2022 Fiscal Year Annual Research Report
トンネリング電気磁気-誘電効果を発現するナノグラニュラー複相膜の創製
| Project/Area Number |
21K18810
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| Research Institution | Tohoku University |
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Principal Investigator |
曹 洋 東北大学, 学際科学フロンティア研究所, 助教 (50804598)
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| Co-Investigator(Kenkyū-buntansha) |
増本 博 東北大学, 学際科学フロンティア研究所, 教授 (50209459)
小林 伸聖 公益財団法人電磁材料研究所, その他部局等, 研究員 (70205475)
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| Project Period (FY) |
2021-07-09 – 2023-03-31
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| Keywords | dielectric relaxation / granular dielectrics / electric field / electron tunneling / metal-ceramic composites |
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| Outline of Annual Research Achievements |
I have developed novel dielectric nanogranular materials that allow for the tuning of the dielectric relaxation frequency (fr) in the AC transport response using a DC electric field. These materials have the potential to simplify and miniaturize device structures such as RF low pass filters and antennas. The structure consists of magnetic metal nanoparticles dispersed in an insulating matrix. By applying a direct current electric field, it is possible to adjust the fr within a specific frequency range. Interestingly, increasing the electric field initially shifts the fr towards the low-frequency side before moving to the high-frequency side. This observed phenomenon cannot be explained by the conventional symmetric charge tunneling model.
To address this issue, I developed an asymmetric electron tunneling model, which provides an explanation for the observed results. The ability to electrically modulate the relaxation frequency may facilitate the development of innovative tunable frequency filters. I have also theoretically investigated the dielectric properties based on the asymmetric electron tunneling model, taking into account the size difference between granular pairs. This analysis provides valuable insights into the structure-property relationship in disordered granular solids. The findings of this research have been published in Advanced Electronic Materials and have been featured on the Front Cover.
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