Updated on 2025/06/09

Information

 

写真a

 
IIMORI RIKU
 
Organization
Faculty of Science Department of Physics Assistant Professor
School of Sciences Department of Physics(Concurrent)
Graduate School of Sciences Department of Physics(Concurrent)
Title
Assistant Professor
Contact information
メールアドレス
Profile
Interface between different materials exhibits unique electronic and magnetic states due to broken spatial inversion symmetry and reduced dimensionality. To investigate these novel properties, I employ spin current control techniques based on microfabrication, as well as interface tuning methods using high-pressure technology. I also explore the potential for developing novel devices based on these interfacial phenomena.
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Research Areas

  • Nanotechnology/Materials / Applied physical properties

  • Natural Science / Magnetism, superconductivity and strongly correlated systems

Degree

  • Doctor of Science

Awards

  • Outstanding poster award, "Pressure effect on unidirectional magnetoresistance in heavy metal/ferromagnetic bilayer", The 7th International Symposium on Frontiers in Materials Science

Papers

  • Substantial enhancement of perpendicular magnetic anisotropy in van der Waals ferromagnetic Fe<sub>3</sub>GaTe<sub>2</sub> film due to pressure application

    Iimori, R; Hu, SJ; Mitsuda, A; Kimura, T

    COMMUNICATIONS MATERIALS   5 ( 1 )   2024.10   eISSN:2662-4443

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    Publisher:Communications Materials  

    Van der Waals (vdW) two-dimensional (2D) materials have unleashed unprecedented opportunities to probe emerging physics that could be potential candidates for various functional applications. In particular, vdW 2D magnetic materials exhibit significant potential for advanced spintronic devices. Recently, Fe3GaTe2 has been discovered to possess the room-temperature ferromagnetic property with an intrinsic perpendicular magnetic anisotropy (PMA). Furthermore, considerably large anomalous Hall and Nernst angles have been reported recently. These groundbreaking findings pave the way for significant advances in high density random-access memory as well as energy harvesting devices based on spin conversion. Enhancements in the PMA and Curie temperature contribute to improved performance with reliable operation in a wide temperature range above room temperature. Moreover, the exploration of giant anomalous Hall and Nernst angles is a crucial factor for the efficient operation of spintronic devices. In this study, we demonstrate that the application of pressure to the Fe3GaTe2 2D ferromagnetic film strengthens the interlayer coupling, resulting in an improved PMA property. In addition, the application of pressure has been found to significantly increase the anomalous Hall angle. Our findings suggest that the application of pressure effectively controls the vdW interlayer coupling, thereby manipulating the ferromagnetic and spin-conversion properties of the 2D materials.

    DOI: 10.1038/s43246-024-00665-3

    Web of Science

    Scopus

  • Resistivity Measurements in Palladium Hydride Film Prepared by Low-Temperature Hydrogen Absorption Method

    Kato, R; Yoshida, T; Iimori, R; Zizhou, T; Shiga, M; Inagaki, Y; Kimura, T; Kawae, T

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   93 ( 2 )   2024.2   ISSN:0031-9015

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    Publisher:Journal of the Physical Society of Japan  

    We investigated the superconducting properties of a palladium hydride (PdHx; x = H=Pd) film with a thickness of ∼100 nm prepared by a low-temperature hydrogen (H) absorption method. H atoms were loaded to a Pd film in H2 gas pressure of ∼0.25 MPa at temperatures of T = 180 and 150 K. At T = 180 K, after the resistivity variation due to H absorption was almost stopped, the PdHx film was cooled rapidly to low temperatures for the resistivity measurements. A superconducting transition was observed at Tc ∼ 1.1 K, where the transition width is smaller than 0.1 K. This indicates that a high-quality sample with a sharp transition can be obtained by providing sufficient time for H absorption. At T = 150 K, although the resistivity variation remained, the film was cooled. The transition temperature Tc increased to ∼2.1 K, whereas the transition width increased owing to the inhomogeneity of the H concentration in the film. Curiously, regardless of the H homogeneity, there remained a similar T-dependent residual resistivity in both films prepared at T = 180 and 150 K after the superconducting transition. This implies that the observed residual resistivity is essential for the future of the system, although its origin is not clear.

    DOI: 10.7566/JPSJ.93.024703

    Web of Science

    Scopus

  • Experimental and Theoretical Evaluation for Pressure Effects on Spin Hall Effect in Pt

    Iimori, R; Obinata, S; Yamazaki, T; Mitsuda, A; Kimura, T

    IEEE TRANSACTIONS ON MAGNETICS   59 ( 11 )   2023.11   ISSN:0018-9464 eISSN:1941-0069

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    Publisher:IEEE Transactions on Magnetics  

    We have experimentally and theoretically investigated the influence of pressure on the spin Hall effect (SHE) for the Pt. The experimental results using a laterally configured Pt/CoFeB hybrid nanostructure suggest that the spin Hall angle for the Pt is almost constant under pressure up to 2 GPa. The theoretical study based on the first-principles calculation found the spin Hall conductivity for the Pt shows a 10% reduction due to the pressure application of 75 GPa, supporting the experimental results. These results imply that the enhanced spin Hall signal in the dynamical spin injection due to the pressure application is caused by the enhancement of the interfacial spin mixing conductance.

    DOI: 10.1109/TMAG.2023.3283467

    Web of Science

    Scopus

  • Pressure-induced enhancement of spin-charge conversion efficiency in CoFeB/Pt bilayer

    Iimori, R; Obinata, S; Mitsuda, A; Kimura, T

    APPLIED PHYSICS EXPRESS   15 ( 3 )   2022.3   ISSN:1882-0778 eISSN:1882-0786

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    Publisher:Applied Physics Express  

    We experimentally investigate the influence of the pressure on the spin-charge conversion efficiency in a CoFeB/Pt bilayer system by using a specially designed pressure-cell setup. The dc voltage spectra under the dynamical spin injection is found to show the systematic increase with increasing pressure. These modifications can be understood by the enhancement of the spin-charge conversion efficiency due to the modulation of the spin-orbit interaction and/or the exchange interaction at the interface. The present demonstration indicates that the pressure provides a tunable functionality for the physical constants in spintronic devices.

    DOI: 10.35848/1882-0786/ac5501

    Web of Science

    Scopus

Professional Memberships

  • The Magnetics Society of Japan

  • The Japan Society of Applied Physics

  • The Physical Society of Japan

Research Projects

  • 圧力印加によるチューナブルな界面電子状態の実現と新奇スピンデバイスへの応用

    Grant number:23KJ1701  2023.4 - 2025.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for JSPS Fellows

    飯森 陸

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    Grant type:Scientific research funding

    異種物質界面におけるスピン軌道相互作用に起因した電流とスピン流の相互変換現象は高効率な磁化反転などへの応用が期待されている一方で、界面の原子間距離に極めて敏感であり、圧力印加により大きな変化を誘引できる可能性がある。そこで、申請者が確立した高圧力下におけるスピン流物性の評価手法を界面ラシュバ効果によるスピン流-電流変換現象に適用することで、変換効率の飛躍的向上のための設計指針の確立を目指す。更にその知見をもとに、界面圧力による巨大スピン流の生成や、磁気スキルミオンの生成・消滅などの革新的な界面スピン物性の圧力制御の実現を目指す。

    CiNii Research

Class subject

  • 自然科学総合実験

    2025.10 - Present   Second semester

  • 物理学総合実験

    2025.4 - Present