| Project/Area Number |
21740266
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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 | Nihon University |
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Principal Investigator |
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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 |
¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
Fiscal Year 2011: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2010: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2009: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Keywords | エキゾチック超伝導 / マルチギャップ超伝導 / 不純物効果 / 熱伝導率 / プラストレーション / 超音波測定 / 中性子散乱 / スピン分子 / 軌道整列 / 軌道揺らぎ / フラストレーション / GeCo_2O_4 / GeFe_2O_4 / 超音波 / 超伝導ギャップ対称性 / Lu_2Fe_3Si_5 / YNi_2B_2C / YCoC / 電荷密度分布マッピング / Lu2Fe3Si5 / DyNi2B2C / TmNi2B2C / La3Ni2B2N3 |
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| Research Abstract |
This project performed studies of exotic superconductivity and geometrical frustration effects in several iron-family-based compounds. And remarkable research results were obtained especially in the study of exotic superconductivity in the iron silicide Lu_2Fe_3Si_5, and the study of geometrical frustration effects in The spinel cobaltite GeCo_2O_4.
The iron silicide superconductor Lu_2Fe_3Si_5 has three-dimensional multiband structure which is demarcated from the multiband structure in the iron arsenide superconductors. This project performed study of non-magnetic impurity effects on the superconductivity, and magneto-thermal transport experiments in Lu_2Fe_3Si_5. And we obtained research results which strongly suggest the sign-reversed multigap superconductivity.
The spinel cobaltite GeCo_2O_4 is a geometrically-frustrated magnet with orbital degrees of freedom, where an antiferromagnetic transition occurs despite the dominance of ferromagnetic exchange interactions. Inelastic neutron scattering experimets in GeCo_2O_4 observed a typical frustration effect of molecular spin excitations. Furthermore, ultrasound velocity measuremets in GeCo_2O_4 observed elastic anomalies driven by the molecular spin excitations, and elastic anomalies which strongly suggest the occurrence of magnetic-field induced orbital order-order transitions.
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