2000 Fiscal Year Final Research Report Summary
Study on mesoscopic physical phenomenon in many particle systems by electron holography
| Project/Area Number |
11650671
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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 |
Physical properties of metals
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| Research Institution | Tohoku University |
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Principal Investigator |
KONNO Toyohiko Tohoku Univ., Institute for Materials Research, Associate Professor, 金属材料研究所, 助教授 (90260447)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Transmission electron microscopy / Electron holography / Clusters / Cluster assemblies / Magnetic properties / Tunneling conductivity / Mesoscopic system |
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| Research Abstract |
We employed Hitach HF-2000 transmission electron microscopy for electron holography experiments. The biprism wire was installed between the two intermediate lenses of the microscope, and several ten to 100 voltages was applied to the wire. Having confirmed the reproducibility of the interference fringes, we first used latex particles of approximately 1μm in diameter as a specimen. Reconstructed phase images exhibited equipotential curves around the particles, which was interpreted to represent the electrostatic field around the particles. Next, we observed Nd-Fe-B alloy powders with the same technique. From the reconstructed phase image, it was concluded that a magnetic flux of approximately 4.1x10^<-14> Wb penetrated into the about 1μm area of the tip of the specimen.
In addition, we synthesized monodispersive Co/CoO cluster assembly using plasma gas condensation (PGC) technique. This cluster assembly exhibited strong uniaxial magnetic anisotropy. The detailed observation on the magnetic relaxation behavior indicated macroscopic quantum tunneling effect is operating below 8K.In addition, CoAl intermetallic alloy clusters were generated by the PGC technique for the first time. By controlling processing conditions, it was possible to change both the composition and size of the clusters. The Co-rich alloy clusters clearly exhibited ferromagnetic behavior.
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