| Project/Area Number |
08505004
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Structural/Functional materials
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| Research Institution | Tohoku University |
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Principal Investigator |
SUMIYAMA Kenji Institute for Materials Research, Tohoku University, Associate Professor, 金属材料研究所, 助教授 (70101243)
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| Co-Investigator(Kenkyū-buntansha) |
TAGAMI Katsutoshi Laboratory of Functional Devices, NEC Co.Ltd.Chief Researcher, 機能デバイス研究所, 主幹研究員
SAKURAI Masaki Institute for Materials Research, Tohoku University, Research Associate, 金属材料研究所, 助手 (80235225)
KONNO Toyohiko J. Institute for Materials Research, Tohoku University, Research Associate, 金属材料研究所, 助手 (90260447)
KAMIYAMA Tomoaki Institute for Materials Research, Tohoku University, Research Associate, 金属材料研究所, 助手 (90005926)
SUZUKI Kenji Institute for Materials Research, Tohoku University, Emeritus Professor, 金属材料研究所, 名誉教授 (10005861)
田上 勝通 日本電気株式会社, 機能デバイス研究所, 主幹研究員
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| Project Period (FY) |
1996 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥56,300,000 (Direct Cost: ¥56,300,000)
Fiscal Year 1998: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1997: ¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1996: ¥47,700,000 (Direct Cost: ¥47,700,000)
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| Keywords | nano cluster / cluster-assembled material / laser abration / plasma-gas-condensation / time-of-flight mass-spectrometry / magnetic materials / magnetoresistance / magneto-optics / 自由クラスター / 磁気抵抗効果 / 磁気光学効果 / 磁性クラスター / 磁性 / グラニュラー膜 / グラニュラー薄膜 |
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| Research Abstract |
We would like to establish the new paradigm, functional-material-fabrication from nano-scale clusters, which correspond to units of functional elements. The summaries of our resarch activities for three years are as follows.
1) We designed and constructed a laser-vaparization type cluster deposition system with a time-of- flight mass spectrometer. The mass-spectrometric studies of transition metal clusters indicate that the clusters consiting of 7,13,15,19 atoms are magic numbers for Fe, Ti, Ta, Nb and Zr, while no marked magic number effect for Ni and Co.
2) We analyzed the Fe-oxide cluster formation process by mass-spectrtometry. The abundnances of Fe_<13>O_8, Fe_<43>O_<20> are much stronger the others'. This feature is confirmed by the first principle molecular orbital calculations.
3) Superparamagnetic to ferromagnetic transition is detected at around 9 nm for mono-dispersive Co clusters produced by plasma-gas-condensation.
4) The assemblies of CoO coated Co clusters show very large tunneling type magnetoresistance. The logarithmic conductivity shows T^<-1> dependence, indicating monodispersivity in the cluster size and uniformity of the CoO layer thickness.
5) XAFS, MCD and Magneto-optical Kerr spectra were observed for Co cluster assembled films. Two monolayered CoO is formed at the cluster surface. In the inner metallic Co cores , fcc is predominant for the cluster size, d= 6 nm. With increasing d from 6 to 13 nm, the volume fraction of hcp increases. The magneto-optical Kerr effect is enhanced at the low wave length region.
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