2000 Fiscal Year Final Research Report Summary
Bulk nano-multilayerd materials produced by the repeated plastic deformat and its physical properties
| Project/Area Number |
09305049
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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 | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
SHINGU P.hides Graduate School of Energy Science Engineering, Kyoto University, Professor, エネルギー科学研究科, 教授 (20026024)
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| Co-Investigator(Kenkyū-buntansha) |
OTSUKI Akira Institute of Advanced Energy, Kyoto University Asistant Professor, エネルギー理工学研究所, 助教授 (10026148)
ISHIHARA Keiichi n. Graduate School of Energy Science Engineering, Kyoto University, Asistant Professor, エネルギー科学研究科, 助教授 (30184550)
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| Project Period (FY) |
1997 – 2000
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| Keywords | nanocrystal / nano structure / mechanical alloying / layer stracture / interface reaction / fine grained structure |
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| Research Abstract |
Nano scale multi-layerd materials of Ag and Fe have been manufactured. This material contains alternate layers of Ag and Fe more than several hundred thousand in number. As one of the characteristic properties of such nanolayerdmaterials ofmagnetic and non-magnetic metals, the giant magnetoresistivity (GMR) has been measured. The GMR for electrical current parallel to the layers is about 8% and for the current perpendicular to the layers is about 45%. The experimental confirmation of such large GMR for the case of current perpendicular to the layers has not been, as far as the authors' knowledge, reported previously. Similar multi-layerd materials for the Cu and Fe system has also been manufactured and GMR has also been confirmed. The mechanical strength in tension experiment have been carried out for these materials. The ultimate tensile strength as high as 1.5 GPa have been obtained when the layer thickness is less than about 50 nano meters. The average layer thickness for these materials for which the GMR effect have been observed were in the range of 10 to 50 nano-meters. This thickness range is nearly one order of magnitude greater than that for the samples prepared by the gas deposition method. For the purpose of investigation into the reason for such difference in the thickness of layers necessary for the activation of GMR effect, the sputtering method was used to produce nano-layerd materials of Ag and Fe with irregularities in the layer thickness which simulates the present rolling and folding technique. The average layer thickness in this case have been revealed to be greater than for the samples of regularly deposited nano-layerd materials.
From such experimental results, in the scope of the present experiment, the irregularity in the layer thickness is responsible for the occurrence of GMR for relatively large average layer thickness materials.
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