| Project/Area Number |
14550002
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | University of Tsukuba |
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Principal Investigator |
YOSHIZAKI Ryozo The University of Tsukuba, Graduate School of Pure and Applied Sciences, Professor, 大学院・数理物質科学研究科, 教授 (70011137)
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| Co-Investigator(Kenkyū-buntansha) |
IKEDA Hiroshi The University of Tsukuba, Graduate School of Pure and Applied Sciences, Assistant Professor, 大学院・数理物質科学研究科, 講師 (50272167)
KOYANO Tamotsu The University of Tsukuba, Graduate School of Pure and Applied Sciences, Assistant Professor, 大学院・数理物質科学研究科, 講師 (00215419)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2004: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2003: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2002: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Bi-2201 phase / Bi-2212 phase / superconducting whisker / second peak effect / flux-flow state / whiskers in nanometer size / BPSLCO / area control growth of whiskers / 銅酸化物高温超伝導体 / キャリヤー数の最適化 / セカンドピーク / ウィスカーの成長 / 選択的にウィスカーの成長 / 高温超伝導 / Bi系銅酸化物 / ヒゲ結晶成長 / 単結晶 / 磁化ヒステリシス |
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| Research Abstract |
We have studied about two themes ; growth and control of superconducting whiskers in Bi-2212 phase and growth and characterization of high-quality and higher Tc superconductors in Bi-2201 phase.
In the growth of whiskers, we obtained many results successfully. The distinguished results are as follows, (1)growth of high quality whiskers with our original powder-compaction method, (2)observed new second peak effect in Jc at high temperatures above 70 K, (3)area control growth of whiskers, and (4)growth of nanometer-size whiskers. These results will open the way for superconducting whiskers to be used in superconducting cables as fillers with high-quality superconducting elements and in superconducting wirings in nanometer scale electronic elements.
In the other theme of growth control with higher Tc in Bi-2201 phase, we succeeded to obtain the superconductors with Tc higher than 40 K in single crystals by adopting a Pb and La co-doping method, which is almost new trial in this field. The highest Tc obtained in our study is 43.8 K in zero-resistance temperature, which is the world record ever obtained in Bi-2201 phase. The crystal structures are still orthorhombic but the modulation periods are elongated by three times compared to the undoped materials. As serendipity of the research, we observed the superconductivity with the onset temperature of about 80 K in Bi-2201 phase. The origin of the superconductivity is still under investigation now.
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