2018 Fiscal Year Final Research Report

Induction of magnetic function on two-dimensional metal thin film based on quantum well structure and its application

Research Project

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Project/Area Number	15H01998
Research Category	Grant-in-Aid for Scientific Research (A)
Allocation Type	Single-year Grants
Section	一般
Research Field	Nanostructural physics
Research Institution	Keio University
Principal Investigator	SATO Tetsuya 慶應義塾大学, 理工学部(矢上), 教授 (20162448)
Co-Investigator(Kenkyū-buntansha)	沢田正博広島大学, 放射光科学研究センター, 准教授 (00335697) 島田賢也広島大学, 放射光科学研究センター, 教授 (10284225) 谷山智康名古屋大学, 理学研究科, 教授 (10302960) 神原陽一慶應義塾大学, 理工学部(矢上), 准教授 (50524055) 影島博之島根大学, 学術研究院理工学系, 教授 (70374072)
Project Period (FY)	2015-04-01 – 2019-03-31
Keywords	量子井戸 / 配向超薄膜 / Pd薄膜 / Pt薄膜 / 強磁性発現 / 電場による磁化制御 / 歪みによる磁化制御 / 磁気異方性制御
Outline of Final Research Achievements	Magnetic properties of (100) Pd and Pt ultra thin films were discussed based on experiments and electronic structure calculation. Both the films showed ferromagnetism depending on film thickness through the formation of quantum well states and the mechanism were elucidated. The external methods, such as the change in Schottky barrier by electric field application between Pd thin film and semiconductor substrate and the strain application to the Pd thin film on ferroelectric substrate, modulated the magnetic properties of Pd. The modulation of magnetic anisotropy of Fe thin film deposited on Pd film was observed by modifying the electronic structure in Fe film through the changed in quantum well state in Pd depending on Pd film thickness. By modulating the quantum well, it was revealed that ferromagnetism can be artificially imparted to nonmagnetic materials, and its magnetic state and the magnetism of adjacent metals can be externally controlled.
Free Research Field	磁気工学
Academic Significance and Societal Importance of the Research Achievements	磁気記録などでの低消費電力化を目指すために外場（電場、歪み等）による磁性制御が希求され関連した多くの報告があるが、その基本原理が十分には明確にされてない。本研究では、Pd、Ptなどの交換増大された金属薄膜に形成される量子井戸構造に注目し、非磁性金属への磁気機能の付加とその制御と磁化配向の操作を実現するための学理の構築を目指した。量子井戸状態を電場・歪み等により操作して、 (100)Pd、Pt薄膜への強磁性付加とその磁化制御、これらの膜に近接した強磁性Fe薄膜の磁気異方性制御を実現した。これより情報機器やシステム構成機器の超低消費電力化、高機能化などの革新的な磁気応用技術への展開が現実となる。