| Project/Area Number |
16360355
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | NATIONAL INSTITUTE FOR MATERIALS SCIENCE (2005)
Tohoku University (2004) |
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Principal Investigator |
TOGANO Kazumasa NATIONAL INSTITUTE FOR MATERIALS SCIENCE, Superconducting Materials Research Center, Research Fellow, 超伝導材料研究センター, 特別研究員 (60361169)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Kazuo Tohoku University, Institute of Materials Research, Professor, 金属材料研究所, 教授 (30143027)
ORIMO Shinichi Tohoku University, Institute of Materials Research, Associate Professor, 金属材料研究所, 助教授 (40284129)
BADICA Petre Tohoku University, Institute of Materials Research, Research Associate, 金属材料研究所, 助手 (30372311)
KUMAKURA Hiroaki NATIONAL INSTITUTE FOR MATERIALS SCIENCE, Superconducting Materials Research Center, Director, 超伝導材料研究センター, センター長 (90354307)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥14,100,000 (Direct Cost: ¥14,100,000)
Fiscal Year 2005: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 2004: ¥10,100,000 (Direct Cost: ¥10,100,000)
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| Keywords | Superconductor / Magnesium Diboride / Critical current density / Mechanical milling / Pulsed-laser deposition / YAG / Diffusion reaction / MgB2超伝導体 / メカニカルアロイング / レーザー蒸着法 / 粉末法 / MgB_2超伝導体 |
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| Research Abstract |
For the practical applications of MgB_2 superconductor, which has very high T_c of 39K, it is necessary to improve the characteristics in applied magnetic field. This would be achieved by the improvement of present fabrication processes based on nanometer size structural control or the development of new processes based on different idea. The purpose of this work is to establish the basis for the improvement of properties by applying non-equilibrium processes such as mechanical milling and laser deposition technique. For the milling process, we investigated systematically the influence of starting powder, atmosphere, milling condition, heat treatment condition and nanometer-size particles addition. By optimizing these parameters, the J_c dependence on magnetic field was improved probably due to the introduction of strain into the grain. We also fabricated tapes by PIT process in which the milled powders were encased in a metal sheath and cold worked into a final size. For laser deposition, we developed a new pulsed vapor deposition system using Nd-YAG laser which might have several advantages over conventional excimer laser ; low cost, easy operation, high stability and reduced space. The MgB_2 film synthesized by using this system showed excellent H_<c2>(0) value of 41T, which might be caused by non-equilibrium state of excess C-doping into B site. In this work, we also developed a new process for the fabrication of MgB_2 wire based on interface diffusion in the composite of Fe-Mg alloy and B layers. The MgB_2 layer has dense structure free from MgO inclusion, which is difficult to achieve by the conventional PIT process. We also discovered 8K superconductivity in Li_2Pd_3B which is the first boride superconductor with Li as a constituent.
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