The Effect of Ca<sub>2</sub>PbO<sub>4</sub> Addition on Superconductivity in a Bi-Sr-Cu-O System

Uzumaki, Takuya; Yamanaka, Kazunori; Kamehara, Nobuo; Niwa, Koichi

doi:10.1143/jjap.28.l75

Cited by 94 publications

(16 citation statements)

References 5 publications

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“…An alternative route for the formation of Bi2223 would be to start the reactions from calcined powders composed of Bi2212 and secondary phases such as Ca 2 PbO 4 , CaCuO 3 or CuO [5][6][7][8][9]. This would allow the plate-like grains to reorient more easily because of the large amount of liquid phase.…”

Section: Introductionmentioning

confidence: 99%

Sinter-forging of strongly textured Bi2223 discs with largeJ_cs: nucleation and growth of Bi2223 from Bi2212 crystallites

Guilmeau

Chateigner

Noudem

2002

Supercond. Sci. Technol.

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Dense Bi2223 superconductor discs with a highly oriented structure were prepared by the sinter-forging method. A detailed investigation of the processing parameters has been carried out on the phase assemblage, the particle size of the calcined precursor powder and the sinter-forging time and temperature. A high transport critical current density, J c , was obtained from a starting powder rich in Bi2212 and secondary phases. Using fine powder, a high degree of orientation, larger than those of multifilamentary tapes, and excellent intergrain connection were observed. The optimal sinter-forging temperature was found to be in the range of 845-850• C and the transport critical current densities reached values of 12 700 A cm −2 at 77 K in self-field. The combination of textural and microstructural investigations testify that a nucleation-growth mechanism from the Bi2212 particles is responsible for the Bi2223 phase formation, rather than an intercalation process.

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Section: Introductionmentioning

confidence: 99%

Sinter-forging of strongly textured Bi2223 discs with largeJ_cs: nucleation and growth of Bi2223 from Bi2212 crystallites

Guilmeau

Chateigner

Noudem

2002

Supercond. Sci. Technol.

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“…The formation of the 2223 phase is believed to proceed by a reaction between Bi 2 Sr 2 Ca 1 Cu 2 O y (hereafter referred to as "2212"), alkaline earth cuprate phases, and a liquid phase. [8][9][10][11][12][13][14][15][16][17] One of the most effective ways to make a nearly phase-pure 2223 microstructure is to blend Pbdoped 2212 powder with a mixture of Ca 2 CuO 3 and CuO. 15,16 This so-called "two-powder" mixture reacts quickly to the 2223 phase, leaving only small (Ca,Sr) 2 CuO 3 particles as the principal residual second phase.…”

Section: Introduction 1234567891011121314151617mentioning

confidence: 99%

Controlled decomposition and reformation of the 2223 phase in Ag-clad (Bi, Pb)₂Sr₂Ca₂Cu₃O_x tapes and its influence on the microstructure and critical current density

et al. 1996

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The decomposition of almost fully reacted (Bi, Pb)2Sr2Ca2Cu3Ox (BSCCO-2223) tapes caused by heating in 1 atm of pure O2 at 825 °C has been studied. It was found that partially decomposing 2223 tapes to a mixture of Bi2Sr2Ca1Cu2Oy, (Ca, Sr)2PbO4, and other secondary phases reduced the critical current density (77 K, 0 T) from ∼20 kA/cm2 to nearly zero. Reheating the tapes in 7.5% O2 restored the 2223 phase and, while there was some degradation of the 2223 grain alignment due to residual secondary phase growth, the critical current density was also restored to nearly its original value. We hypothesize that such a decomposition/reformation process can be useful in increasing the connectivity and relative density of polycrystalline 2223, by encouraging the formation of a liquid phase which heals residual cracks in the BSCCO core.

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“…The difficulty in preparing the high-T~ phase revealed that an understanding of the formation of high-T~ phase is prerequisite for the fabrication of superconductors containing pure high-To phase with high quality. The formation mechanism of the high-To phase was extensively discussed by many authors [6][7][8][9][10][11]. Even 0957 4522 ~; 1996 Chapman & Hall though different approaches were made so far, many points concerning the formation mechanism of the high-To phase are still obscure.…”

Section: Introductionmentioning

confidence: 99%

A new model for the formation of high-T c phase in superconductive (Bi, Pb)2Sr2Ca2Cu3O x glass-ceramics

Khaled

Komatsu

Matusita

et al. 1996

J Mater Sci: Mater Electron

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The formation mechanism of the high-To phase through the glass-ceramic route and the role of Pb on the formation of this phase have been investigated. It was found that a new compound with the chemical composition Pb2Sr3 xCaxCuOv (x = 1.8) precipitates at around 550°C. This phase is stable up to 800°C, where it begins to decompose, and at 850°C it completely disappears. It was found that some part of the released Pb diffuses into the 2212 phase leading to the formation of Pb-containing 2212 phase, (Bi,Pb)2Sr2CaCu2Ox. On the other hand, an endothermic peak, probably arising from the melting of (Bi,Pb)2Sr2CaCu2Ox phase or melting at grain boundaries containing Pb 2+, was observed at 856°C only in Pb-containing samples that were heat treated. The liquid phase attributed to the endothermic peak may enhance the formation of high-Tc phase (2223 phase). The growth kinetics for the high-To phase were analysed using the Johnson-MehI-Avrami equation; the results indicate that the growth of the high-To phase is controlled by a diffusion process and the activation energy for its formation in the initial stage (shorter than 96 h) is 576_+45 kJ tool -1

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The Effect of Ca₂PbO₄ Addition on Superconductivity in a Bi-Sr-Cu-O System

Cited by 94 publications

References 5 publications

Sinter-forging of strongly textured Bi2223 discs with largeJ_cs: nucleation and growth of Bi2223 from Bi2212 crystallites

Sinter-forging of strongly textured Bi2223 discs with largeJ_cs: nucleation and growth of Bi2223 from Bi2212 crystallites

Controlled decomposition and reformation of the 2223 phase in Ag-clad (Bi, Pb)₂Sr₂Ca₂Cu₃O_x tapes and its influence on the microstructure and critical current density

A new model for the formation of high-T c phase in superconductive (Bi, Pb)2Sr2Ca2Cu3O x glass-ceramics

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The Effect of Ca2PbO4 Addition on Superconductivity in a Bi-Sr-Cu-O System

Cited by 94 publications

References 5 publications

Sinter-forging of strongly textured Bi2223 discs with largeJcs: nucleation and growth of Bi2223 from Bi2212 crystallites

Sinter-forging of strongly textured Bi2223 discs with largeJcs: nucleation and growth of Bi2223 from Bi2212 crystallites

Controlled decomposition and reformation of the 2223 phase in Ag-clad (Bi, Pb)2Sr2Ca2Cu3Ox tapes and its influence on the microstructure and critical current density

A new model for the formation of high-T c phase in superconductive (Bi, Pb)2Sr2Ca2Cu3O x glass-ceramics

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Product

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The Effect of Ca₂PbO₄ Addition on Superconductivity in a Bi-Sr-Cu-O System

Sinter-forging of strongly textured Bi2223 discs with largeJ_cs: nucleation and growth of Bi2223 from Bi2212 crystallites

Sinter-forging of strongly textured Bi2223 discs with largeJ_cs: nucleation and growth of Bi2223 from Bi2212 crystallites

Controlled decomposition and reformation of the 2223 phase in Ag-clad (Bi, Pb)₂Sr₂Ca₂Cu₃O_x tapes and its influence on the microstructure and critical current density