| Project/Area Number |
17360346
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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 |
Structural/Functional materials
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| Research Institution | National Institute for Materials Science |
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Principal Investigator |
OHKUBO Tadakatsu National Institute for Materials Science, Magnetic Materials Center, Group Leader (00242462)
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| Co-Investigator(Kenkyū-buntansha) |
HONO Kazuhiro National Institute for Materials Science, 磁性材料センター, Fellow (60229151)
TAKAHASHI Yukiko National Institute for Materials Science, Magnetic Materials Center, Senior Researcher (50421392)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥15,980,000 (Direct Cost: ¥15,500,000、Indirect Cost: ¥480,000)
Fiscal Year 2007: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2006: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 2005: ¥11,400,000 (Direct Cost: ¥11,400,000)
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| Keywords | FePt / pernendicular magnetic recording / heusler alloy / spin polarization / スピンエレクトロニクス / 磁気記録 / 電子・電気材料 / 解析・評価 |
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| Research Abstract |
To realize the ultra high areal density of magnetic recording system, we studied 1. the synthesis of the FePt perpendicular granular film with narrow size distribution and a small particle size and the relationship between the magnetic properties and their microstructure, 2. the microstructure analysis of CCP-GMR device and 3. the formation of the Heusler alloy with high spin polarization.
1. The synthesis of the FePt perpendicular thin film and the characterization of the magnetic properties and the microstructure of the films: To apply the FePt to the perpendicular magnetic recording media, we investigated the synthesis of the FePt granular film with narrow size distribution and a small particle size. By depositing the MgO underlayer on the amorphous substrate, we made the c-axis oriented FePt granular structure. Furthermore, we made the FePt granular film with 62 nm of the average particle size and 1.7 nm of the size distribution by using the C and SiO_2 as a matrix. However the degr
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ee of order decreases with decreasing the particle size. The small particle size with high degree of order should be realized to the FePt perpendicular recording media. In the perpendicular magnetic recording media, the soft magnetic underlayer below the FePt layer is necessary for the saturate writing. We achieved the low He of 15 mOe and the high magnetic flux density of 1.6 T by the optimization of FeTaC sputtering and annealing conditions.
2. The microstructure analysis of CCP-GMR device : To analyze the microstructure of the CCP-GMR film, we tried the 3 dimensional atom probe of the CCP-GMR device. lb analyze the CCP-GMR device by 3DAP, very sharp needle-like shape sample is necessary. We use the FIB for making such kind of very sharp tip. At this moment, the 3DAP analysis is not successful yet, it is maybe due to the poor conductivity of the sample. It will be solved by laser atom probe.
3. The formation of the Heusler alloy with high spin polarization We searched the Heusler alloy with high spin polarization by the point contact Andreev reflection (PCAR) method. We got P=65 of Co_2Tio_<25>Mno_<75>Sn and P=0.67 of Co_<19>Fe_<0.1>CrGa. The spin polarization value is still low, however these values are the highest among the spin polarization of the Heusler alloy measured by PCAR method. The increase of the spin polarization of the Co_2Ti-<0.25>Mn_<0.75>Sn is due to the Er shift into the middle of the band gap and that of Co_<19>Fe_<0.1>CrGa is due to the increase of the DOS of the up spin. Less
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