Study on odd frequency Cooper pairs at junction interfaces in tunneling phenomena
| Project/Area Number |
21740259
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Condensed matter physics II
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| Research Institution | Kagoshima University |
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Principal Investigator |
SHIGETA Iduru 鹿児島大学, 大学院・理工学研究科, 助教 (30370050)
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| Project Period (FY) |
2009 – 2011
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| Project Status |
Completed (Fiscal Year 2011)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2011: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2010: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2009: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Keywords | ハーフメタル / 超伝導体 / アンドレーエフ反射 / スピン分極率 / 奇周波数クーパー対 / 磁性 / 超伝導材料・素子 / 低温物性 / トンネル現象 / 物性実験 |
|---|
| Research Abstract |
In this work, I have studied on odd frequency Cooper pairs at junction interfaces between a ferromagnet and a superconductor. I have clarified several topics as follows:
1. I synthesized Heusler alloys Co_<2-x> Fe_xMnSi and Ru_<2-x> Fe_xCrSi, which are expected as half-metal by the first-principles band calculations. Those materials are candidates of half-metal.
2. The spin polarization of Co_<2-x> Fe_xMnSi is independent of composition x and is equal to approximately 50%.
3. The spin polarization of Ru_<2-x> Fe_xCrSi is maximum value of 63% in the case of x=1. 8.
4. I succeed in fabricating fully-epitaxial NbN/Co_2MnSi and NbN/Co_2FeSi bilayers and those nano-junctions in order to trap the odd frequency Cooper pairs.
5. I observed a large zero-bias peak in differential conductance of NbN/Co_2MnSi nano-junctions. The phenomenon are not explained by the modified Blonder-Tinkham-Klapwijk(BTK) model and indicates generations of odd frequency pairs at the junction interface.
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Report
(4 results)
Research Products
(54 results)
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[Journal Article] Ferromagnetism and spin-glass transitions in the Heusler compounds Ru_<2-x> Fe_xCrSi2009
Author(s)
M. Hiroi, T. Rokkaku, K. Matsuda, T. Hisamatsu, I. Shigeta, M. Ito, T. Sakon, K. Koyama, K. Watanabe, S. Nakamura, T. Nojima, T. Nakano, L. Chen, T. Fujiwara, Y. Uwatoko, H. Manaka, N. Terada
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Journal Title
Physical Review
Volume: B79
Issue: 22
DOI
Related Report
Peer Reviewed
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[Presentation] Ru_2CrSiの物性について2011
Author(s)
内田かおり, 廣井政彦, 伊藤昌和, 重田出
Organizer
第117回日本物理学会九州支部例会
Place of Presentation
佐賀大学本庄キャンパス(佐賀県佐賀市)
Year and Date
2011-12-03
Related Report
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[Presentation] Spin polarization of Fe-rich ferromagnetic compounds in Ru_<2-x> Fe_xCrSi Heusler alloys2010
Author(s)
I. Shigeta, O. Murayama, T. Hisamatsu, A. Brinkman, A. A. Golubov, Y. Tanaka, M. Ito, H. Hilgenkamp, M. Hiroi
Organizer
The 9th International Conference on Spectroscopies in Novel Superconductors(SNS2010)
Place of Presentation
Fudan University, Shanghai, China
Related Report
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[Presentation] Spin polarization of Fe-rich ferromagnetic compounds in Ru_<2-x>Fe_xCrSi Heusler alloys2010
Author(s)
I.Shigeta, O.Murayama, T.Hisamatsu, A.Brinkman, A.A.Golubov, Y.Tanaka, M.Ito, H.Hilgenkamp, M.Hiroi
Organizer
The 9th International Conference on Spectroscopies in Novel Superconductors (SNS2010)
Place of Presentation
Fudan University, Shanghai, China
Related Report
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[Presentation] Magnetic Properties of Ru-rich Ru_<2-x>Fe_xCrZ (Z=Si, Ge)2010
Author(s)
M.Hiroi, S.Nakashima, K.Nakao, T.Rokkaku, M.Ito, I.Shigeta, H.Manaka, N.Terada
Organizer
International Conference on Superconductivity and Magnetism 2010 (ICSM2010)
Place of Presentation
Porto Bello Hotel, Antalya, Turkey
Related Report
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[Presentation] Spin polarization measurements of Ru_<2-x> Fe_xCrSi Heusler alloys in Fe-rich ferromagnetic region by Andreev reflection2009
Author(s)
I. Shigeta, O. Murayama, T. Hisamatsu, M. Ito, M. Hiroi
Organizer
New Directions of Superconducting Nanostructures 2009(NDSN2009)
Place of Presentation
Environmental Studies Hall, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
Related Report
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