Novel magnetic circular dichroism in chemically-modified plasmonic nanostructures

2021 Fiscal Year Final Research Report

• Project/Area Number: 18H01808
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 28010:Nanometer-scale chemistry-related
• Research Institution: Mie University
• Principal Investigator: Yao Hiroshi 三重大学, 工学研究科, 教授 (20261282)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 磁気円二色性 / 局在表面プラズモン / 金属ナノ構造体 / 化学合成 / マグネトプラズモン

Outline of Final Research Achievements

This study mainly focused on controlled synthesis and detection/modulation of MCD responses of chemically-modified plasmonic nanostructures as well as on their relevant mechanism elucidations. Consequently, we found that MCD responses of Au-Fe3O4 (gold-magnetite) nanoheterodimers were overwhelmingly dominated by magnetite counterparts, and no LSPR-enhancement was observed, suggesting a reduction of the effective magnetic field to the Au counterparts that can be due to the magnetic shielding by magnetite. In Ag@Au core-shell nanoparticles, the MCD signal with a bisignate response was more distinct than the extinction signal but strong damping was found upon the thin shell formation, which was due to the spectral inhomogeneity. Moreover, in Ag nanoparticles larger than 90 nm, although the higher-mode octupolar plasmonic extinction was unresolved, its MCD clearly showed a very sharp and intense peak, meaning its unique properties with high sensitivity and enhanced spectral resolution.

Free Research Field

ナノ物質化学

Academic Significance and Societal Importance of the Research Achievements

本研究成果の最も重要な学術的意義は、ナノ粒子（ナノ構造体）の化学的合成法の進展とナノフォトニクスの発展が好ましい形で相互作用し、化学屋が化学的な視点でプラズモニクスに積極的に関わる事ができる事を明確に提示する事ができた点にある。リソグラフィーを主体とする物理的研究と対比して、ものづくりを得意とする化学者が様々な合成技術・表面処理技術によって次世代のプラズモニクスを発展・牽引しようとする試みは大いに創造的であり、その社会的意義も大きい。