Development of functionalities with magnetized defects

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K21632
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Physical properties of metals/Metal-base materials; Thin film/Surface and interfacial physical properties
• Research Institution: Kyoto University (2017-2018); Institute of Physical and Chemical Research (2016)
• Principal Investigator: Niitsu Kodai 京都大学, 工学研究科, 助教 (90733890)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 磁性欠陥 / 電子線ホログラフィー / 欠陥強磁性 / 転位 / 機能性材料

Outline of Final Research Achievements

The purpose of this study is the direct real-space detection of magnetism confined in narrow regions such as dislocations, twins and antiphase boundaries. Besides, it covers to develop novel functionalities by utilizing confined magnetism.
Precise determination of magnetic parameters such as magnetic stiffness and magnetic exchange length often requires high quality, large single crystals and well-tailored experiments, which hampers to determine these parameters of various materials. In this study, by using ferromagnetic elements of Fe and Ni, I have developed an easy-to-use method to measure these properties. We can exploit rich information on intrinsic magnetic properties by measuring spin textures within 180-deg magnetic boundaries by means of electron holography.

Free Research Field

材料科学

Academic Significance and Societal Importance of the Research Achievements

交換スティフネスや磁気交換長といった磁気物性パラメータは、良質な単結晶による大規模な実験測定が必要なことが多く、このような試料調製、実験環境が構築できない材料についてこれらの情報を得ることは困難であった。このような困難を克服するため、本研究では単純な強磁性体であるＦｅ，Ｎｉを用い、磁壁内のスピン構造を観察することで交換長を評価できる手法を確立した。これにより、ごく微量・多結晶・ナノ結晶の磁性体であっても１８０磁壁内部のスピン構造を電子線ホログラフィーで可視化することにより、交換長をはじめとする磁気物性の評価が可能となった。