Reversible melting and equilibrium phase formation of (Bi, Pb)2Sr2Ca2Cu3O10

Giannini, E.; Savysyuk, I.; Garnier, Vincent; Passerini, Reynald; Toulemonde, Pierre; Flükiger, R.

doi:10.1088/0953-2048/15/11/316

Cited by 26 publications

(17 citation statements)

References 40 publications

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“…In spite of this success, this technique has not been used to prepare tapes or multifilament materials at an industrial scale because it was thought that any melting would decompose the Bi 2223 phase and a long period of annealing at a lower temperature would be necessary to recover this phase; long annealing and even a partial melting of chemical precursors have been used to obtain the Bi 2223 phase. Recently, experiments have again shown that this phase can be rapidly recomposed after melting, in agreement with the previous work on magnetic texturing [30,31]. All these results indicate the existence, above the liquidus temperature, of unmelted crystals acting as crystal growth nuclei.…”

Section: Bi 2223supporting

confidence: 89%

Texturing by cooling a metallic melt in a magnetic field

Tournier

Beaugnon

2009

Science and Technology of Advanced Materials

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Processing in a magnetic field leads to the texturing of materials along an easy-magnetization axis when a minimum anisotropy energy exists at the processing temperature; the magnetic field can be applied to a particle assembly embedded into a liquid, or to a solid at a high diffusion temperature close to the melting temperature or between the liquidus and the solidus temperatures in a region of partial melting. It has been shown in many experiments that texturing is easy to achieve in congruent and noncongruent compounds by applying the field above the melting temperature T m or above the liquidus temperature of alloys. Texturing from a melt is successful when the overheating temperature is just a few degrees above T m and fails when the processing time above T m is too long or when the overheating temperature is too high; these observations indicate the presence of unmelted crystals above T m with a size depending on these two variables that act as growth nuclei. A recent model that predicts the existence of unmelted crystals above the melting temperature is used to calculate their radius in a bismuth melt.

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Section: Bi 2223supporting

confidence: 89%

Texturing by cooling a metallic melt in a magnetic field

Tournier

Beaugnon

2009

Science and Technology of Advanced Materials

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“…The unit-cell parameters were calculated regarding an orthorhombic unit cell and the obtained values a = 5.410 Å, b = 5.413 Å, and c = 37.152 Å are in line with those reported elsewhere for the same compound [15][16][17]. The occurrence of grains with platelet-like structure in Bi-based materials is well known, as reported previously in our samples [9,12].…”

Section: Resultssupporting

confidence: 88%

Experimental and theoretical study of transport properties in uniaxially pressed (Bi,Pb)2Sr2Ca
García-Fornaris
¹
,
Muné
²
,
Suzuki
³

et al. 2010
Physica C: Superconductivity
3
0
0
0
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a b s t r a c tExperimental and theoretical studies on the magnetic field dependence of the electrical resistance RðB a Þ and the transport noise (TN) in polycrystalline high-T c superconductors subjected to different uniaxial compacting pressures were conducted. X-ray diffraction rocking curves were performed in different surfaces of the samples in order to investigated the degree of texture. The results indicated an improvement of the degree of texture with increasing the uniaxial compacting pressure. In theoretical simulations of the data, the polycrystalline superconductors were described as a series-parallel array of Josephson devices. The intergranular magnetic field is described within the framework of the intragranular fluxtrapping model and the distribution of the grain-boundary angles is assumed to follow the Rayleigh statistical function. The proposed model describes well the experimental magnetoresistance RðB a Þ data. We have found that the behavior of the RðB a Þ curves changes appreciably when different uniaxially compacting pressures are applied to the sample and such a changes are reproduced by the model when different grain-boundary angles distributions are used. In addition, changes in the RðB a Þ dependence have their counterparts in the experimental transport noise signals.

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“…However, intrinsic limits to this route seem to come from the formation mechanisms where the transient liquid assisting the Bi,Pb(2223) formation is not stable and results in a poor structural homogeneity. E. Giannini et al showed that it is possible to form the Bi,Pb(2223) phase from a liquid close to the equilibrium conditions following a reversible melting of the Bi,Pb(2223) phase exactly in the same way as J. Noudem et al did in bulk samples [39]. Then, Bi2223 intrinsic nuclei exist in the melt.…”

Section: Ag-sheated Tapes Of Bi2sr2ca2cu3o8+xmentioning

confidence: 75%