| Project/Area Number |
21H01397
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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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| Review Section |
Basic Section 21060:Electron device and electronic equipment-related
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| Research Institution | Keio University |
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Principal Investigator |
KAIJU Hideo 慶應義塾大学, 理工学部(矢上), 教授 (70396323)
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| Co-Investigator(Kenkyū-buntansha) |
介川 裕章 国立研究開発法人物質・材料研究機構, 磁性・スピントロニクス材料研究拠点, 主幹研究員 (30462518)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥17,290,000 (Direct Cost: ¥13,300,000、Indirect Cost: ¥3,990,000)
Fiscal Year 2023: ¥5,460,000 (Direct Cost: ¥4,200,000、Indirect Cost: ¥1,260,000)
Fiscal Year 2022: ¥5,720,000 (Direct Cost: ¥4,400,000、Indirect Cost: ¥1,320,000)
Fiscal Year 2021: ¥6,110,000 (Direct Cost: ¥4,700,000、Indirect Cost: ¥1,410,000)
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| Keywords | 磁気トンネル接合 / キャパシタンス / 交流インピーダンス特性 / 表面・界面物性 / ナノ構造 / スピントロニクス / 磁性薄膜 / トンネル接合 / 誘電体論 |
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| Outline of Research at the Start |
本研究課題では、新規な絶縁体、及び、特異な空間群を有する磁気トンネル接合素子を作製し、従来値を凌駕する巨大な磁気キャパシタンス効果の発現とそのメカニズム解明を目指す。本研究課題の推進は、マイクロ・ナノ構造中の静的なスピン蓄積と交流電場下のスピンダイナミクスに関する新たな学術的知見を提供するとともに、次世代革新的超高性能メモリの実現に向けた重要な設計指針を導くと期待できる。
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| Outline of Final Research Achievements |
Magnetic tunnel junctions (MTJs), which comprise a thin insulator sandwiched between two ferromagnetic layers, exhibit a high tunnel magnetocapacitance (TMC) effect at room temperature. The TMC effect is a phenomenon in which the capacitance changes with the magnetic field in tunneling systems. In this study, we investigate the frequency characteristics and voltage dependence of TMC effect in MgAlO-based MTJs. As a result, we observe a large TMC effect beyond 400% at room temperature in MgAlO-based MTJs. The observed results can be reasonably explained using Debye-Frolich model calculations combined with the Zhang formula, sigmoid function, parabolic approximation, and spin-dependent drift-diffusion theory. Additionally, the calculation predicts a 1500% TMC in the MTJs when 90% spin polarization is achieved. Our results provide a basis for the development of AC/DC spintronic applications.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究成果は、静的なスピン蓄積と交流電場下のスピンダイナミクスに関する新たな学術的知見を提供するとともに、次世代革新的超高性能磁気センサ・メモリの実現に向けた重要な設計指針を導くと期待できる。
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