2005 Fiscal Year Final Research Report Summary
Lorentz Microscopy of nano-scale magnetic particles embedded in metal matrices
| Project/Area Number |
16560576
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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 | Yokohama National University |
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Principal Investigator |
TAKEDA Mahoto Yokohama Nat.Univ., Dept Eng., Associate Professor, 大学院・工学研究院, 助教授 (30188198)
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| Co-Investigator(Kenkyū-buntansha) |
ENDO Takao Yokohama Nat.Univ., Dept Eng., Professor, 名誉教授 (40018007)
HIROI Zenji Univ.of Tokyo, Inst.Solid State Physics, Professor, 物性研究所, 教授 (30192719)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Cu-Co alloy / Lorentz Microscopy / nano-scale magnetic particles / magnetic domain structure |
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| Research Abstract |
Domain structure of nano-scale magnetic particles embedded in copper matrices were studied by bright-field TEM, HRTEM and Lorentz microscopy, together with VSM and SQUID measurements. BFTEM showed that the coherent cobalt particles were transformed into incoherent precipitates at 50nm in size. After loosing the coherency, the octahedral precipitates entered into rapid coarsening. The present Lorentz microscopy detected the deviation of the incident electron beam due to the magnetization of cobalt particles. The magnitude of the deviating angles was estimated as twice as large as the value derived from a simple Lorentz force model. Lorentz EM also shows that incoherent precipitates were composed of four magnetic domains, each of which has a magnetization oriented to [100].
SQUID measurements show that the magnetic properties of the specimens followed in a superparamagnetic M-T curve. But the property of the particles gradually changed into ferromagnetic. The magnetization curve once decreased just after a short annealing. Then the M curve increased with the annealing. The highest coersivity attained at the period that two coherent particles were coupled.
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Research Products
(1 results)
