2001 Fiscal Year Final Research Report Summary
Nano-scale Crystallized Ferromagnetic Dots Formed by Electron Injection and their Magnetic Properties
| Project/Area Number |
12650300
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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 |
Electronic materials/Electric materials
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| Research Institution | Faculty of Engineering and Resource Science, Akita University |
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Principal Investigator |
ISHIO Shinji Department of Materials Science and Engineering, Faculty of Engineering and Resource Science, Akita University, Professor, 工学資源学部, 教授 (90134006)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Hitosi Department of Materials Science and Engineering, Faculty of Engineering and Resource Science, Akita University, Professor, 工学資源学部, 助教授 (00270843)
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| Project Period (FY) |
2000 – 2001
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| Keywords | electron injection / magnetic force microscope / ferromagnetic dot / domain structure / magnetic recording media |
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| Research Abstract |
In ultra high-density magnetic recording at more than 1000Gbit/inch2, the new concept for recording media, in which recording bits are highly stabilized against thermal fluctuation, is required. The patterned medium composed of ferromagnetic dot arrays is one of the candidates for such media. Nano-scale electron injection into metallic thin films can make ferromagnetic dots arrays, and hence it is expected as the technique to realize ultra high-density recording media. In this research, the electron injection technique was applied to make nano-scale ferromagnetic dot arrays and magnetic wall-pinning sites in amorphous and crystalline films. The magnetic domain structures of these dots were studied.
(1) Nano-scale ferromagnetic dot formation by electron injection
Nano-scale electron injection was carried out by using scanning probe microscope (SPM). The experimental conditions for nano-scale dot formation were investigated for amorphous FeZr and crystalline FePt, CoCrPt and CoPt films. Na
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no-scale dots were formed through Townsend discharge in air, Joule heating and recrystallization of films. The minimum size of dot is 50nm in diameter and the minimum width of thin line is lOOnm.
(2) In-situ MFM domain observation of magnetic domain in magnetic field
In-situ MFM observation apparatus in magnetic field was designed and fabricated. The maximum magnetic field is 6 kOe, which is applied parallel to the film plane. The spatial resolution is less than lOnm. The domain structure depends on both samples and dot formation conditions. The magnetic domain wall pinning due to dot array is observed in FePt film and the single domain structure is in FeZr dots.
(3)Magnetic microstructure of high density recording media
The magnetic microstructure was observed MFM and analyzed using LLG simulation. The origin of medium noise in in-plane recording media is attributed to both magnetic vortex structure and magnetic divergent structure, which arise from magnetic fluctuations in transition region. Less
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