Control of the Nd422 second phase for the improvement of the critical current density in Nd-Ba-Cu-O superconductors

H. Kojo, S. I. Yoo, Naomichi Sakai, Masato Murakami

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Abstract

Effects of size and volume fraction of the Nd4Ba2Cu2O10 (Nd422) second phase on the critical current density (Jc) were studied for the Nd-Ba-Cu-O bulk superconductors fabricated by an oxygen-controlled-melt-growth (OCMG) process. The size of the Nd422 second phase trapped in NdBa2Cu3Oy (Nd123) superconducting matrix was controlled using two different precursors of Nd123-Nd422 powders and the melt-quenched powders. Finer Nd422 second phase with an average diameter of 1-2μm was obtained in the sample fabricated from the mixture of Nd123-Nd422 precursors when the initial Nd422 powders of less than 1μm was employed. The Jc was significantly improved especially in low field by refining the Nd422 second phase. While a small amount of Nd422 addition increases the Jc in low field without sacrificing the Jc near the fishtail peak, the peak effect was drastically depressed by increasing the volume fraction.

Original languageEnglish
Pages (from-to)83-86
Number of pages4
JournalSuperlattices and Microstructures
Volume21
Issue numberSuppl A
Publication statusPublished - 1997
Externally publishedYes

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Critical current density (superconductivity)
Powders
Superconducting materials
critical current
current density
Volume fraction
refining
Refining
Oxygen
oxygen
matrices

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

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abstract = "Effects of size and volume fraction of the Nd4Ba2Cu2O10 (Nd422) second phase on the critical current density (Jc) were studied for the Nd-Ba-Cu-O bulk superconductors fabricated by an oxygen-controlled-melt-growth (OCMG) process. The size of the Nd422 second phase trapped in NdBa2Cu3Oy (Nd123) superconducting matrix was controlled using two different precursors of Nd123-Nd422 powders and the melt-quenched powders. Finer Nd422 second phase with an average diameter of 1-2μm was obtained in the sample fabricated from the mixture of Nd123-Nd422 precursors when the initial Nd422 powders of less than 1μm was employed. The Jc was significantly improved especially in low field by refining the Nd422 second phase. While a small amount of Nd422 addition increases the Jc in low field without sacrificing the Jc near the fishtail peak, the peak effect was drastically depressed by increasing the volume fraction.",
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T1 - Control of the Nd422 second phase for the improvement of the critical current density in Nd-Ba-Cu-O superconductors

AU - Kojo, H.

AU - Yoo, S. I.

AU - Sakai, Naomichi

AU - Murakami, Masato

PY - 1997

Y1 - 1997

N2 - Effects of size and volume fraction of the Nd4Ba2Cu2O10 (Nd422) second phase on the critical current density (Jc) were studied for the Nd-Ba-Cu-O bulk superconductors fabricated by an oxygen-controlled-melt-growth (OCMG) process. The size of the Nd422 second phase trapped in NdBa2Cu3Oy (Nd123) superconducting matrix was controlled using two different precursors of Nd123-Nd422 powders and the melt-quenched powders. Finer Nd422 second phase with an average diameter of 1-2μm was obtained in the sample fabricated from the mixture of Nd123-Nd422 precursors when the initial Nd422 powders of less than 1μm was employed. The Jc was significantly improved especially in low field by refining the Nd422 second phase. While a small amount of Nd422 addition increases the Jc in low field without sacrificing the Jc near the fishtail peak, the peak effect was drastically depressed by increasing the volume fraction.

AB - Effects of size and volume fraction of the Nd4Ba2Cu2O10 (Nd422) second phase on the critical current density (Jc) were studied for the Nd-Ba-Cu-O bulk superconductors fabricated by an oxygen-controlled-melt-growth (OCMG) process. The size of the Nd422 second phase trapped in NdBa2Cu3Oy (Nd123) superconducting matrix was controlled using two different precursors of Nd123-Nd422 powders and the melt-quenched powders. Finer Nd422 second phase with an average diameter of 1-2μm was obtained in the sample fabricated from the mixture of Nd123-Nd422 precursors when the initial Nd422 powders of less than 1μm was employed. The Jc was significantly improved especially in low field by refining the Nd422 second phase. While a small amount of Nd422 addition increases the Jc in low field without sacrificing the Jc near the fishtail peak, the peak effect was drastically depressed by increasing the volume fraction.

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