2004 Fiscal Year Final Research Report Summary
Development of Organic Superconductors by Reduction of Intermolecular Interaction
| 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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| Keywords | Organic Superconductor / Intermolecular Interaction / Non-TCF Donor / Extension of σ-Bond Framework / Reduction of π-System / Effective Cyclotron Mass / Magnetoresistance / Superconducting Hydrate |
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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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Research Products
(122 results)
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[Journal Article] Tetrachloroferrate (III) Salts of BDH-TTP [2,5-Bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene] and BDA-TTP [2,5-Bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene] : Crystal Structures and Physical Properties2002
Author(s)
K.Kikuchi
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Journal Title
J.Solid State Chem.(Special Issue) 168
Pages: 503-508
Description
「研究成果報告書概要(和文)」より
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[Journal Article] Tetrachloroferrate (III) Salts of BDH-TTP [2,5-Bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene] and BDA-TTP [2,5-Bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene] : Crystal Structures and Physical Properties2002
Author(s)
K.Kikuchi
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Journal Title
J.Solid.State Chem. (Special Issue) 168
Pages: 503-508
Description
「研究成果報告書概要(欧文)」より
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