| Project/Area Number |
14540539
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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 |
機能・物性・材料
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| Research Institution | University of Hyogo (2004)
Himeji Institute of Technology (2002-2003) |
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Principal Investigator |
YAMADA Jun-ichi University of Hyogo, Graduate School of Material Science, Department of Material Science, Associate Professor, 大学院・物質理学研究科, 助教授 (90191311)
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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 |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | Organic Superconductor / Intermolecular Interaction / Non-TCF Donor / Extension of σ-Bond Framework / Reduction of π-System / Effective Cyclotron Mass / Magnetoresistance / Superconducting Hydrate / 反強磁性超伝導体 / 反強磁性金属 / π-d相互作用 / HOMO / 結晶構造 / 国際情報交換 / アメリカ合衆国 / 有効質量 / シューブニコフ-ド・ハース振動 / 磁気抵抗 / 磁場誘起超伝導体 / 化学修飾法 / 有機伝導体 / ハイブリッド / 電荷移動物質 / フェルミ面 / 磁性アニオン / 反強磁性体 / フランス |
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| Research Abstract |
Tetrachalcogenafulvalene(TCF) donors are no longer essential to the production of organic superconductors, excluding fullerene superconductors. Indeed, the non-TCF-containing π-electron donor BDA-TTP [which contains the bis-fused 1,3-dithiol-2-ylidene(BDY) unit instead of the TCF unit as a π-electron system] and the 1,3-dithiol-2-ylidene (DT)-based π-donor DODHT do give superconducting salts. Our molecular design strategy for these π-donors is based on the following requirements : (i)the extension of the σ-bond framework and (ii)the reduction of the π-system. These requirements are thought to lead to a decrease of intermolecular interaction, which would be crucial in achieving superconductivity. In addition to their superconductivity, we have found the outstanding physical properties of the SbF_6 and FeCl_4 salt of BDA-TTP. β-(BDA-TTP)_2SbF_6 was proved to have the largest effective cyclotron mass (12.4±1.1 m_e) yet found in organic superconductors. This result indicates that the electron-electron interaction is probably enhanced in the BDA-TTP superconductor. Angular dependent and variable-temperature magnetoresistance(MR) measurement for β-(BDA-TTP)_2FeCl_4 under pressure showed an abrupt drop of MR. A similar anomaly in MR has been reported in κ-(BETS)_2FeBr_4 and λ-(BETS)_2FeCl_4, which exhibit magnetic-field-induced superconductivity. Similar to the superconductors β"-(DODHT)_2X (X=AsF_6 and PF_6) at 16.5 kbar, the β"-(DODHT)_2BF_4・H_2O hydrate was found to undergo an superconducting transition under an applied pressure of 15.5 kbar. The common noticeable feature of the three DODHT superconductors is that they all show a variety of pressure-induced conducting behaviors, including the insulating (or semiconducting), metallic, and superconducting phases. In this way, we succeeded in finding a series of non-TCF-based organic superconductors with notable features.
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