Observation of voltage-induced large magnetocapacitance effect in magnetic tunnel junctions

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H01485
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 21060:Electron device and electronic equipment-related
• Research Institution: Keio University (2019-2020); Hokkaido University (2018)
• Principal Investigator: KAIJU Hideo 慶應義塾大学, 理工学部(矢上), 准教授 (70396323)
• Co-Investigator(Kenkyū-buntansha): 西井 準治 北海道大学, 電子科学研究所, 教授 (60357697) ; 長浜 太郎 北海道大学, 工学研究院, 准教授 (20357651)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: スピントロニクス / 磁性薄膜 / 誘電体 / 交流インピーダンス特性 / 電気容量

Outline of Final Research Achievements

Magnetocapacitance (MC) effect has attracted much attention due to their potential applications as highly-sensitive magnetic sensors, high-frequency devices and energy storage materials. The MC effect has been observed in multiferroic materials, spintronic devices and magnetic supercapacitors. Here we focus on magnetic tunnel junctions (MTJs) in spintronic devices, and we report a new phenomenon, in which the tunneling magnetocapacitance (TMC) increases with biasing voltage in MgO-based MTJs. We have observed a maximum TMC value of beyond 300%, which is the largest voltage-induced TMC effect ever reported for MTJs. We have found excellent agreement between theory and experiment using extended Debye-Frohlich model. Based on our calculation, we predict that the TMC ratio could reach 1000% in MTJs. Our work has provided a new understanding on AC spin-dependent transports in spintronic devices, and the results reported here may open a novel pathway for spintronics applications.

Free Research Field

応用物理

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。