Construction of Organic Magnetic Metals and Magnetic Composits using Spin-Polarized Donors
| Project/Area Number |
13440206
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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 | Ibaraki University |
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Principal Investigator |
IZUOKA Akira Ibaraki University, College of Science, Professor, 理学部, 教授 (90193367)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥13,300,000 (Direct Cost: ¥13,300,000)
Fiscal Year 2003: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2002: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2001: ¥9,400,000 (Direct Cost: ¥9,400,000)
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| Keywords | nanoparticle / Magnetism / ESR / radical / magnetic metal / spin-polarized donor / 金ナノ粒子 / ニトロキシド / 超共役 / ドナー / 交差共役 / 強磁性 / 有機磁性金属 |
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| Research Abstract |
The research project was carried out syntheses of the cross-conjugated and hyper-conjugated spin-polarized donor molecules and preparation of their adsorbed gold nanoparticles in order to construct the magnetic organic-inorganic nano-composites.
Several Nano-composites consisted of gold nanoparticle were prepared by the chemical adsorption of some nitroxide radicals on the surface of ca. 4 nm gold nanoparticles which were synthesized by reduction of HAuCl_4 at the presence of tetraocyl ammonium bromide. The obtained solid samples of the nanoparticles showed singlet ESR signals that the line widths were within 1.5 〜 30 mT. Among them, the nanoparticles functionallized by the spin polarized donor typed nitronyl nitroxide exhibits extraordinarily broad signal. Molecular orbital calculation of this radical indicated a large spin polarization at the site of sulfur atom that is the attaching site to the gold surface. As the concentration of the spin polarized donor radical on the surface of nanoparticles was reducing by mixing a diamagnetic ligand, the line width became small. These results indicated that the line broadening of ESR signal rationalized by considering of the assistant of the conduction electrons of gold nanoparticle for the spin relaxation, although the line width of ESR signals generally correlates with the spin-spin relaxation among the localized spins of radicals.
While the interaction of the conduction electrons with localized spins was recognized for the nano-composite samples, it was found by the measurement of magnetic susceptibility that the magnetic interaction between radicals on gold nanoparticles was paramagnetic. The researches for the construction of the magnetic nano-composite are in progress.
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Report
(4 results)
Research Products
(16 results)
