| Project/Area Number |
02555060
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
電子材料工学
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| Research Institution | Kyushu Institute of Technology |
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Principal Investigator |
OHKOSHI Masatoshi Kyushu Institute of Technology, Faculty of Computer Science, Associate Professor, 情報工学部, 助教授 (90112177)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Naohiro Kyushu Institute of Technology, Faculty of Computer Science, Assistant Professor, 情報工学部, 助手 (30230981)
MAKI Kouichiro Sumitomo Metals & Mining, Co. Central laboratory, Chief researcher, 中央研究所, 主任研究員
TSUSHIMA Kuniro Kyushu Institute of Technology, Faculty of Computer Science, Professor, 情報工学部, 教授 (50217296)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥17,500,000 (Direct Cost: ¥17,500,000)
Fiscal Year 1991: ¥5,100,000 (Direct Cost: ¥5,100,000)
Fiscal Year 1990: ¥12,400,000 (Direct Cost: ¥12,400,000)
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| Keywords | magneto-optic memory / magnetic thin film / permanent magnet / high speed camera / magnetic domain / domain wall / coercivity |
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| Research Abstract |
In order to improve the magneto-optical disc and Nd-Fe-B magnet it is important to know the mechanism of coercivity by investigating the growth mechanism of Nd-Fe-B film and dynamic magnetization reversal process, which depends on the microstructure. Nd-Fe-B film and Fe film were prepared by RF magnetron sputtering. Growth process in the initial stage was studied by RHEED and electrical resistivity in situ.
The resistivity decrease exponentially against film thickness until 30 A due to the two dimensional growth of the nuclei. The resistivity decrease further until a critical thickness of 50 A by developing inland, and forms continuous film. The critical thickness is about 50 A below 150 C of the substrate temperature. The resistivity is high for the film deposited at high substrate temperature because of rough surface, which is Associated with an increased size of inland at the initial growth when the substrate temperature is above 200 C, and the critical thickness increase more than 100 A for high substrate temperature. Grain size and crystal orientation depend on the concentration of Nd and B. Magnetic properties and magneto-optical effects of Nd-Fe-B films were studied. Microstructure, magnetic anisotropy, and coercivity change at a certain composition region.
Fe films were deposited further by excimer laser ablation method. The crystallinity of the Fe film prepared at high repetition rate is high and shows high coercivity, which is associated with a formation of the Fe-N phase.
Domain wall movement including domain nucleation and wall propergation was studied by high speed framing streak camera. Three stable states of bubble domain with different diameter were found, after chopping the stripe domain by 10 nsec pulse field. Bloch line was observed successfully, and the velocity exceeds 1 km/sec which depends on the length of the Bloch line.
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