2005 Fiscal Year Final Research Report Summary
Hydrothermal Synthesis of Magnetic Single Crystals in Thermally and Chemically Stable Reaction Fields of One-Dimensional Nano Space
| Project/Area Number |
15310068
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Tohoku University |
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Principal Investigator |
KYOTANI Takashi Tohoku University, Institute of Multidisciplinary Research for Advanced Materials, Professor, 多元物質科学研究所, 教授 (90153238)
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| Co-Investigator(Kenkyū-buntansha) |
ORIKASA Hironori Tohoku University, Institute of Multidisciplinary Research for Advanced Materials, Research Associate, 多元物質科学研究所, 助手 (90375163)
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| Project Period (FY) |
2003 – 2005
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| Keywords | carbon nanotube / magnetic material / nanowire / high-density magnetic recoding media / hydrothermal synthesis / electroplating |
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| Research Abstract |
By chemical vapor deposition of propylene over an anodic aluminum oxide (AAO) film, not only the outer surface but also the inner surface of AAO nanochannels can be fully covered with carbon. The carbon-coated nanochannels can be used as a template in hydrothermal treatment that requires sever alkaline conditions. In the first year we reported our attempt at the synthesis of single crystal nanorods by hydrothermal reaction of nickel compounds in the cavity of the carbon-coated nanochannels and demonstrated that hydrothermal synthesis method can be applied to template-based preparation of nano-sized materials. However, we had some difficulty to insert ferromagnetic metal into the nanochannels using this hydrothermal method. Then we found that ferromagnetic metal (Permalloy) was electrochemically deposited on the carbon-coated nanochannels in the AAO layer in an electroplating bath. Moreover, not only soft magnetic alloy such as Permalloy but also hard magnetic materials such as nickel metal were able to be deposited.
In the above electroplating method, Permalloy deposition had never been observed inside the nanotubes, but only on the external surface, when we used the carbon-coated AAO film as a cathode for the electroplating of Permalloy. We then removed only the carbon deposited on the external surface of the AAO film with leaving carbon inside the channels and found metal deposition in the cavity of the nanotubes. This is because electroplating into nano space surrounded by electro-conductive material (carbon) is very difficult. However, for the application of high-density magnetic recoding media, such carbon layer on the external surface should be kept, because the carbon can play a role of a protective and lubricated layer. We thus make every effort to electro-chemically deposit Permalloy in the carbon-coated nanochannels in the AAO and finally have succeeded in such deposition by precisely controlling the electroplating conditions.
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