular growth morphology. Dendrite broadening is inhibited for grain growth along the a-b directions, however, due to the slower growth rate along the c-axis, which yields an irregular extended growth front. Growth along the a͞b direction commonly results in the formation of regions consisting of 123 dendrites which may connect 211 particles. Continued solidification of the 123 phase in such regions results in the development of platelet structures perpendicular to the crystallographic c-axis in the YBa 2 Cu 3 O 72d phase matrix which may impede the flow of current through the grain in the superconducting state.

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Section: Resultsmentioning

confidence: 99%

Anisotropic growth morphology and platelet formation in large grain Y–Ba–Cu–O grown by seeded peritectic solidification

Cardwell

Chow

1998

J. Mater. Res.

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“…For example, 211 grains which are entrapped in the solidification front influence the microstructure of melt-textured 123. 26,27 Hence their orientation could compete with the general growth direction and could induce secondary nucleation, another factor inducing deviation with respect to the imposed gradient. However, in the present case there is no orientation of 211 trapped grains, this is in fact rather natural as a thermal gradient itself has no energy to orient particles except perhaps through convective forces.…”

Section: A Texturing 211: Unfavorable Parametersmentioning

confidence: 99%

Secondary-phase orientation probed by EPR:mY2BaCuO5sin
Pellerin
¹
,
Simon
²
,
Odier
³

et al. 1997
Phys. Rev. B
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Textured YBa 2 Cu 3 O 7Ϫx samples have been studied by electronic paramagnetic resonance. EPR spectroscopy allows us to analyze the Y 2 BaCuO 5 second phase present as inclusions in the YBa 2 Cu 3 O 6 textured matrix. All samples were deoxygenated in order to limit the skin effect due to conductivity. This is applied to samples textured according to different techniques. Preferential orientation of these particles according to the 123 matrix can be observed. For instance, if texturing under a magnetic field, the particular Y 2 BaCuO 5 orientation is observed of the b 211 axis ͑bϭ7.132 Å͒ parallel to c 123 and to the magnetic field direction. By appropriate calculations from initial spectra, the fraction of preferred orientation of these Y 2 BaCuO 5 grains can be quantified. This orientation comprises 16Ϯ2 % of the Y 2 BaCuO 5 weight for texturing under a magnetic field, presently one of the highest values obtained. It involves the longest size of Y 2 BaCuO 5 elongated grains lying in YBa 2 Cu 3 O 6 planes, facilitating the texturation process. Texturing on Y 2 O 3 by the modified melt textured growth method leads to a preferential orientation of Y 2 BaCuO 5 grains too, but in another direction, i.e., b 211 perpendicular to c 123 . There is no Y 2 BaCuO 5 preferential orientation if texturing with a thermal gradient or on a monocrystalline MgO substrate. This type of analysis can be applied easily to other systems ͑nanocomposites, dispersoids, etc.͒, providing that the signal of the secondary phase can be clearly separated from the signal of the primary one.

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“…Nevertheless, these interactions seem to be relevant for the growth of the 123 system. In fact, Schmitz et al [23] have shown that some 123 bridges tend to be formed between the solidifying front and the neighbouring 211 particles. We stress here that bridge formation could be anisotropic along the a-b planes.…”

Section: Origins Of the Pattern Formationmentioning

confidence: 99%

Dependence of Off-Diagonal Components of χ⁽³⁾ on Substrate Temperature of Epitaxially Grown Vanadyl Phthalocyanine Films

Fang¹,

Kohama²,

Hoshi³

et al. 1993

Jpn. J. Appl. Phys.

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Optically polarized light micrographs of isothermally melt-textured DyBa 2 Cu 3 O 7−δ compounds (with 15 wt% Dy 2 O 3 addition) are presented to show evidence for pattern formation of DyBa 2 Cu 3 O 5 particles in DyBa 2 Cu 3 O 7−δ grains. Different types of pattern were observed and were understood as arising from the crystal growth mechanism of 123 melt-textured materials. In an appendix, the case of patterns in magnetically textured samples is discussed.

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Influence of Y₂BaCuO₅ particles on the growth morphology of peritectically solidified YBa₂Cu₃O_7−x

Cited by 82 publications

References 10 publications

Anisotropic growth morphology and platelet formation in large grain Y–Ba–Cu–O grown by seeded peritectic solidification

Anisotropic growth morphology and platelet formation in large grain Y–Ba–Cu–O grown by seeded peritectic solidification

Secondary-phase orientation probed by EPR:mY2BaCuO5sin
Pellerin
¹
,
Simon
²
,
Odier
³

et al. 1997
Phys. Rev. B
0
0
0
0
View full text Add to dashboard Cite

Dependence of Off-Diagonal Components of χ⁽³⁾ on Substrate Temperature of Epitaxially Grown Vanadyl Phthalocyanine Films

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Influence of Y2BaCuO5 particles on the growth morphology of peritectically solidified YBa2Cu3O7−x

Cited by 82 publications

References 10 publications

Anisotropic growth morphology and platelet formation in large grain Y–Ba–Cu–O grown by seeded peritectic solidification

Anisotropic growth morphology and platelet formation in large grain Y–Ba–Cu–O grown by seeded peritectic solidification

Secondary-phase orientation probed by EPR:mY2BaCuO5sinPellerin1, Simon2, Odier3 et al. 1997Phys. Rev. B0000View full textAdd to dashboardCite

Dependence of Off-Diagonal Components of χ(3) on Substrate Temperature of Epitaxially Grown Vanadyl Phthalocyanine Films

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Influence of Y₂BaCuO₅ particles on the growth morphology of peritectically solidified YBa₂Cu₃O_7−x

Secondary-phase orientation probed by EPR:mY2BaCuO5sin
Pellerin
¹
,
Simon
²
,
Odier
³

et al. 1997
Phys. Rev. B
0
0
0
0
View full text Add to dashboard Cite

Dependence of Off-Diagonal Components of χ⁽³⁾ on Substrate Temperature of Epitaxially Grown Vanadyl Phthalocyanine Films