Effect of various mechanical deformation techniques on critical current densities of Ag/Bi-2223 tapes

Chen, W.M.; Guo, Yuan; McCaughey, G.; Apperley, M.; Liu, Huan; Dou, Shi Xue

doi:10.1016/s0921-4534(01)00052-1

Cited by 18 publications

(6 citation statements)

References 10 publications

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“…[1] In order to improve the transport properties of these materials they are subjected to large mechanical deformations. These techniques have proven to be effective in raising the superconducting critical current J c of the superconducting tapes, [3][4][5] mainly due to a marked increase in both the meso-texture and the micro-texture, where the latter is related to the orientation of the individual grains regarding the direction in along the mechanical deformation is applied. The combination of the above types of texture gives the macro-texture of the material.…”

Section: Introductionmentioning

confidence: 99%

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: 99%

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

2005

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“…Between the two sintering processes, an intermediate defonnation of NR, P and SR was perfonned with reduction rate from 0 % to about 35 %. The optimum reduction rates with the maximum J c of tapes appeared at 22%, 25% and 21 % for SR-, P-and NR-tapes, respectively [8,9]. To compare the three deformation methods, the three samples with maximum J c for SR-, P-and NRtapes were chosen for pinning force study.…”

Section: Methodsmentioning

confidence: 99%

“…SR was a special deformation technique that a sample is held between two spring-steel strips (i.e, 'sandwiched'), and the 'sandwich' was rolled. SR processing developed in the recent years was found to be a useful intermediate deformation method, but has not been thoroughly studied yet [8][9][10]. To compare the differences among the three deformations, we fabricated Ag/Bi-2223 tapes by using the above three methods.…”

Section: Introductionmentioning

confidence: 99%

Effect of various mechanical deformation techniques on pinning force densities in Ag/Bi-2223 tapes

Chen¹

2002

AIP Conference Proceedings

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Ag/Bi-2223 tapes were fabricated using the Powder-In-Tube method, involyH1ĩ ntermediate deformation techniques of sandwich rolling (SR), pressing (P) and nQl1l1~r olling (NR). Magnetic field B depen:lence of J c was measured. Depending 6rt:~~' relationship between )c and B, the irreversible magnetic field Birr was determineli)lIl..W: pinning force density F was calculated. The experimental results showed that self-fiel%~;lb was linear with the relative density for SR-, P-and NR-tapes. Our experimental resftltss upport that NR-, P-, andSR-tapes have a same sort of pinning center and the interme#l~tl; deformation processing cannot change property of pinning centers, but can effectth §'" pinning force strength. Our experimental results also support that sandwich rolling istMb est technique for fabricating Ag/Bi-2223 tapes.

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“…Among high temperature superconducting cuprates, the 2223 phase of Bi-based system has a critical temperature as high as 110 K. The 2223 phase with a stoichiometry of (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10 , synthesized at high temperature is a complex compound. The growth morphology of the 2223 phase with solid state reactions mainly depends on synthesis methods, in addition to the properties of precursors and sintering processing [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Phase development and kinetics of the 2223 phase relate to the synthesis processing [16][17][18][19][20][21][22][23][24][25], as well.…”

Section: Introductionmentioning

confidence: 99%

Precursor Size Effects on Kinetics Parameters of Bi-2223 Growth

Chen¹,

Yavuz²,

Kambe³

2009

TOSUPERJ

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The Bi-2223 phase growth was studied on the view growth Kinetics and described by using suggested kinetic equations, and the kinetics parameters of the 2223 growth were experimentally determined. The precursor particle size effect on Bi-2223 phase growth was studied, as well. Precursors in this experiment were made by four different techniques with different particle sizes, and samples were sintered at same temperature for different sintering time. For the four different precursors, the amount of 2223 phase in the reactant was determined by analysis of X-ray diffraction. Experimental results were analyzed in the view of 2223 phase growth kinetics. Particle size dependence of the mean lifetime of 2212 and 2223 phases were studied. And the effects of special area of precursor particle on 2223 crystal growth were also analyzed. The velocity of the 2223 phase growth was investigated, which was found to be dependent on both the precursor particles' diameter and its total surface area. The velocity of the 2223 phase decomposition was determined, as well. The optimum sintering time t max and maximum amount of 2223 phase were calculated, and they were found to be dependent on the mean lifetime of 2212 and 2223 phases. When the particle size decreases, the optimum sintering time decreases, and the maximum amount of 2223 phase increases.

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Effect of various mechanical deformation techniques on critical current densities of Ag/Bi-2223 tapes

Cited by 18 publications

References 10 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 various mechanical deformation techniques on pinning force densities in Ag/Bi-2223 tapes

Precursor Size Effects on Kinetics Parameters of Bi-2223 Growth

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