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Experimental study for magnetic transport properties in the nonsymmorphic magnets

Research Project

Project/Area Number 21K03445
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
Research InstitutionOsaka University

Principal Investigator

Murakawa Hiroshi  大阪大学, 大学院理学研究科, 助教 (40611744)

Project Period (FY) 2021-04-01 – 2024-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2023: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2022: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2021: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
Keywords巨大磁気抵抗効果 / 磁気ポーラロン / 異方的磁気抵抗効果 / 少数キャリア系半導体 / 層状磁性半導体 / 少数キャリア系 / 磁性半導体 / 電荷密度波 / ノンシンモルフィック
Outline of Research at the Start

本研究では、我々が新たに開発した磁性半導体で観測される巨大な磁気抵抗効果の発現機構の解明に取り組む。様々な磁性元素を用いた半導体単結晶を合成して、磁場方位を精密に制御しながら磁化と電気抵抗率の測定を行うことで、磁気構造や磁気異方性と電気伝導特性との対応関係について明らかにする。また、キャリア密度制御により結晶構造の対称性に基づいた電子物性の顕在化も目指し、新しい機構による磁場に対する巨大応答現象を開拓していく。

Outline of Final Research Achievements

We found that the layered magnetic semiconductor CeTe1.83Sb0.17 exhibits the giant anisotropic magnetoresistance. The electrical resistivity decreases nearly four orders of magnitude in 0.4 T along [100] at 2 K, accompanied by the transition from the antiferromagnetic state to the forced-ferromagnetic state.In contrast, the change of the electrical resistivity is very small in a magnetic field normal to [001].
We prepared the single crystals of CeTe2-xSbx with various carrier density by changing the composition ratio x and compared the magnitude of the magnetoresistance. We observed that the samples with the low carrier density (< 10^18 cm-3) show the large magnetoresistance exceeding two digits. The electrical resistivity approaches a constant value when the magnetization gets close to saturation. In contrast, the change is very tiny in the sample with much higher density. We consider that the giant negative magnetoresistance originates from the mobility change of magnetic polarons.

Academic Significance and Societal Importance of the Research Achievements

磁場中で物質の電気抵抗率が著しく変化する巨大磁気抵抗効果を示す物質は数多く知られているが、磁場方向に依存して何桁も変化する巨大な異方性を示す物質はこれまでにほとんど知られていなかった。本研究では層状構造のCe化合物半導体の電気抵抗率が、ヘリウム温度領域において、永久磁石で到達可能な0.4テスラの磁場方向に依存して4桁程度変化することを発見した。今回観測した前例のない規模での異方性磁気抵抗効果は、希薄な電子密度の磁性半導体で実現する新たな現象であり、その電子状態を理解することにより磁場方向に非常に敏感な検出器等への応用が期待させる。

Report

(4 results)
  • 2023 Annual Research Report   Final Research Report ( PDF )
  • 2022 Research-status Report
  • 2021 Research-status Report
  • Research Products

    (9 results)

All 2023 2022 2021

All Journal Article (4 results) (of which Peer Reviewed: 4 results,  Open Access: 2 results) Presentation (5 results) (of which Int'l Joint Research: 1 results,  Invited: 2 results)

  • [Journal Article] Giant negative magnetoresistance in the layered semiconductor CeTe2-xSbx with variable magnetic polaron density2023

    • Author(s)
      H. Murakawa, Y. Nakaoka, K. Iwase, T. Kida, M. Hagiwara, H. Sakai, N. Hanasaki
    • Journal Title

      Physical Review B

      Volume: 107 Issue: 16 Pages: 165138-165138

    • DOI

      10.1103/physrevb.107.165138

    • Related Report
      2023 Annual Research Report 2022 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Giant anisotropic magnetoresistance at low magnetic fields in a layered semiconductor2022

    • Author(s)
      H. Murakawa, Y. Nakaoka, T. Kida, M. Hagiwara, H. Sakai, N. Hanasaki
    • Journal Title

      Physical Review Materials

      Volume: 6 Issue: 5 Pages: 054604-054604

    • DOI

      10.1103/physrevmaterials.6.054604

    • Related Report
      2022 Research-status Report
    • Peer Reviewed
  • [Journal Article] Anomalous Nernst effect in the nonmagnetic nodal-line semimetal PbTaSe22022

    • Author(s)
      K. Yokoi, H. Murakawa, H. Sakai, N. Hanasaki
    • Journal Title

      Physical Review B

      Volume: 106 Issue: 11 Pages: 115118-115118

    • DOI

      10.1103/physrevb.106.115118

    • Related Report
      2022 Research-status Report
    • Peer Reviewed
  • [Journal Article] Element dependence of local disorder in medium-entropy alloy CrCoNi2021

    • Author(s)
      Hanasaki N.、Oda M.、Niitsu K.、Ehara K.、Murakawa H.、Sakai H.、Nitani H.、Abe H.、Sagayama H.、Uetsuka H.、Karube T.、Inui H.
    • Journal Title

      AIP Advances

      Volume: 11 Issue: 12 Pages: 125216-125216

    • DOI

      10.1063/5.0072766

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Open Access
  • [Presentation] Giant anisotropic magnetoresistance in a layered semiconductor2023

    • Author(s)
      Hiroshi Murakawa
    • Organizer
      Workshop of Research Center for Thermal and Entropic Science - Interplay of Condensed Matter Chemistry and Physics -
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] CeTe2の磁気ポーラロン機構による巨大磁気抵抗効果2022

    • Author(s)
      村川寛、中岡優大、岩瀬圭祐、木田孝則、萩原政幸、酒井英明、花咲徳亮
    • Organizer
      日本物理学会2022年秋季大会
    • Related Report
      2022 Research-status Report
  • [Presentation] 電荷密度波Dy化合物半導体の異方的な磁気抵抗効果2022

    • Author(s)
      村川 寛、他
    • Organizer
      日本物理学会第77回年次大会
    • Related Report
      2021 Research-status Report
  • [Presentation] 電荷密度波磁性半導体CeTe2の異方的な巨大磁気抵抗効果2021

    • Author(s)
      村川 寛、他
    • Organizer
      日本物理学会2021年秋季大会
    • Related Report
      2021 Research-status Report
  • [Presentation] 電荷密度波磁性半導体の巨大磁気抵抗効果2021

    • Author(s)
      村川 寛
    • Organizer
      強磁場オンライン研究会
    • Related Report
      2021 Research-status Report
    • Invited

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Published: 2021-04-28   Modified: 2025-01-30  

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