2005 Fiscal Year Final Research Report Summary
Research on nanoscopic magnet including 3d transition metals
| Project/Area Number |
15510089
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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 |
Nanostructural science
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| Research Institution | Yokohama National University |
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Principal Investigator |
ICHIYANAGI Yuko Yokohama National University, Physics, Assistant, 工学研究院, 助手 (90240762)
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| Project Period (FY) |
2003 – 2005
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| Keywords | nanotechnology / nanoparticles / transition metal oxide / magnetization / nanomedicine |
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| Research Abstract |
Magnetic properties of nanoparticles including 3d transition metals were investigated. Prepared samples were Co3O4, Mn3O4,Mn2O3, Ni-ferrite, NiZn-ferrite, Mn-ferrite, Mg-ferrite surrounded by amorphous SiO2.
1.Co3O4 nanoaprticles with 3 nm in size showed ferromagnetic behavior below blocking temperature Tb, though bulk crystal has antiferromagnetic below TN=33 K.
2.Magnetization of Mn3O4 nanoparticles showed drastic change depending on particle sizes. For 2.5 nm- sample was considered to be ordered periodically than other samples though the size was extremely small. This phenomenon could be confirmed by the results of XAFS measurements.
3.NiO nanoparticles were produced by annealing Ni(OH)2 monolayer-nanoclusters above 973 K in air. In the magnetization measurements superparamagnetic or ferromagnetic behaviors were observed and characteristic properties of NiO nanoparticles were confirmed.
4.Nil-xZnFe2O4(2<x<1) mixed ferrite nanoparticles encapsulated with amorphous SiO2 were prepared. Particle sizes were controlled to range from 2.6 nm to 33.7 nm by heat treatment, and the particle size dependence of saturation magnetization Ms was investigated for the x=0.5 region. The Ms value decreased abruptly for particle sizes. The relationship between saturation magnetizations Ms and the Zn concentration was almost similar to that between the saturation magnetization and Ni-Zn ferrite bulk crystal, however, the absolute values of Ms of the nanoparticles were about 30 % smaller than those of bulk crystal
5.XAFS measurements and thermal analysis were also performed for all the samples. Functionalizing of medical application was newly considerd.
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