| Project/Area Number |
08454218
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | THE UNIVERSITY OF ELECTRO-COMMUNICATIONS |
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Principal Investigator |
NOGAMI Takashi THE UNIVERSITY OF ELECTRO-COMMUNICATIONS,PROFESSOR, 電気通信学部, 教授 (80029280)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIDA Takayuki THE UNIVERSITY OF ELECTRO-COMMUNICATIONS,ASSOCIATE PROFESSOR, 電気通信学部, 助教授 (00232306)
曽 和平 電気通信大学, 電気通信学部, 助教授 (60293114)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥7,900,000 (Direct Cost: ¥7,900,000)
Fiscal Year 1997: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 1996: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Keywords | Molecule-based ferromagnet / Transition-metal complex / Magnetic property / Crystal structure / Ferromagnetic interaction / Weak ferromagnetism / SQUID measurement / Stable organic radical / 有機強磁性体 / 磁気的性質 / 結晶構造解析 / 弱い強磁性体 / 配位化合物 / TEMPO / μSR / ピリミジン錯体 / 遷移金属 / 重水素置換 |
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| Research Abstract |
(1) Magnetic Properties of Organic Radicals
Magnetic properties of 165 kinds of TEMPO derivatives (ArCH=N-TEMPO,Ar=aryl group) were studied by SQUID Intermolecular ferromagnetic interactions were found for 52 radicals. Thus, the intermolecular ferromagnetic interaction were found to be not a rare phenomenon. Eight kinds of radicals showed bulk ferromagnetic transitions below 0.4 K.We proposed that the ferromagnetic interaction was caused by the spin-polarization mechanism via beta-hydrogens. This mechanism was supported by MO calculations and NMR measurements. Spontaneous magnetization was observed below T_c by means of zero-field muSR measurements. In order to elevate the transition temperatures, magnetic properties of pi-conjugated NO radicals were studied. NO radicals possessing acridine skeleton showed the intermolecular ferromagnetic interaction which was caused through the overlaps of pi-electron clouds (McConell model).
(2) Magnetic Properties of Pyrimidine-Transition Metal Complexes
In order to study the magnetic interactions of transition-metal ions coordinated to meta-positions of an aromatic ring, magnetic properties of various pyrimidine-transition metal complexes were studied. It was found that coordination modes rather than coordination positions (meta-position) determine the magnetic interactions. In the case of Cu^<2+> an axial/equatorial coordination gave rise to the ferromagnetic interaction, and an equatorial/equatorial coordination did the antiferromagnetic interaction. When we adopted inorganic anions of small sizes, sevral complexes showed the behavior of a weak ferromagnetism. (pyrimidine)_2CoX_2 (X=Cl, Br) has a chiral crystal structure, and showed the behavior of the weak ferromagnetism.
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