Study of Spin States of Organic Conductors Studied by Magnetic Circular Dichroism Spectroscopy Using Infrared Synchrotron Radiation

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K12639
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 80040:Quantum beam science-related
• Research Institution: Japan Synchrotron Radiation Research Institute
• Principal Investigator: Ikemoto Yuka 公益財団法人高輝度光科学研究センター, 分光推進室, 主幹研究員 (70344398)
• Co-Investigator(Kenkyū-buntansha): 佐々木 孝彦 東北大学, 金属材料研究所, 教授 (20241565) ; 井口 敏 東北大学, 金属材料研究所, 准教授 (50431789)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 赤外線領域放射光 / 顕微分光 / 磁気光学応答 / 磁気円二色性 / 分生性導体

Outline of Final Research Achievements

In this study, an infrared micromagnetic circular dichroism system was developed to discuss the relationship between spin states and energy bands through dichroism spectra of molecular conductor materials and other materials. Experiments were performed at the magneto-optical station of the infrared material beamline BL43IR at SPring-8, which is capable of low-temperature microscopic measurements under a magnetic field of up to ±14 T. In order to observe weak signal due to magneto-optical effects, we built the circular dichroism system by introducing a photoelastic modulator (PEM) into the station, which covers 5000-800 cm-1 wavenumber region. Clear results were obtained with CdSb, which has been reported to have a large dichroic signal in the infrared region. Significant changes were also observed in molecular conductors, which exhibit various properties due to strong electronic correlations.

Free Research Field

赤外線放射光、赤外分光

Academic Significance and Societal Importance of the Research Achievements

本研究では、赤外線領域の磁気光学効果の信号を測定する装置開発を行い、これを利用して、電子間の強い相互作用により磁気秩序状態を示すCeSbと分子伝導体の測定を行なった。これらの物質は、赤外線領域に磁性発現に関わる電子のバンド間遷移を持ち、スピン状態や磁性発現の機構の解明が可能となる。また、分子伝導体の測定にあたっては、異方性を考慮した測定・解析手法を開拓したため、装置は多くの固体試料に適応できる。