| Project/Area Number |
09355023
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Structural/Functional materials
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| Research Institution | Kitami Institute of Technology (1999)
Tohoku University (1997-1998) |
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Principal Investigator |
MAEDA Hiroshi Department of Materials Science, Professor, 工学部, 教授 (00281981)
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| Co-Investigator(Kenkyū-buntansha) |
張 平祥 豊橋技術科学大学, 工学部, 助教授 (70314086)
KIKUCHI Michio Tohoku University, Institute for Materials Research, Research Associate, 金属材料研究所, 助手 (30204837)
SATO Mitsunori Department of Materials Science, Professor, 工学部, 教授 (40281878)
HIRAGA Kenji Tohoku University, Institute for Materials Research, Professor, 金属材料研究所, 教授 (30005912)
WATANABE Katsuo Tohoku University, Institute for Materials Research, Associate Professor, 金属材料研究所, 助教授 (30143027)
ZHANG Ping-Xiang Toyohashi University of Technology, Associate Professor
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| Project Period (FY) |
1997 – 1999
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| Keywords | Bi2223 & Bi2212 / V-doping / Ag-sheathed multifilamentary tape / Sr-V-O barrier / critical current density / a.c.loss / magnetic melt processing / crystal orientation |
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| Research Abstract |
Bi oxide superconductors (Bi2212. Bi2223) are the most important candidates for practical use. For practical applications high critical current density Jc and low a.c.losses will be required.
we found that a considerable amount of V added into Bi oxide superconductors greatly enhances the Bi2223 formation without any degradation of Tc. The added V exists as Sr6V2O11 (SVO) plate-like particles, which play an important role to promote the formation. Using V doped Bi2223 powder, we prepared Ag-sheathed tapes with monofilament and multifilaments by the powder-in-tube method. Jc values increase with increasing the V content up to 0.15 and this tendency becomes more and more conspicuous for multifilametary tapes. Furthermore, we prepared Ag-sheathed Bi2223 multifilamentary tapes with a layer of SVO barrier outside and inside each filament. The SVO barrier layers have no bad effects on the critical current density Jc of the tapes and decrease a.c.losses obviously. Jc increases obviously in the tapes with barriers both inside and outside each filament. Therefore, the SVO will be one of the important candidates for barriers to reduce a.c.losses.
Magnetic melt processing (MMP) or crystal growth in high magnetic field have been applied to Bi2212 bulks and thick tapes in order to achieve high crystal orientation. For them no techniques have been developed so far. Magnetic field tends to orient Bi2212 grains with the c-axis parallel to it and the degree of texture increases notably with increasing the magnetic field. Therefore, the Jc values of Bi2212 bulks and thick tapes are improved obviously. This shows that MMP is a promising method to prepare Bi2212 bulks and thick tapes with high grain orientation and high Jc values.
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