Subgrain formation, 211 particle segregation and high-angle 90° boundaries in melt-grown YBaCuO

Diko, P.; Todt, V.R.; Miller, Dean J.; Goretta, K. C.

doi:10.1016/s0921-4534(97)00113-5

Cited by 39 publications

(43 citation statements)

References 14 publications

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“…Subgrain formation during crystal growth has been observed in other contexts, such as YSZ growth on polycrystalline Al 2 O 3 , liquid phase recrystallization of Si on SiO 2 , melt‐grown RE‐Ba‐Cu‐O (RE = Y, Sm, Nd), local compositional disorder strain‐induced subgrains in CaCu 3 Ti 4 O 12 , sublimation‐mediated growth of SiC crystals, and the formation of siderite (FeCO 3 mineral) on calcite (CaCO 3 mineral) . Subgrain formation from growth in several of these cases is the result of crystallographic growth rate gradients, which does not appear to be the case in the present work.…”

Section: Discussionmentioning

confidence: 96%

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Single crystal growth of CoTi₂O₅ by solid state reaction synthesis

et al. 2019

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Materials in single crystal form are often sought after because the absence of grain boundaries can result in unique properties relative to the polycrystal, but producing these materials is typically a slow and complex process. In this work, pseudo single crystals of the pseudobrookite compound CoTi2O5 were synthesized by solid‐state reaction from a duplex grain mixture of CoTiO3 and TiO2. The size of the crystallites was >250 µm. The transformation and subsequent microstructural evolution of the CoTi2O5 was studied by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), and X‐ray diffraction (XRD). A novel growth mechanism was identified whereby a single crystal CoTi2O5 front advances simultaneously along multiple CoTiO3/TiO2 diphasic boundaries. The single crystal domains were composed of subgrains approximately 5 µm in diameter; differences in the subgrain size and misorientation were related to the growth mechanism and the initial grain size of the duplex CoTiO3–TiO2 mixture. CoTi2O5 is a little characterized compound, and this study represents the most significant microstructural study of CoTi2O5 to date. The findings may be applied to similar pseudobrookite compounds such as MgTi2O5 and Al2TiO5.

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Section: Discussionmentioning

confidence: 96%

“…Subgrain structures are occasionally observed in ceramics due to deformation or solidification, but subgrains resulting from solid‐state reactions are unusual. The mechanisms underlying subgrain formation during CoTi 2 O 5 single crystal formation are discussed.…”

Section: Introductionmentioning

confidence: 99%

Single crystal growth of CoTi₂O₅ by solid state reaction synthesis

et al. 2019

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“…Several groups have observed the phenomenon of macrosegregation of Y-211 inclusions in bulk YBCO superconductors [13][14][15][16][17]. Chow et al [13] reported that the number density of Y-211 particles increases continuously with distance from the position of the seed towards the edge of the large grain sample in Pt-doped YBCO superconductors.…”

Section: Introductionmentioning

confidence: 99%

The processing and properties of single grain Y–Ba–Cu–O fabricated from graded precursor powders

Zhai

Shi

Durrell

et al. 2013

Supercond. Sci. Technol.

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The preparation of single grain, Y-Ba-Cu-O (YBCO) bulk superconductors by top-seeded melt-growth (TSMG) usually involves precursor powders that contain a uniform distribution of the constituent YBa 2 Cu 3 O 7−δ (Y-123) and Y 2 BaCuO 5 (Y-211) phase compounds. However, it has been observed that the concentration of Y-211 particles in the fully melt processed superconducting bulk increases significantly with distance from the seed, which results in a degradation of superconducting properties towards the edge and bottom of the sample. Here we investigate the effect of preparing bulk YBCO superconductors by TSMG using spatially graded Y-211/Y-123 precursor powder. The graded precursor bulks were prepared with a maximum composition of 40 wt% Y-211 in the vicinity of the seed, which decreased to 30 wt% and then 20 wt% towards the bottom and edge of the green body. Standard samples were melt processed from precursor powders containing 30 wt% Y-211 to enable comparison. The field trapping ability, T c and J c , of three graded and two standard samples were investigated and compared statistically. The distribution of Y-211 particles along different growth directions of the samples was analysed, and any crystallographic misorientation was investigated. The observed distribution of Y-211 particles in YBCO is explained qualitatively by trapping/pushing theory, and its correlation with the superconducting properties of the melt processed bulk samples has been analysed. Finally, the practical feasibility of the graded technique is evaluated.

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“…In further experiments, we decided to use an addition of 0.95 wt% BaCeO 3 , since at this concentration the Y211 particles are effectively refined and the pushing effect does not cause as much macroscopic inhomogeneity of the Y211 concentration as in the samples with a higher BaCeO 3 addition (Figure 11). Addition of 0.95 wt% BaCeO 3 is equivalent to addition of 0.5 wt% CeO 2 which is two times lower than the standard amount of 1.0 wt% CeO 2 34‐37 …”

Section: Resultsmentioning

confidence: 94%

Influence of addition of nanosize barium cerate on the microstructure and properties of top‐seeded melt growth YBCO bulk superconductors

et al. 2020

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Subgrain formation, 211 particle segregation and high-angle 90° boundaries in melt-grown YBaCuO

Cited by 39 publications

References 14 publications

Single crystal growth of CoTi₂O₅ by solid state reaction synthesis

Single crystal growth of CoTi₂O₅ by solid state reaction synthesis

The processing and properties of single grain Y–Ba–Cu–O fabricated from graded precursor powders

Influence of addition of nanosize barium cerate on the microstructure and properties of top‐seeded melt growth YBCO bulk superconductors

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Subgrain formation, 211 particle segregation and high-angle 90° boundaries in melt-grown YBaCuO

Cited by 39 publications

References 14 publications

Single crystal growth of CoTi2O5 by solid state reaction synthesis

Single crystal growth of CoTi2O5 by solid state reaction synthesis

The processing and properties of single grain Y–Ba–Cu–O fabricated from graded precursor powders

Influence of addition of nanosize barium cerate on the microstructure and properties of top‐seeded melt growth YBCO bulk superconductors

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Single crystal growth of CoTi₂O₅ by solid state reaction synthesis

Single crystal growth of CoTi₂O₅ by solid state reaction synthesis