2006 Fiscal Year Final Research Report Summary
Microstructure control of nitride magnetoresistor in nano granular type
| Project/Area Number |
17350096
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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 |
Inorganic industrial materials
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| Research Institution | Hokkaido University |
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Principal Investigator |
KIKKAWA Shinichi Hokkaido Univ., Grad. School of Eng., Prof, 大学院工学研究科, 教授 (10127219)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEDA Takashi Hokkaido Univ., Grad. School of Eng., Assistant Prof., 大学院工学研究科, 助手 (60344488)
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| Project Period (FY) |
2005 – 2006
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| Keywords | spin-electronics / ceramics / nano material / inorganic industrial chemistry / magnetic recording / iron nitride / cobalt nitride / granular |
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| Research Abstract |
Magnetic sensors are important for information technology especially in pick up system of hard disk drive. Magnetoresistor with large MR ratio is required for its high sensitivity. Nitrides of post transition metals such as Fe, Co, Ni are thermally metastable to precipitate the ferromagnetic metal particles. Their annealed products would be magnetoresistors in granular type. In the present study, precipitation behavior and magnetoresistance were studied on their sputter deposited thin films in their post annealing.
Iron nitrides, γ'''-FeN_x, (0.5≦x≦0.7) with defect rock-salt type and γ''-FeN_y (0.8≦x≦0.9) with zinc blende type were obtained in reaction sputter deposition at 1Pa and 5Pa of nitrogen pressure, respectively. α-Fe gradually precipitated in their annealing above 450℃. Negative magnetoresistance was observed on the films formed as mixtures with Fe_3N.
Zinc blende CoN film was obtained in a sputter deposition at 5Pa. Its thermal decomposition started at 300℃ through Co_2N and directly to α-Co metal above 350℃. Positive MR was found out on the Co film due to its magnetic anisotropy.
Nitride thin film prepared using Fe_70Co_30 target was a single phase with zinc blende structure. Ferromagnetic Fe_70Co_30 particles started to precipitate in an annealing at 350℃. Negative MR effect appeared with the precipitation of ferromagnetic particles. Positive MR effect was also observed on the annealed films at higher temperature. Crystallinity of the Fe_70Co_30 alloy improved with the annealing temperature.
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Research Products
(5 results)
