| Project/Area Number |
13650364
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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 | Kitakyushu National College of Technology |
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Principal Investigator |
KAJIMA Atsushi Kitakyushu National College of Technology, Department of Electrical and Electronic Engineering, Assistant Professor, 助教授 (70177377)
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| Co-Investigator(Kenkyū-buntansha) |
FUJII Toshitaka Aichi University of Technology, Department of Electronics and Information Engineering, Professor, 工学部, 教授 (90023168)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2001: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Keywords | magnetic oxide thin films / reactive sputtering / dielectric permeability / electric polarization / 酸化物磁性薄膜 / 反応スパッタリング |
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| Research Abstract |
In Bi_2O_3-Fe_2-O_3-PbTiO_3 system thin films prepared by rf-reactive sputtering, ε_r' the real part of dielectric permittivity, was changed by applying a magnetic field H. The Δε_r' vs. H curves of the films subjected to annealing at various temperatures were strongly correlated with their magnetization properties. The maximum relative value of |Δε_r''(H)/ε_r'| reached as much as 1.0%. A ε_r''(H) curve can be reconstructed by a simple model based on uniform magnetization rotation. Next, we measured the temperature dependence of ε_r' and Δε_r'(H)- Both quantities increase rapidly above 50℃, which suggests that softening of the glass network of the dielectric matrix takes place at this temperature to promote the charge displacement giving rise to the dielectric polarization. In addition, we measured the magnetic field dependence of the displacement current Jd(H) to confirm whether the permeability change with magnetic field Δε_r''(H) is intrinsic. It was found that Jd(H) is also subject to change in a similar manner to Δε_r'(H), indicating that the charge displacement assisted by H really occurs. Finally, we observed the dielectric polarization induced by applying a small ac magnetic field at room temperature. This is considered to be a new type of electromagnetic effect. To explain the experimental results, we propose a simple model based on magnetization rotation of ferromagnetic nano-clusters dispersed in a dielectric glassy matrix.
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