Influence of the compacting pressure on the dependence of the critical current with magnetic field in polycrystalline (Bi–Pb)2Sr2Ca2Cu3Ox superconductors

Muné, P.; Govea-Alcaide, E.; Jardim, R. F.

doi:10.1016/s0921-4534(02)02060-9

Cited by 60 publications

(42 citation statements)

References 20 publications

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“…[2] In a previous work, we have described a systematic study concerning the influence of uniaxial compacting pressure on the general superconducting properties of polycrystalline (BiPb) 2 Sr 2 Ca 2 Cu 3 O 10+δ (Bi-2223) samples. [6] By performing measurements of critical current density as a function of applied magnetic field, J c (B a ), we have observed three different superconducting levels: the superconducting grains, the superconducting clusters, and the weak links. It was found that properties of the last two levels are very sensitive to the compacting pressure, mostly due to changes in the grain boundary properties.…”

Section: Introductionmentioning

confidence: 97%

“…Details of the sample preparation process are described elsewhere. [6] Here, before the last heat treatment, the powders were uniaxially pressed at different compacting pressures ranging from ∼ 90 to ∼ 600 MPa (see Table I), and the typical dimensions of the pellets were d = 10 mm in diameter and h = 1 mm in height. The last heat treatment of the pellets was performed in air at 845 • C for 40 h followed by slow cooling.…”

Section: Introductionmentioning

confidence: 99%

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Normal-state properties of uniaxially pressed Bi1.65Pb0.35Sr2Ca2Cu3O10+delta ceramics

2005

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We have studied the effects of the uniaxial compacting pressure on the physical properties of polycrystalline Bi 1.65 Pb 0.35 Sr 2 Ca 2 Cu 3 O 10+δ (Bi-2223) superconductors. Powders of this material were pressed at different uniaxial compacting pressures ranging from ∼ 90 to ∼ 600 MPa and heat-treated at the same temperature. A characterization of samples by using Scanning Electron Microscopy and X-ray diffractometry indicated an appreciable improvement of the degree of texture with increasing pressure. The temperature dependence of the electrical resistivity ρ(T) exhibits a T -linear behavior at temperatures higher than T * ∼ 235 K. The deviation of ρ(T) from the linear behavior below T * indicates the opening of the pseudogap, a feature confirmed by magnetic susceptibility measurements performed in powder samples. From linear fittings of the normal-state electrical resistivity we were able to separate contributions to ρ(T) arising from both the grain misalignment and microstructural defects. The results suggest that the grain orientation and the connectivity between them are improved with increasing compacting pressure. Also, based on the linearity of the electrical resistivity data both the transport electron-phonon coupling constant, λ tr , and the mean free path, l, were estimated. We have found that in the sample with the highest degree of texture λ tr ∼ 0.53, a value comparable with the one obtained in Bi-2223 single crystals. However, the result for l ∼ 12.7Å at 300 K, in the same ceramic sample, is close to 3 times lower than the single crystal value. The influence of the intergranular electrical resistivity in determining band-theory parameters was analyzed within the framework of a current conduction model for granular superconducting materials.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Normal-state properties of uniaxially pressed Bi1.65Pb0.35Sr2Ca2Cu3O10+delta ceramics

2005

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“…Mune et al [5] had found that the grain properties were very similar in all samples but that the J c (B a ) dependence was very sensitive to the compaction pressure and the experimental data were evaluated within the framework of a three-level superconducting system. Govea et al [6] investigated the resistive transition of nearly single-phase Bi 1.65 Pb 0.35 Sr 2 Ca 2 Cu 3 O 10+δ samples subjected to uniaxial compaction at different pressures under low applied magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

Effect of Compaction Pressure on Structural and Superconducting Properties of Bi-2223 Superconductors

Kocabaş

Gökçe

Çiftçioğlu

et al. 2009

J Supercond Nov Magn

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In this work, effects of compaction pressure on the structural and superconducting properties of BSCCO ceramic superconductors were investigated. The study was carried out on two systems which were, System I: Bi 1.7 Pb 0.3 Sr 2 Ca 2 Cu 3 O y and System II: Bi 1.6 Pb 0.3 Ag 0.1 Sr 2 Ca 2 Cu 3 O y , respectively. Ceramic powders were prepared by conventional solid-state reaction method and sintered at 850°C after compaction at five different pressures in the 150-750 MPa range. Critical temperatures of samples were determined by resistivity-temperature determinations made by four-point probe method in liquid nitrogen conditions. XRD analysis was conducted by powder X-ray diffraction method. Morphology of the grains present in the samples were determined by using scanning electron microscope (SEM) photographs at 2 K× and 2.5 K× magnifications for System I and System II, respectively. Sintered densities of the superconducting ceramics were measured by Archimedes water displacement method and unit cell parameters were additionally obtained from XRD data. T c values for System I was determined to be in the 109-115 K with sample D having the highest T c of 115 K while T c varied in the 104-109 K range and sample B had the highest T c value of 109 K for System II. The transition width, which is a sign of the purity of the samples, was determined to be narrow for both systems. The data obtained from X-ray diffraction measurements have shown that 2223 high-T c phase was dominant in both systems. The determination of the optimum pellet compaction pressure for BSCCO ceramic superconductors was the main purpose of this work. The results of this work indicated that compaction at around 450 MPa improves the superconducting and structural properties of the BSCCO ceramic superconductors.

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“…After the last heat treatment, the pellets were reground again and the resulting powder was used to be consolidated by the spark plasma sintering method. The above procedure assures that the obtained Bi-2223 precursor powder consists of the high-T c Bi-2223 phase, as discussed elsewhere [7].…”

Section: Introductionmentioning

confidence: 91%

“…The standard dc four-probe method was used in all measurements of the electronic transport properties of the pellets [7], i.e. the electrical resistivity as a function of temperature, ρ(T ), and the critical current density measured at T = 77 K and at zero applied magnetic field, J c (0).…”

Section: Introductionmentioning

confidence: 99%

Spark plasma sintering of Bi1:65Pb0:35Sr2Ca2Cu3O10+ : improving microstructural features for practical applications

García-Fornaris¹,

Calzada²,

Govea-Alcaide³

et al. 2014

Proceedings of the 13th International Symposium on Multiscale, Multifunctional and Functionally Graded Materials

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The grain boundaries in polycrytalline high-T c superconductors constitute a limitation for the use of these materials in several devices. In order to verify the effect of the consolidation process in the microstructural features, powders of single-phase Bi 1.65 Pb 0.35 Sr 2 Ca 2 Cu 3 O 10+δ (Bi-2223) were consolidate by the spark plasma sintering (SPS) method at 750• C. The SPS samples exhibited very high density but are oxygen deficient, as inferred from the electrical resistivity, ρ(T ), data. The samples were then subjected to a post-annealing heat treatment in air, at 750• C, and for different times, t pa = 0, 5, 30 min, and 40 hours. From the X-ray diffraction analysis we have found that SPS post-annealed samples for t pa > 5 min show the presence of an extra phase identified as the infinite layer compound with general formula Ca 1−x Sr x CuO 2 . Irrespective of the presence of this additional phase, the superconducting properties, including the superconducting critical current at 77 K, of the post-annealed SPS samples are optimized for t pa = 5 min. The combined properties of the samples obtained by the SPS technique make them suitable for practical applications as superconducting fault current limiters (SFCL).

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Influence of the compacting pressure on the dependence of the critical current with magnetic field in polycrystalline (Bi–Pb)2Sr2Ca2Cu3Ox superconductors

Cited by 60 publications

References 20 publications

Normal-state properties of uniaxially pressed Bi1.65Pb0.35Sr2Ca2Cu3O10+delta ceramics

Normal-state properties of uniaxially pressed Bi1.65Pb0.35Sr2Ca2Cu3O10+delta ceramics

Effect of Compaction Pressure on Structural and Superconducting Properties of Bi-2223 Superconductors

Spark plasma sintering of Bi1:65Pb0:35Sr2Ca2Cu3O10+ : improving microstructural features for practical applications

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