2005 Fiscal Year Final Research Report Summary
Development and Applications of Nanostructured Soft Magnetic Cores with Extremely Low Loss and Controlled Permeability
| Project/Area Number |
15360170
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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 |
Electronic materials/Electric materials
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| Research Institution | NAGASAKI UNIVERSITY |
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Principal Investigator |
FUKUNAGA Hirotoshi Nagasaki University, Faculty of Engineering, Professor, 工学部, 教授 (10136533)
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| Co-Investigator(Kenkyū-buntansha) |
NAKANO Masaki Nagasaki University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (20274623)
YANAI Takeshi Nagasaki University, Faculty of Engineering, Research Associate, 工学部, 助手 (30404239)
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| Project Period (FY) |
2003 – 2005
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| Keywords | Magnetic loss / Nano-materials / Electronic Materials / Creep / Electronic Devices / Permeability / Magnetism |
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| Research Abstract |
A new material with controllable permeability and extremely low magnetic loss was developed through this research project. The material was prepared by the crystallization of an amorphous Fe-Nb-Si-B ribbon under tensile stress. The crystallization under tensile stress induced magnetic anisotropy perpendicular to the ribbon axis, and resulted in the linear magnetization curve up to magnetic saturation. As the magnitude of the anisotropy was proportional to the stress value, the permeability was controlled easily by changing the magnitude of the applied stress.
The crystallization under tensile stress was achieved by several annealing methods. In the methods, the continuous crystallization of a moving amorphous ribbon by Joule-heating enabled us to prepare a ribbon with controlled permeability under the moving velocity exceeding 200cm/min. As the development of the anisotropy can be completed in an extremely short time less than 1 sec, the continuous crystallization under a faster moving velocity is expected by improving apparatus for crystallization.
Toroidal cores were obtained from a developed ribbon, and their magnetic properties were evaluated at the frequencies up to 2MHz. The prepared cores exhibited superior soft magnetic properties reflecting the magnetic properties of the ribbon, when their diameters were larger than a critical value which was determined from the saturation magnetostriction, Young modulus, and the thickness of the ribbon. Permeability of a core could be controlled at a value of a several hundreds and was constant up to 2MHz. Magnetic loss of the obtained cores was 1/3 of that of a ferrite core. The DC-bias filed applicable to the cores without deterioration of magnetic properties was 3 times as large as that of a ferrite core, which can be attributed to the large saturation magnetization of the developed material.
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