Details of the Researcher

PHOTO

Takeshi Seki
Section
Institute for Materials Research
Job title
Professor
Degree

  • 博士（工学）（東北大学）

  • 修士（工学）（東北大学）

Committee Memberships 10

  • 応用物理学会スピントロニクス研究会　幹事

    2021/01 - Present

  • 電気学会　ナノスケール磁性体を用いた機能性材料開発調査専門員会委員

    2019/07 - Present

  • 日本金属学会　講演大会委員会委員

    2019/04 - Present

  • Program Committee member, International Colloquium on Magnetic Thin Films and Surfaces (ICMFS) 2022

    2019/08 - 2022/07

  • スピントロニクス研究会　企画幹事

    2019/01 - 2020/12

  • The 65th Annual Conference on Magnetism and Magnetic Materials (MMM 2020)　Program Committee member

    2019/10 - 2020/11

  • 日本磁気学会　企画委員会

    2015/06 - 2019/05

  • 応用物理学会　ロードマップ委員

    2013/01 - 2016/12

  • スピントロニクス研究会　企画幹事

    2013/01 - 2014/12

  • 日本物理学会　領域３運営委員

    2011/05 - 2012/04

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Professional Memberships 4

  • 日本物理学会

  • 日本金属学会

  • 日本磁気学会

  • 応用物理学会

Research Interests 4

  • Nanostructure

  • Magnetic thin film

  • Spintronics

  • Magnetic Materials

Research Areas 1

  • Nanotechnology/Materials / Structural and functional materials /

Awards 13

  1. 第80回 日本金属学会功績賞

    2022/03　日本金属学会

  2. 2019年度 船井学術賞

    2020/02　船井情報科学振興財団

  3. 第40回本多記念研究奨励賞

    2019/05　本多記念会

  4. 平成31年度科学技術分野の文部科学大臣表彰・若手科学者賞

    2019/04　文部科学省

  5. 第16回 インテリジェント・コスモス奨励賞

    2017/05/15　インテリジェント・コスモス学術振興財団

  6. 日本磁気学会 2016年 優秀研究賞

    2016/09/07　日本磁気学会

  7. 日本金属学会 第22回奨励賞

    2012/09/17　日本金属学会

  8. 第52回原田研究奨励賞

    2012/07/06　本多記念会

  9. 第16回青葉工学研究奨励賞

    2010/12/10　財団法人青葉工学振興会

  10. 平成18年度トーキン科学技術振興財団研究奨励賞

    2007/03　トーキン科学技術振興財団

  11. 第7回及川研究奨励賞

    2003/11　青葉工学振興会

  12. 第4回TBOC技術アイディア審査員奨励賞

    2003/09　TBOC

  13. 第27回応用磁気学会学術講演会優秀講演賞

    2003/09　応用磁気学会

Show all ︎Show 5

Papers 167

  1. Stoichiometry control and epitaxial growth of AgCrSe2 thin films by pulsed-laser deposition Peer-reviewed

    Yusuke Tajima, Kenshin Inamura, Sebun Masaki, Takumi Yamazaki, Takeshi Seki, Kazutaka Kudo, Jobu Matsuno, Junichi Shiogai

    APL Materials　13　(6)　061117-1-061117-7　2025/06/01

    Publisher: AIP Publishing

    DOI： 10.1063/5.0273060 　

    eISSN： 2166-532X

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    We report on epitaxial growth in thin-film synthesis of a polar magnetic semiconductor, AgCrSe2, on a lattice-matched yttria-stabilized zirconia (111) substrate by pulsed-layer deposition (PLD). By using an Ag-rich PLD target to compensate for Ag deficiency in thin films, the nucleation of impurity phases is suppressed, resulting in the c-axis-oriented and single-phase AgCrSe2 thin film. Structural analysis using x-ray diffraction and cross-sectional scanning transmission electron microscopy reveals epitaxial growth with the presence of both twisted and polar domains. Optical absorbance spectrum and magnetization measurements show an absorption edge at around 0.84 eV and a magnetic transition temperature at 41 K, respectively. These values are consistent with the reported values of direct bandgap and Néel temperature of bulk AgCrSe2, reflecting a single-phase and stoichiometric feature of the obtained film. Our demonstration of epitaxial thin-film growth of AgCrSe2 serves as a bedrock for exploration of its potential thermoelectric and spintronic functionalities at surfaces or heterointerfaces.

  2. Suppression of ferromagnetism in rippled La2/3Sr1/3MnO3 membrane with process-induced strain prepared by epitaxial lift-off technique Peer-reviewed

    Kota Kanda, Ryuji Atsumi, Takamasa Usami, Takumi Yamazaki, Kohei Ueda, Takeshi Seki, Shigeki Miyasaka, Jobu Matsuno, Junichi Shiogai

    APL Materials　13　(4)　041117-1-041117-7　2025/04/01

    Publisher: AIP Publishing

    DOI： 10.1063/5.0263925 　

    eISSN： 2166-532X

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    Transition metal oxides are a platform for exploring strain-engineered intriguing physical properties and developing spintronic or flexible electronic functionalities owing to the strong coupling of spin, charge, and lattice degrees of freedom. In this study, we exemplify the strain-engineered magnetism of La2/3Sr1/3MnO3 in freestanding and rippled membrane forms without and with process-induced strain, respectively, prepared by the epitaxial lift-off technique. We find that the deposition of the Pt/Ti stressor suppresses the crack formation in the lift-off process and induces a ripple structure in the La2/3Sr1/3MnO3 membrane. Laser micrograph and Raman spectroscopy show a ripple period of about 30 μm and a height of a few μm, where alternating convex and concave structures are subjected to a tensile strain of 0.6% and a compressive strain of 0.5%, respectively. While the freestanding La2/3Sr1/3MnO3 membrane exhibits room-temperature ferromagnetism, the macroscopic magnetic transition temperature (TC) of the rippled membrane is reduced by as much as 27%. Temperature-variable Kerr microscopy observation in the rippled membrane reveals that the spatial variation of TC is ∼4% of the macroscopic TC, which coincides with the local strains at convex and concave structures. The large reduction of macroscopic TC in the rippled membrane may be ascribed to the lattice disorders due to the strain gradient. Our demonstration of tuning ferromagnetism by the ripple structure validates the high potential of the process-induced strain in the epitaxial lift-off technique and paves the way for strain-mediated emerging physical properties in various transition metal oxides.

  3. Giant tunability of magnetoelasticity in Fe4N system as a platform to unveil correlation between magnetostriction and magnetic damping Peer-reviewed

    Keita Ito, Ivan Kurniawan, Yusuke Shimada, Yoshio Miura, Yasushi Endo, Takeshi Seki

    Communications Materials　6　(1)　53-1-53-8　2025/03/26

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s43246-025-00784-5 　

    eISSN： 2662-4443

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    Abstract Flexible spintronics has opened avenues to promising devices and applications in the field of wearable electronics. For miniaturized strain sensors exploiting the spintronic function, the magnetoelasticity linking magnetism and lattice distortion is a vital property. Here we report the demonstration that the magnetoelastic properties of Fe4N can be significantly varied by partially replacing Fe with Co or Mn. The high quality Fe4N film exhibits large negative magnetostriction along the [100] direction (λ 100) of −121 ppm while Fe2.3Co1.7N shows λ 100 of + 46 ppm. The strong correlation between λ 100 and magnetic damping (α) is found. The enhanced extrinsic term of α is attributable to the large two magnon scattering coming from the large magnetostriction. In addition, the density of states at the Fermi level plays a primal role to determine both λ 100 and the intrinsic term of α. Thanks to the giant tunability and the bipolarity of magnetoelasticity, magnetic nitrides are candidate materials for high-sensitive spintronic strain sensors.

  4. Antisymmetric interlayer exchange coupling spontaneously built in synthetic antiferromagnetic structures using film growth Peer-reviewed

    Takeshi Seki, Hiroto Masuda, Varun K Kushwaha, Takumi Yamazaki, Keita Ito

    Journal of Physics D: Applied Physics　58　(17)　175002-1-175002-10　2025/03/18

    Publisher: IOP Publishing

    DOI： 10.1088/1361-6463/adbd4f 　

    ISSN： 0022-3727

    eISSN： 1361-6463

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    Abstract The antisymmetric-type long-range exchange interactions between two ferromagnetic layers through a nonmagnetic layer, called antisymmetric interlayer exchange coupling (AIEC), have recently been discovered and attracted much attention. This paper reports that AIEC is naturally built in synthetic antiferromagnets (SyAFs) depending on the thin-film growth conditions. For SyAFs comprising Pt/Co/Ir/Co/Pt layers, two kinds of film growth parameters are examined: the effects of epitaxial growth and oblique incident of sputter-deposition. The present results indicate that spatial fluctuations in thicknesses are one of the major sources inducing AIEC, whereas epitaxial growth, which leads to sharp interfaces and uniformity in layer thicknesses, effectively suppresses unexpected AIEC. In addition, the oblique sputter deposition provides large AIEC and anisotropic distribution of AIEC direction in the case of textured films. The findings in this study provide key factors for designing AIEC and are useful for developing emerging computing technologies with artificial three-dimensional topological magnetic structures.

  5. Current-Induced Sliding Motion in a Helimagnet MnAu2 Peer-reviewed

    Yuta Kimoto, Hidetoshi Masuda, Takeshi Seki, Yoichi Nii, Jun-ichiro Ohe, Yusuke Nambu, Yoshinori Onose

    Phys. Rev. Lett.　134　056702-1-056702-6　2025/02/05

    DOI： 10.1103/PhysRevLett.134.056702 　

  6. Proof‐of‐Concept for Selective Magnetization Switching for Microfabricated Exchange‐Spring Magnets by Spin Wave Excitation Peer-reviewed

    V. K. Kushwaha, T. Yamazaki, T. Seki

    Advanced Physics Research　4　2400160-1-2400160-10　2025/01

    Publisher: Wiley

    DOI： 10.1002/apxr.202400160 　

    ISSN： 2751-1200

    eISSN： 2751-1200

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    Abstract This paper presents a proof‐of‐concept for selective magnetization switching in microfabricated elements with L10‐FePt/Ni81Fe19 (permalloy; Py) exchange‐coupled bilayers, known as exchange‐spring magnets, by exciting spin wave dynamics. Although the resonance frequency of the perpendicular standing spin wave mode definitely can be tuned by varying the Py layer thickness or the aspect ratio of the element, considering the requirements of selective magnetization switching, it is found that the frequency tuning by varying the aspect ratio is suitable. The spin wave‐assisted magnetization switching (SWAS) experiments for the different aspect ratios reveal the condition for the switching field reduction for each aspect ratio. Thanks to the different resonance frequencies between the different aspect ratios, the selective nature of SWAS method is experimentally demonstrated. The findings involve the contribution of higher‐order spin wave dynamics, and emphasize the significance of adjusting the aspect ratio of elements to realize selective magnetization switching, offering potential applications in multilevel recording media.

  7. Magnetoelastic coupling for Fe–Ga thin films epitaxially grown on different substrates Peer-reviewed

    Hao Ding, Keita Ito, Yasushi Endo, Koki Takanashi, Takeshi Seki

    Journal of Physics D: Applied Physics　57　(38)　385002-385002　2024/06/28

    Publisher: IOP Publishing

    DOI： 10.1088/1361-6463/ad58f0 　

    ISSN： 0022-3727

    eISSN： 1361-6463

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    Abstract This paper reports the systematic study on the structure, magnetic properties and magnetoelastic properties for the Fe100−x Ga x (001) thin films epitaxially grown on the different substrates of GaAs(001) and MgO(001) using the sputtering technique. The alloy composition dependence of effective magnetoelastic coupling coefficient B eff along the FeGa [110] direction indicated that the largest magnetoelastic coupling was obtained for the Fe–Ga layer with x = 30 grown on the MgO substrate, which was evaluated to be B eff = − 9.4 × 107 erg cm−3. Considering the results of structural analysis and magnetization measurement, the different crystallite sizes depending on the kind of substrate may give rise to the different magnetoelastic coupling strengths between the Fe–Ga layers on the MgO and the GaAs. The magnetostriction along the Fe–Ga [111] direction λ 111 was also estimated with the assumption of plausible elastic property of Fe–Ga, and showed the values comparable to the reported value of bulk Fe–Ga. This means the large magnetostriction can be obtained even for the Fe–Ga thin films epitaxially grown not only on the GaAs(001) but also on the MgO(001). The findings in this work will give a guideline for designing spintronic applications with a Fe–Ga layer exhibiting a large magnetoelastic coupling.

  8. High‐Throughput Optimization of Magnetoresistance Materials Based on Lock‐In Thermography Peer-reviewed

    Rajkumar Modak, Takamasa Hirai, Yuya Sakuraba, Seiji Mitani, Koichi Oyanagi, Takumi Yamazaki, Takeshi Seki, Ken‐ichi Uchida

    Advanced Physics Research　3　2400021-1-2400021-8　2024/05/24

    Publisher: Wiley

    DOI： 10.1002/apxr.202400021 　

    ISSN： 2751-1200

    eISSN： 2751-1200

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    Abstract With the giant magnetoresistance (GMR) effect serving as a vital component in modern spintronic technologies, researchers are dedicating significant efforts to improve the performance of GMR devices through material exploration and design optimization. However, traditional GMR measurement approaches are inefficient for comprehensive material and device optimization. This study proposes a high‐throughput current‐in‐plane GMR measurement technique based on thermal imaging of Joule heating utilizing lock‐in thermography (LIT). This LIT‐based technique is advantageous for efficiently evaluating films with varying compositions and thickness gradients, which is crucial for ongoing material exploration and design optimization to enhance the GMR ratio. First, it is demonstrated that using CoFe/Cu multilayers, the simple Joule heating measurement based on LIT enables quantitative estimation of the GMR ratio. Then, to confirm the usefulness of the proposed method in high‐throughput material screening, a case study is shown to investigate the GMR of CoCu‐based granular films with a composition gradient. These techniques allow to determine the optimum composition with maximum GMR ratio using the single composition‐gradient film and reveal Co22Cu78 as the optimal composition, yielding the largest GMR ratio among the reported polycrystalline CoCu‐based granular films. This demonstration accelerates the material and structural optimization of GMR devices.

  9. Spin caloritronics in metallic superlattices Invited Peer-reviewed

    T Seki, K Uchida, K Takanashi

    Journal of Physics: Condensed Matter　36　(33)　333001-1-333001-11　2024/05/20

    Publisher: IOP Publishing

    DOI： 10.1088/1361-648x/ad4761 　

    ISSN： 0953-8984

    eISSN： 1361-648X

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    Abstract Spin caloritronics, a research field studying on the interconversion between a charge current () and a heat current () mediated by a spin current () and/or magnetization (M), has attracted much attention not only for academic interest but also for practical applications. Newly discovered spin-caloritronic phenomena such as the spin Seebeck effect (SSE) have stimulated the renewed interest in the thermoelectric phenomena of a magnet, which have been known for a long time, e.g. the anomalous Nernst effect (ANE). These spin-caloritronic phenomena involving the SSE and the ANE have provided with a new direction for thermoelectric conversion exploiting and/or M. Importantly, the symmetry of ANE allows the thermoelectric conversion in the transverse configuration between and . Although the transverse configuration is totally different from the conventional longitudinal configuration based on the Seebeck effect and has many advantages, we are still facing several issues that need to be solved before developing practical applications. The primal issue is the improvement of conversion efficiency. In the case of ANE-based applications, a material with a large anomalous Nernst coefficient () is the key for solving the issue. This review article introduces the increase of can be achieved by forming superlattice structures, which has been demonstrated for several kinds of materials combinations. The overall picture of studies on spin caloritronics is first surveyed. Then, we mention the pioneering work on the transverse thermoelectric conversion in superlattice structures, which was performed using Fe-based metallic superlattices, and show the recent studies for the Ni-based metallic superlattices and the ordered alloy-based metallic superlattices.

  10. Zero-magnetic-field operation of ordinary-Nernst-effect-based transverse thermoelectric module using embedded permanent magnets Peer-reviewed

    Masayuki Murata, Takamasa Hirai, Takeshi Seki, Ken-ichi Uchida

    Applied Physics Letters　124　(19)　193901-1-193901-7　2024/05/06

    Publisher: AIP Publishing

    DOI： 10.1063/5.0202818 　

    ISSN： 0003-6951

    eISSN： 1077-3118

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    The ordinary Nernst effect enables large transverse thermoelectric conversion in semimetals, but its operation requires the application of an external magnetic field. In this study, we propose a transverse thermoelectric conversion module structure with embedded permanent magnets and demonstrate thermoelectric power generation by the ordinary Nernst effect in the absence of an external magnetic field. In our prototype module comprising alternately stacked Bi88Sb12 slabs and Nd2Fe14B-type permanent magnets, the stray magnetic field generated by the remanent magnetization of the Nd2Fe14B-type magnets is always applied to the Bi88Sb12 slabs, and a power of 13.2 μW is generated due to the ordinary Nernst effect at a temperature difference of 120 K and average temperature of 260 K at zero external field. This thermoelectric module concept will contribute to the further development of transverse thermoelectric conversion technologies utilizing permanent magnets.

  11. Non-coplanar spin structure in a metallic thin film of triangular lattice antiferromagnet CrSe Peer-reviewed

    Yusuke Tajima, Junichi Shiogai, Kohei Ueda, Hirotake Suzaki, Kensuke Takaki, Takeshi Seki, Kazutaka Kudo, Jobu Matsuno

    APL Materials　12　(4)　041112-1-041112-8　2024/04/01

    Publisher: AIP Publishing

    DOI： 10.1063/5.0201786 　

    eISSN： 2166-532X

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    An antiferromagnetic metal with a two-dimensional triangular network offers a unique playground of intriguing magneto-transport properties and functionalities stemming from the interplay between conducting electrons and intricate magnetic phases. A NiAs-type CrSe is one of the candidates owing to alternate stackings of Cr and Se triangular atomic networks in its crystal structure. While the fabrication of CrSe thin films is indispensable to develop functional devices, studies on its thin-film properties have been limited to date due to the lack of metallic samples. Here, we report on the realization of metallic conductivities of CrSe thin films, which allows us to investigate their intrinsic magneto-transport properties. The metallic sample exhibits a co-occurrence of weak ferromagnetism with perpendicular magnetic anisotropy and antiferromagnetic behavior, indicating the presence of non-coplanar spin structures. In addition, control of the polarity and tilting angle of the non-coplanar spin structure is accomplished by a sign of cooling magnetic fields. The observed non-coplanar spin structure, which can be a source of emergent magnetic field acting on the conducting electrons, highlights the high potential of the triangular lattice antiferromagnet and provides a unique platform for functional thin-film devices composed of NiAs-type derivative Cr chalcogenides and pnictides.

  12. Room temperature chirality switching and detection in a helimagnetic MnAu2 thin film Peer-reviewed

    Hidetoshi Masuda, Takeshi Seki, Jun-ichiro Ohe, Yoichi Nii, Hiroto Masuda, Koki Takanashi, Yoshinori Onose

    Nature Communications　15　(1)　1999-1-1999-8　2024/03/07

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41467-024-46326-4 　

    eISSN： 2041-1723

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    Abstract Helimagnetic structures, in which the magnetic moments are spirally ordered, host an internal degree of freedom called chirality corresponding to the handedness of the helix. The chirality seems quite robust against disturbances and is therefore promising for next-generation magnetic memory. While the chirality control was recently achieved by the magnetic field sweep with the application of an electric current at low temperature in a conducting helimagnet, problems such as low working temperature and cumbersome control and detection methods have to be solved in practical applications. Here we show chirality switching by electric current pulses at room temperature in a thin-film MnAu2 helimagnetic conductor. Moreover, we have succeeded in detecting the chirality at zero magnetic fields by means of simple transverse resistance measurement utilizing the spin Berry phase in a bilayer device composed of MnAu2 and a spin Hall material Pt. These results may pave the way to helimagnet-based spintronics.

  13. Quantitative measurement of figure of merit for transverse thermoelectric conversion in Fe/Pt metallic multilayers Peer-reviewed

    Takumi Yamazaki, Takamasa Hirai, Takashi Yagi, Yuichiro Yamashita, Ken-ichi Uchida, Takeshi Seki, Koki Takanashi

    Physical Review Applied　21　(2)　024039-1-024039-11　2024/02/21

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevapplied.21.024039 　

    eISSN： 2331-7019

  14. Bipolarity of large anomalous Nernst effect in Weyl magnet-based alloy films Peer-reviewed

    Shun Noguchi, Kohei Fujiwara, Yuki Yanagi, Michi-To Suzuki, Takamasa Hirai, Takeshi Seki, Ken-ichi Uchida, Atsushi Tsukazaki

    Nature Physics　20　254-260　2024/01/08

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41567-023-02293-z 　

    ISSN： 1745-2473

    eISSN： 1745-2481

  15. Effect of multilayering and crystal orientation on spin-orbit torque efficiency in Ni/Pt layer stacking Peer-reviewed

    A. Sud, Y.-C. Lau, J. Brierley, H. Kurebayashi, T. Seki

    Physical Review Materials　7　(12)　124410-1-124410-13　2023/12/20

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevmaterials.7.124410 　

    eISSN： 2475-9953

  16. Perspective on spin-based wave-parallel computing Peer-reviewed

    Makoto Kohda, Takeshi Seki, Yasushi Yuminaka, Tetsuya Uemura, Keito Kikuchi, Gian Salis

    Applied Physics Letters　123　(19)　190502-1-190502-18　2023/11/06

    Publisher: AIP Publishing

    DOI： 10.1063/5.0168083 　

    ISSN： 0003-6951

    eISSN： 1077-3118

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    Waves exhibit unique characteristics, such as diffraction and interference, which distinguishes them from the particle nature of electrons currently used for binary and sequential data processing and storage. In the solid state, wave properties can be found in electron spin waves in semiconductors or magnons in magnetic materials. These are useful for communication, processing and storage, and allow multiplexing of the information. Given this perspective, after introducing the information theory of wave-parallel computing and arguing the fundamental properties necessary for implementation with wave-based information carriers, we specifically examine how electron spin waves and magnons can be used as information carriers for processing and storage. Then, after explaining the fundamental physics of the electron spin wave based on the persistent spin helix state, we assess the potential of magnon-assisted magnetization switching for realizing the selective writing and reading of multiplexed information. Ferromagnet/semiconductor hybrid structures are emphasized as a platform for generating and controlling both electron spin waves and magnons. Interconversion among light helicity, electron spin waves and magnons is also discussed. Finally, we show several challenges and provide an outlook on the key steps that must be demonstrated for implementing spin-based wave-parallel computing.

  17. Magnetic Layer Thickness Influence on Magnetoelastic Properties Anisotropy in Co2Fe0.4Mn0.6Si Heusler Alloy Thin Films Peer-reviewed

    Adam Nabialek, Oleksandr Chumak, Takeshi Seki, Koki Takanashi, Lech T. Baczewski, Henryk Szymczak

    IEEE Transactions on Magnetics　59　(11)　1-5　2023/11

    Publisher: Institute of Electrical and Electronics Engineers (IEEE)

    DOI： 10.1109/tmag.2023.3287324 　

    ISSN： 0018-9464

    eISSN： 1941-0069

  18. Influence of the strain effect on magnetocrystalline anisotropy in Co2Fe0.4Mn0.6Si Heusler alloys Peer-reviewed

    A. Nabiałek, O. M. Chumak, P. Aleshkevych, J. Z. Domagala, A. Pacewicz, B. Salski, J. Krupka, T. Seki, K. Takanashi, L. T. Baczewski, H. Szymczak

    Scientific Reports　13　(1)　17016-1-17016-9　2023/10/09

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41598-023-43979-x 　

    eISSN： 2045-2322

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    Abstract The perpendicular magnetocrystalline anisotropy, magnetoelastic properties as well as the Gilbert damping factor in Co2Fe0.4Mn0.6Si thin films were found to depend on a magnetic layer thickness, and they can be also tuned by the application of additional Ag buffer layer. The tetragonal distortion of a magnetic layer was found to increase with decreasing thickness, and after the application of an additional Ag buffer layer, the character of this distortion was changed from tensile to compressive in the plane of a film. A correlation between the tetragonal distortion and perpendicular magnetocrystalline anisotropy was found. However, the magnitude of the observed tetragonal distortion for most samples seems to be too small to explain alone the experimentally found large magnitude of the perpendicular magnetocrystalline anisotropy. For these samples, other mechanisms including both surface and volume effects must be taken into account.

  19. Impact of epitaxial strain relaxation on ferromagnetism in a freestanding La2 / 3Sr1 / 3MnO3 membrane Peer-reviewed

    Ryuji Atsumi, Junichi Shiogai, Takumi Yamazaki, Takeshi Seki, Kohei Ueda, Jobu Matsuno

    Japanese Journal of Applied Physics　62　(10)　100902-100902　2023/10/01

    Publisher: IOP Publishing

    DOI： 10.35848/1347-4065/ad0270 　

    ISSN： 0021-4922

    eISSN： 1347-4065

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    Abstract Manganite perovskites host emerging physical properties of strongly-correlated electrons with charge, spin, and lattice degrees of freedom. Using the epitaxial lift-off technique, we report enhancement of saturation magnetization and the ferromagnetic transition temperature of freestanding La2/3Sr1/3MnO3 membrane compared with as-grown film on SrTiO3 substrate involving lateral tensile strain. Structural analysis reveals shrinkage of unit-cell volume by tensile strain relaxation in the freestanding membrane, which causes enhancement of the ferromagnetic interaction. The impact of the microscopic lattice deformation on the ferromagnetism of La2/3Sr1/3MnO3 indicates a high potential of this material for flexible electronics applications with intriguing functionalities in strongly-correlated electron systems.

  20. Intercorrelated anomalous Hall and spin Hall effect in kagome-lattice Co3Sn2S2-based shandite films Peer-reviewed

    Yong-Chang Lau, Junya Ikeda, Kohei Fujiwara, Akihiro Ozawa, Jiaxin Zheng, Takeshi Seki, Kentaro Nomura, Liang Du, Quansheng Wu, Atsushi Tsukazaki, Koki Takanashi

    Physical Review B　108　(6)　064429-1-064429-11　2023/08/25

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.108.064429 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  21. Influence of epitaxial growth on spin current transmission of NiO films Peer-reviewed

    Takumi Yamazaki, Takeshi Seki, Takahide Kubota, Koki Takanashi

    Applied Physics Express　16　(8)　083003-083003　2023/08/01

    Publisher: IOP Publishing

    DOI： 10.35848/1882-0786/acecd5 　

    ISSN： 1882-0778

    eISSN： 1882-0786

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    Abstract This letter reports the effect of the epitaxial growth of NiO films on its spin current transmission. Two sample series of Pt/NiO/CoFeB, including epitaxial and polycrystalline NiO, were prepared using different deposition conditions. The spin current transmission of NiO is evaluated using the thermo-spin effects in the trilayers. Epitaxial NiO exhibits a non-monotonic behavior in the NiO thickness dependence of spin current transmission, while this behavior is smeared out in polycrystalline NiO. The non-monotonic behavior implies the presence of multiple spin transport mechanisms, which becomes apparent with epitaxial growth.

  22. Magnetization switching process by dual spin–orbit torque in interlayer exchange-coupled systems Peer-reviewed

    Hiroto Masuda, Yuta Yamane, Takeshi Seki, Klaus Raab, Takaaki Dohi, Rajkumar Modak, Ken-ichi Uchida, Jun'ichi Ieda, Mathias Kläui, Koki Takanashi

    Applied Physics Letters　122　(16)　162402-1-162402-7　2023/04/17

    Publisher: AIP Publishing

    DOI： 10.1063/5.0140328 　

    ISSN： 0003-6951

    eISSN： 1077-3118

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    We report current-induced magnetization switching in Pt/Co/Ir/Co/Pt multilayers with different Ir layer thicknesses ( tIr), where the perpendicularly magnetized Co layers are coupled ferromagnetically or antiferromagnetically through an interlayer exchange coupling and are sandwiched by the Pt spin Hall layers. The domain structures formed during switching vary depending on the magnetization alignment, i.e., a ferromagnetically coupled or antiferromagnetically coupled configuration. These results clarify the macroscopic picture of switching process for interlayer exchange-coupled systems. The local picture of the switching process is also examined by a numerical calculation based on a macrospin model, which reveals the switching dynamics triggered by dual spin–orbit torques for both antiferromagnetically and ferromagnetically coupled cases. The numerical calculation shows that the dual spin–orbit torques from the two Pt layers effectively act on the two Co layers not only for the antiferromagnetically coupled case but also for the ferromagnetically coupled one. Our findings deepen the understanding of the switching mechanism in a magnetic multilayer and provide an avenue to design spintronic devices with more efficient spin–orbit torque switching.

  23. Lattice constants and magnetism of L10-ordered FePt under high pressure Peer-reviewed

    S. Sawada, K. Okai, H. Fukui, R. Takahashi, N. Ishimatsu, H. Maruyama, N. Kawamura, S. Kawaguchi, N. Hirao, T. Seki, K. Takanashi, S. Ohmura, H. Wadati

    Applied Physics Letters　122　(15)　152406-1-152406-5　2023/04/10

    Publisher: AIP Publishing

    DOI： 10.1063/5.0139441 　

    ISSN： 0003-6951

    eISSN： 1077-3118

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    We studied the relationship between the lattice constant and magnetism of [Formula: see text]-ordered FePt under high pressure by means of first-principles calculations and synchrotron x-ray measurements. Based on our calculations, we found that the c/ a ratio shows a local maximum at ∼20 GPa and that the Pt magnetic moment first remains almost unchanged and is sharply suppressed at ∼60 GPa. As for the c/ a, we experimentally verified the local maximum at ∼20 GPa by powder x-ray diffraction. We also measured the x-ray magnetic circular dichroism at the Pt L edge up to ∼20 GPa. Any significant change in the Pt magnetic moment was not observed in agreement with the calculations. These results, thus, indicate that magnetic states, where the magnetization of Fe decreased and that of Pt did not change, can be created in [Formula: see text]-ordered FePt by lattice deformation under high pressure.

  24. Current-induced crystallisation in a Heusler-alloy-based giant magnetoresistive junction for neuromorphic potentiation Peer-reviewed

    Zhenyu Zhou, William Frost, David C. Lloyd, Takeshi Seki, Takahide Kubota, Rafael Ramos, Eiji Saitoh, Koki Takanashi, Atsufumi Hirohata

    Journal of Magnetism and Magnetic Materials　571　170575-1-170575-5　2023/04

    Publisher: Elsevier BV

    DOI： 10.1016/j.jmmm.2023.170575 　

    ISSN： 0304-8853

  25. Enhancement of spin-charge conversion efficiency for Co3Sn2S2 across transition from paramagnetic to ferromagnetic phase Peer-reviewed

    Takeshi Seki, Yong-Chang Lau, Junya Ikeda, Kohei Fujiwara, Akihiro Ozawa, Satoshi Iihama, Kentaro Nomura, Atsushi Tsukazaki

    Physical Review Research　5　(1)　013222-1-013222-14　2023/03/31

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevresearch.5.013222 　

    eISSN： 2643-1564

  26. Superconducting fluctuation effect on epitaxially layered films of superconductor NbN and half-metallic Heusler alloy Co2MnSi Peer-reviewed

    Iduru Shigeta, Shuta Oku, Takahide Kubota, Shojiro Kimura, Takeshi Seki, Bunju Shinozaki, Satoshi Awaji, Koki Takanashi, Masahiko Hiroi

    AIP Advances　13　(2)　025116-1-025116-5　2023/02/01

    Publisher: AIP Publishing

    DOI： 10.1063/9.0000584 　

    eISSN： 2158-3226

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    Superconducting properties were investigated in epitaxially layered films consisting of superconductor NbN and half-metallic Heusler alloy Co2MnSi (CMS). Temperature dependence of the electrical resistivity ρ( T) was measured by applying perpendicular magnetic fields to the surface of NbN/CMS films. With the increase of the CMS thickness dCMS, the upper critical field μ0 Hc2 decreased monotonically, but the superconducting transition temperature Tc had the minimum of 10.1 K at dCMS ≈ 5 nm. The Tc behavior was in qualitative agreement with the theory of the π-coupling. The pair-breaking parameter δ determined by the superconducting fluctuation theory took the maximum at dCMS = 3 ∼ 5 nm, which would be related to the minimum of Tc. The experimental results reveal that the superconductivity of the NbN layer in NbN/CMS films is affected by the interplay between the superconducting NbN layer and the half-metallic CMS layer.

  27. Antiferromagnetic Films and Their Applications Peer-reviewed

    Atsufumi Hirohata, David C. Lloyd, Takahide Kubota, Takeshi Seki, Koki Takanashi, Hiroaki Sukegawa, Zhenchao Wen, Seiji Mitani, Hiroki Koizumi

    IEEE Access　11　117443-117459　2023

    Publisher: Institute of Electrical and Electronics Engineers (IEEE)

    DOI： 10.1109/access.2023.3326448 　

    eISSN： 2169-3536

  28. Sm-Co-based amorphous alloy films for zero-field operation of transverse thermoelectric generation Peer-reviewed

    Rajkumar Modak, Yuya Sakuraba, Takamasa Hirai, Takashi Yagi, Hossein Sepehri-Amin, Weinan Zhou, Hiroto Masuda, Takeshi Seki, Koki Takanashi, Tadakatsu Ohkubo, Ken-ichi Uchida

    Science and Technology of Advanced Materials　23　(1)　767-782　2022/12/31

    Publisher: Informa UK Limited

    DOI： 10.1080/14686996.2022.2138538 　

    ISSN： 1468-6996

    eISSN： 1878-5514

  29. Perpendicularly magnetized epitaxial Co/Ni multilayers grown on Ru(0001) layers by alternate monoatomic layer deposition Peer-reviewed

    Keita Ito, Naoto Kikuchi, Takeshi Seki, Koki Takanashi

    Journal of Magnetism and Magnetic Materials　563　169908-1-169908-6　2022/12

    Publisher: Elsevier BV

    DOI： 10.1016/j.jmmm.2022.169908 　

    ISSN： 0304-8853

  30. Elemental Doping and Interface Effects on Spin–Orbit Torques in CoSi‐Based Topological Semimetal Thin Films Peer-reviewed

    Ke Tang, Zhenchao Wen, Takeshi Seki, Hiroaki Sukegawa, Seiji Mitani

    Advanced Materials Interfaces　9　(36)　2201332-1-2201332-7　2022/12

    Publisher: Wiley

    DOI： 10.1002/admi.202201332 　

    ISSN： 2196-7350

    eISSN： 2196-7350

  31. Electrical detection of domain evolution in magnetic Weyl semimetal Co3Sn2S2 submicrometer-wide wire devices Peer-reviewed

    Junichi Shiogai, Junya Ikeda, Kohei Fujiwara, Takeshi Seki, Koki Takanashi, Atsushi Tsukazaki

    Physical Review Materials　6　(11)　114203-1-114203-9　2022/11/30

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevmaterials.6.114203 　

    eISSN： 2475-9953

  32. Anisotropy of magnetoelastic properties in epitaxial Co2FexMn1−xSi Heusler alloy thin films Peer-reviewed

    A. Nabiałek, O. Chumak, A. Lynnyk, J. Z. Domagała, A. Pacewicz, B. Salski, J. Krupka, T. Yamamoto, T. Seki, K. Takanashi, L. T. Baczewski, H. Szymczak

    Physical Review B　106　(5)　054406-1-054406-11　2022/08/02

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.106.054406 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  33. Thickness dependence of anomalous Hall and Nernst effects in Ni-Fe thin films Peer-reviewed

    Takumi Yamazaki, Takeshi Seki, Rajkumar Modak, Keita Nakagawara, Takamasa Hirai, Keita Ito, Ken-ichi Uchida, Koki Takanashi

    Physical Review B　105　(21)　214416-1-214416-9　2022/06/13

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.105.214416 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  34. Large Antisymmetric Interlayer Exchange Coupling Enabling Perpendicular Magnetization Switching by an In-Plane Magnetic Field Peer-reviewed

    Hiroto Masuda, Takeshi Seki, Yuta Yamane, Rajkumar Modak, Ken-ichi Uchida, Jun’ichi Ieda, Yong-Chang Lau, Shunsuke Fukami, Koki Takanashi

    Physical Review Applied　17　054036-1-054036-9　2022/05

    DOI： 10.1103/PhysRevApplied.17.054036 　

  35. All-Optical Detection of Spin Pumping and Giant Interfacial Spin Transparency in Co2Fe0.4Mn0.6Si/Pt Heterostructure Peer-reviewed

    Koustuv Dutta, Surya N Panda, Takeshi Seki, Santanu Pan, Koki Takanashi, Anjan Barman

    Advanced Quantum Technologies　5　2200033-1-2200033-10　2022/05

    DOI： 10.1002/qute.202200033 　

  36. Strain-Induced Large Anomalous Nernst Effect in Polycrystalline Co2MnGa/AlN Multilayers Peer-reviewed

    Jian Wang, Yong-Chang Lau, Weinan Zhou, Takeshi Seki, Yuya Sakuraba, Takahide Kubota, Keita Ito, Koki Takanashi

    ADVANCED ELECTRONIC MATERIALS　8　2101380-1-2101380-8　2022/04

    DOI： 10.1002/aelm.202101380 　

    ISSN： 2199-160X

  37. Effect of disorder and vacancy defects on electrical transport properties of Co2MnGa thin films grown by magnetron sputtering Peer-reviewed

    A. Miyashita, M. Maekawa, C. Suzuki, S. Yamamoto, A. Kawasuso, J. Wang, T. Seki, R. Y. Umetsu, K. Takanashi

    Journal of Applied Physics　130　(22)　225301-225301　2021/12/14

    Publisher: AIP Publishing

    DOI： 10.1063/5.0071807 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  38. Tuning scalar spin chirality in ultrathin films of the kagome-lattice ferromagnet Fe3Sn Peer-reviewed

    Kohei Fujiwara, Yasuyuki Kato, Takeshi Seki, Kentaro Nomura, Koki Takanashi, Yukitoshi Motome, Atsushi Tsukazaki

    Communications Materials　2　(1)　113-1-113-7　2021/11/09

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s43246-021-00218-y 　

    eISSN： 2662-4443

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    <title>Abstract</title>Non-coplanar spin textures with finite scalar spin chirality can be artificially induced at surfaces and interfaces through the interfacial Dzyaloshinskii-Moriya interaction. However, stabilizing a proper magnetic skyrmion crystal via this route remains elusive. Here, using an epitaxial bilayer of platinum and geometrically frustrated kagome-lattice ferromagnet Fe3Sn, we show the possible formation of a two-dimensional skyrmion crystal under well-regulated Fe3Sn thickness conditions. Magnetization measurements reveal that the magnetic anisotropy is systematically varied from an inherent in-plane type to a perpendicular type with the thickness reduction. Below approximately 0.5 nm, we clearly detect a topological Hall effect that provides evidence for finite scalar spin chirality. Our topological Hall effect analysis, combined with theoretical simulations, not only establishes its interfacial Dzyaloshinskii-Moriya interaction origin, but also indicates the emergence of a stable skyrmion crystal phase, demonstrating the potential of kagome-lattice ferromagnets in spin chirality engineering using thin-film nanostructures.

  39. Spin-orbit torque in a Ni-Fe single layer Peer-reviewed

    Takeshi Seki, Yong-Chang Lau, Satoshi Iihama, Koki Takanashi

    Physical Review B　104　(9)　094430-1-094430-1　2021/09/24

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.104.094430 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  40. Spin Hall effect in a non-equilibrium Cu76Ir24 alloy measured at various temperatures Peer-reviewed

    Hiroto Masuda, Rajkumar Modak, Takeshi Seki, Ken-ichi Uchida, Yong-Chang Lau, Junsaku Nitta, Koki Takanashi

    AIP Advances　11　(9)　095221-1-095221-5　2021/09/20

    Publisher: AIP Publishing

    DOI： 10.1063/5.0065253 　

    eISSN： 2158-3226

  41. Highly fcc-textured Pt–Al alloy films grown on MgO(001) showing enhanced spin Hall efficiency Peer-reviewed

    Yong-Chang Lau, Takeshi Seki, Koki Takanashi

    APL Materials　9　(8)　081113-1-081113-10　2021/08/01

    Publisher: AIP Publishing

    DOI： 10.1063/5.0052544 　

    eISSN： 2166-532X

  42. Spin Hall effect in a spin-1 chiral semimetal Peer-reviewed

    Ke Tang, Yong-Chang Lau, Kenji Nawa, Zhenchao Wen, Qingyi Xiang, Hiroaki Sukegawa, Takeshi Seki, Yoshio Miura, Koki Takanashi, Seiji Mitani

    Physical Review Research　3　(3)　033101-1-033101-10　2021/07/29

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevresearch.3.033101 　

    eISSN： 2643-1564

  43. Temperature dependence of anisotropic magneto-Seebeck effect in NiPt alloys Peer-reviewed

    Takamasa Hirai, Rajkumar Modak, Asuka Miura, Takeshi Seki, Koki Takanashi, Ken-ichi Uchida

    Applied Physics Express　14　(7)　073001-1-073001-4　2021/07/01

    Publisher: IOP Publishing

    DOI： 10.35848/1882-0786/ac057c 　

    ISSN： 1882-0778

    eISSN： 1882-0786

  44. Origin of magnetic anisotropy, role of induced magnetic moment, and all-optical magnetization switching for Co100−xGdx/Pt multilayers Peer-reviewed

    J. Wang, T. Seki, Y.-C. Lau, Y. K. Takahashi, K. Takanashi

    APL Materials　9　(6)　061110-1-061110-8　2021/06/01

    Publisher: AIP Publishing

    DOI： 10.1063/5.0050985 　

    eISSN： 2166-532X

  45. Two-dimensionality of metallic surface conduction in Co3Sn2S2 thin films Peer-reviewed

    Junya Ikeda, Kohei Fujiwara, Junichi Shiogai, Takeshi Seki, Kentaro Nomura, Koki Takanashi, Atsushi Tsukazaki

    Communications Physics　4　(1)　117-1-117-6　2021/06

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s42005-021-00627-y 　

    eISSN： 2399-3650

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    <title>Abstract</title>Two-dimensional (2D) surface of the topological materials is an attractive channel for the electrical conduction reflecting the linearly-dispersive electronic bands. Thickness-dependent sheet conductance measurement is a reliable method to evaluate the 2D and three-dimensional (3D) electrical conducting channel separately but has rarely been applied for Weyl semimetals. By applying this method to thin films of a Weyl semimetal Co3Sn2S2, here we show that the 2D conducting channel clearly emerges under the ferromagnetic phase, indicating a formation of the Fermi arcs projected from Weyl nodes. Comparison between 3D conductivity and 2D conductance provides the effective thickness of the surface conducting region being estimated to be approximately 20 nm, which would reflect the Weyl feature of electronic bands of the Co3Sn2S2. The emergent surface conduction will provide a pathway to activate quantum and spintronic transport features stemming from a Weyl node in thin-film-based devices.

  46. Evaluation of edge domains in giant magnetoresistive junctions Peer-reviewed

    William Frost, Takeshi Seki, Takahide Kubota, Rafael Ramos, Eiji Saitoh, Koki Takanashi, Atsufumi Hirohata

    Applied Physics Letters　118　(17)　172405-1-172405-5　2021/04/26

    Publisher: AIP Publishing

    DOI： 10.1063/5.0049315 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  47. Magnetoelastic interactions and magnetic damping in Co2Fe0.4Mn0.6Si and Co2FeGa0.5Ge0.5 Heusler alloys thin films for spintronic applications Peer-reviewed

    O. M. Chumak, A. Pacewicz, A. Lynnyk, B. Salski, T. Yamamoto, T. Seki, J. Z. Domagala, H. Głowiński, K. Takanashi, L. T. Baczewski, H. Szymczak, A. Nabiałek

    Scientific Reports　11　7608-1-7608-12　2021/04

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41598-021-87205-y 　

    eISSN： 2045-2322

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    <title>Abstract</title>Co2Fe0.4Mn0.6Si (CFMS) and Co2FeGa0.5Ge0.5 (CFGG) Heusler alloys are among the most promising thin film materials for spintronic devices due to a high spin polarization, low magnetic damping and giant/tunneling magnetoresistance ratios. Despite numerous investigations of Heusler alloys magnetic properties performed up to now, magnetoelastic effects in these materials remain not fully understood; due to quite rare studies of correlations between magnetoelastic and other magnetic properties, such as magnetic dissipation or magnetic anisotropy. In this research we have investigated epitaxial CFMS and CFGG Heusler alloys thin films of thickness in the range of 15–50 nm. We have determined the magnetoelastic tensor components and magnetic damping parameters as a function of the magnetic layer thickness. Magnetic damping measurements revealed the existence of non-Gilbert dissipation related contributions, including two-magnon scattering and spin pumping phenomena. Magnetoelastic constant B11 values and the effective magnetic damping parameter α<italic>eff</italic> values were found to be in the range of − 6 to 30 × 106 erg/cm3 and between 1 and 12 × 10–3, respectively. The values of saturation magnetostriction λS for CFMS Heusler alloy thin films were also obtained using the strain modulated ferromagnetic resonance technique. The correlation between α<italic>eff</italic> and B11, depending on magnetic layer thickness was determined based on the performed investigations of the above mentioned magnetic properties.

  48. Robust perpendicular magnetic anisotropy of Co3Sn2S2 phase in sulfur deficient sputtered thin films Peer-reviewed

    Junichi Shiogai, Junya Ikeda, Kohei Fujiwara, Takeshi Seki, Koki Takanashi, Atsushi Tsukazaki

    Physical Review Materials　5　(2)　024403-1-024403-19　2021/02/09

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevmaterials.5.024403 　

    eISSN： 2475-9953

  49. Magnetization switching induced by spin–orbit torque from Co2MnGa magnetic Weyl semimetal thin films Peer-reviewed

    Ke Tang, Zhenchao Wen, Yong-Chang Lau, Hiroaki Sukegawa, Takeshi Seki, Seiji Mitani

    Applied Physics Letters　118　(6)　062402-1-062402-6　2021/02/08

    Publisher: AIP Publishing

    DOI： 10.1063/5.0037178 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  50. Critical thickness for the emergence of Weyl features in Co3Sn2S2 thin films Peer-reviewed

    Junya Ikeda, Kohei Fujiwara, Junichi Shiogai, Takeshi Seki, Kentaro Nomura, Koki Takanashi, Atsushi Tsukazaki

    Communications Materials　2　(1)　18-1-18-7　2021/02

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s43246-021-00122-5 　

    eISSN： 2662-4443

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    <title>Abstract</title>Magnetic Weyl semimetals are quantum phases of matter arising from the interplay of linearly dispersive bands, spin-orbit coupling, and time reversal symmetry breaking. This can be realised, for example, in Co3Sn2S2, based on a cobalt kagome lattice and characterised by intriguing phenomena such as large anomalous Hall effect, Nernst effect, and water oxidation. Here, we attempt to determine the robustness of the twofold necessary conditions for the emergence of the magnetic Weyl semimetal phase in Co3Sn2S2 ultrathin films. Except for two-dimensional layered materials, a reduction of thickness generally makes it difficult to develop topological character and ferromagnetic long-range order. In Co3Sn2S2 films, while ferromagnetic ordering appears robustly even in average thicknesses of one or two unit cells with island-like polycrystalline domains, the anomalous Hall conductivity appears only above a critical thickness of approximately 10 nm. The emergence of surface conduction and large anomalous Hall effect implies the distinct contribution of Weyl nodes and their Berry curvature. These findings reveal an exotic feature of Weyl physics in thin-film based superstructures as well as a potential for future applications in electronic devices.

  51. Enhancement of the anomalous Nernst effect in Ni/Pt superlattices Peer-reviewed

    T. Seki, Y. Sakuraba, K. Masuda, A. Miura, M. Tsujikawa, K. Uchida, T. Kubota, Y. Miura, M. Shirai, K. Takanashi

    Physical Review B　103　(2)　L020402-1-L020402-7　2021/01/06

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.103.l020402 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  52. High spin mixing conductance and spin interface transparency at the interface of a Co2Fe0.4Mn0.6Si Heusler alloy and Pt Peer-reviewed

    Braj Bhusan Singh, Koustuv Roy, Pushpendra Gupta, Takeshi Seki, Koki Takanashi, Subhankar Bedanta

    NPG Asia Materials　13　(1)　9-1-9-11　2021/01

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41427-020-00268-7 　

    ISSN： 1884-4049

    eISSN： 1884-4057

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    <title>Abstract</title>Ferromagnetic materials exhibiting low magnetic damping (<italic>α</italic>) and moderately high-saturation magnetization are required from the viewpoints of generation, transmission, and detection of spin waves. Since spin-to-charge conversion efficiency is another important parameter, high spin mixing conductance <inline-formula><alternatives><tex-math>$$({g_{r}^{\uparrow \downarrow } })$$</tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>(</mml:mo> <mml:mrow> <mml:msubsup> <mml:mrow> <mml:mi>g</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>r</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>↑</mml:mi> <mml:mi>↓</mml:mi> </mml:mrow> </mml:msubsup> </mml:mrow> <mml:mo>)</mml:mo> </mml:mrow> </mml:math></alternatives></inline-formula> is the key for efficient spin-to-charge conversion. Full Heusler alloys, e.g., Co2Fe0.4Mn0.6Si (CFMS), which are predicted to be 100% spin-polarized, exhibit low <italic>α</italic>. However, <inline-formula><alternatives><tex-math>$$g_r^{ \uparrow \downarrow }$$</tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mrow> <mml:mi>g</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>r</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>↑</mml:mi> <mml:mi>↓</mml:mi> </mml:mrow> </mml:msubsup> </mml:math></alternatives></inline-formula> at the interface between CFMS and a paramagnet is not fully understood. Here, we report investigations of spin pumping and the inverse spin Hall effect in CFMS/Pt bilayers. Damping analysis indicates the presence of significant spin pumping at the interface of CFMS and Pt, which is also confirmed by the detection of an inverse spin Hall voltage. We show that in CFMS/Pt, <inline-formula><alternatives><tex-math>$$g_r^{ \uparrow \downarrow }$$</tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mrow> <mml:mi>g</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>r</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>↑</mml:mi> <mml:mi>↓</mml:mi> </mml:mrow> </mml:msubsup> </mml:math></alternatives></inline-formula> (1.70 × 1020 m−2) and the interface transparency (83%) are higher than the values reported for other ferromagnetic/heavy metal systems. We observed a spin Hall angle of ~0.026 for the CFMS/Pt bilayer system.

  53. Large spin-Hall effect in non-equilibrium binary copper alloys beyond the solubility limit Peer-reviewed

    Hiroto Masuda, Rajkumar Modak, Takeshi Seki, Ken-ichi Uchida, Yong-Chang Lau, Yuya Sakuraba, Ryo Iguchi, Koki Takanashi

    Communications Materials　1　(1)　75-1-75-8　2020/12

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s43246-020-00076-0 　

    eISSN： 2662-4443

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    <title>Abstract</title> Non-magnetic materials exhibiting large spin-Hall effect (SHE) are eagerly desired for high-performance spintronic devices. Here, we report that non-equilibrium Cu-Ir binary alloys with compositions beyond the solubility limit are candidates as spin-Hall materials, even though Cu and Ir do not exhibit remarkable SHE themselves. Thanks to non-equilibrium thin film fabrication, the Cu-Ir binary alloys are obtained over a wide composition range even though they are thermodynamically unstable in bulk form. We investigate the SHE of Cu-Ir by exploiting a combinatorial technique based on spin Peltier imaging, and find that the optimum Ir concentration for enhancing SHE is around 25 at.%. We achieve a large spin-Hall angle of 6.29 ± 0.19% for Cu76Ir24. In contrast to Cu-Ir, non-equilibrium Cu-Bi binary alloys do not show remarkable SHE. Our discovery opens a new direction for the exploration of spin-Hall materials.

  54. High-temperature dependence of anomalous Ettingshausen effect in SmCo5-type permanent magnets Peer-reviewed

    Asuka Miura, Keisuke Masuda, Takamasa Hirai, Ryo Iguchi, Takeshi Seki, Yoshio Miura, Hiroki Tsuchiura, Koki Takanashi, Ken-ichi Uchida

    Applied Physics Letters　117　(8)　082408-1-082408-6　2020/08/24

    Publisher: AIP Publishing

    DOI： 10.1063/5.0023111 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  55. Perpendicularly magnetized Ni/Pt (001) epitaxial superlattice Peer-reviewed

    T. Seki, M. Tsujikawa, K. Ito, K. Uchida, H. Kurebayashi, M. Shirai, K. Takanashi

    Physical Review Materials　4　064413-1-064413-9　2020/06/19

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevmaterials.4.064413 　

    eISSN： 2475-9953

  56. Interlayer exchange coupling and spin Hall effect through an Ir-doped Cu nonmagnetic layer Peer-reviewed

    Hiroto Masuda, Takeshi Seki, Yong-Chang Lau, Takahide Kubota, Koki Takanashi

    Physical Review B　101　224413-1-224413-10　2020/06/08

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.101.224413 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  57. Ultrafast demagnetization mechanism in half-metallic Heusler alloy thin films controlled by the Fermi level Peer-reviewed

    Santanu Pan, Takeshi Seki, Koki Takanashi, Anjan Barman

    Physical Review B　101　224412-1-224412-8　2020/06/08

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevb.101.224412 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  58. Element-selectively tracking ultrafast demagnetization process in Co/Pt multilayer thin films by the resonant magneto-optical Kerr effect Peer-reviewed

    Kohei Yamamoto, Souliman El Moussaoui, Yasuyuki Hirata, Susumu Yamamoto, Yuya Kubota, Shigeki Owada, Makina Yabashi, Takeshi Seki, Koki Takanashi, Iwao Matsuda, Hiroki Wadati

    Applied Physics Letters　116　172406-1-172406-5　2020/04/27

    Publisher: AIP Publishing

    DOI： 10.1063/5.0005393 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  59. Spin-mediated charge-to-heat current conversion phenomena in ferromagnetic binary alloys Peer-reviewed

    Asuka Miura, Ryo Iguchi, Takeshi Seki, Koki Takanashi, Ken-ichi Uchida

    Physical Review Materials　4　034409-1-034409-13　2020/03/24

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevmaterials.4.034409 　

    eISSN： 2475-9953

  60. Structural-order dependence of anomalous Hall effect in Co2MnGa topological semimetal thin films Peer-reviewed

    Q. Wang, Z. Wen, T. Kubota, T. Seki, K. Takanashi

    Applied Physics Letters　115　252401-1-252401-5　2019/12

    DOI： 10.1063/1.5127553 　

  61. Spin-charge conversion in NiMnSb Heusler alloy films Peer-reviewed

    Z. Wen, Z. Qiu, S. Tölle, C. Gorini, T. Seki, D. Hou, T. Kubota, U. Eckern, E. Saitoh, K. Takanashi

    Science Advances　5　eaaw9337-1-eaaw9337-7　2019/12

    DOI： 10.1126/sciadv.aaw9337 　

  62. Ultrafast demagnetization of Pt magnetic moment in L10-FePt probed by magnetic circular dichroism at a hard x-ray free electron laser Peer-reviewed

    K. Yamamoto, Y. Kubota, M. Suzuki, Y. Hirata, K. Carva, M. Berritta, K. Takubo, Y. Uemura, R. Fukaya, K. Tanaka, W. Nishimura, T. Ohkochi, T. Katayama, T. Togashi, K. Tamasaku, M. Yabashi, Y. Tanaka, T. Seki, K. Takanashi, P. M. Oppeneer, H. Wadati

    New Journal of Physics　21　123010-1-123010-9　2019/12

    DOI： 10.1088/1367-2630/ab5ac2 　

  63. Large spin anomalous Hall effect in L10-FePt: Symmetry and magnetization switching Peer-reviewed

    T. Seki, S. Iihama, T. Taniguchi, K. Takanashi

    Physical Review B　100　144427-1-144427-8　2019/10

    DOI： 10.1103/PhysRevB.100.144427 　

  64. Spinmotive force in the out-of-plane direction generated by spin wave excitations in an exchange-coupled bilayer element Peer-reviewed

    W. Zhou, T. Seki, H. Imamura, J. Ieda, K. Takanashi

    Physical Review B　100　094424-1-094424-5　2019/09

    DOI： 10.1103/PhysRevB.100.094424 　

  65. Direct observation of magneto-Peltier effect in current-in-plane giant magnetoresistive spin valve Peer-reviewed

    Hiroyasu Nakayama, Tomoya Nakatani, Ryo Iguchi, Takeshi Seki, Ken Ichi Uchida

    Applied Physics Letters　115　(9)　092406-1-092406-5　2019/08/26

    DOI： 10.1063/1.5120569 　

    ISSN： 0003-6951

  66. Tunability of Domain Structure and Magnonic Spectra in Antidot Arrays of Heusler Alloy Peer-reviewed

    S. Mallick, S. Mondal, T. Seki, S. Sahoo, T. Forrest, F. Maccherozzi, Z. Wen, S. Barman, A. Barman, K. Takanashi, S. Bedanta

    Physical Review Applied　12　014043-1-014043-9　2019/07

    DOI： 10.1103/PhysRevApplied.12.014043 　

  67. Polarization control with an X-ray phase retarder for high-time-resolution pump–probe experiments at SACLA Peer-reviewed

    Y. Kubota, M. Suzuki, T. Katayama, K. Yamamoto, K. Tono, Y. Inubushi, T. Seki, K. Takanashi, H. Wadati, M. Yabashi

    Journal of Synchrotron Radiation　26　1139-1143　2019/06

  68. Evaluation of spin–orbit torque in a L10-FePt single layer and a L10-FePt/Pt bilayer Peer-reviewed

    T. Sato, T. Seki, M. Kohda, J. Ryu, H. Gamou, S. Karube, K. Takanashi, J. Nitta

    Japanese Journal of Applied Physics　58　060915R-1-060915R-5　2019/05

    DOI： 10.7567/1347-4065/ab1e5a 　

  69. Ferromagnetic Co3Sn2S2 thin films fabricated by co-sputtering Peer-reviewed

    K. Fujiwara, J. Ikeda, J. Shiogai, T. Seki, K. Takanashi, A. Tsukazaki

    Japanese Journal of Applied Physics　58　050912R-1-050912R-4　2019/04

    DOI： 10.7567/1347-4065/ab12ff 　

  70. Fe-Sn nanocrystalline films for flexible magnetic sensors with high thermal stability Peer-reviewed

    Y. Satake, K. Fujiwara, J. Shiogai, T. Seki, A. Tsukazaki

    Scientific Reports　9　3282-1-3282-7　2019/03

    DOI： 10.1038/s41598-019-39817-8 　

  71. Anomalous Hall Effect and Anisotropic Magnetoresistance in Perpendicularly Magnetized FePt1-xPdx Films Peer-reviewed

    T. Seki, S. Kikushima, K. Takanashi

    Journal of the Magnetics Society of Japan　43　29-33　2019/03

    DOI： 10.3379/msjmag.1903R004 　

  72. Anomalous Ettingshausen effect in ferrimagnetic Co-Gd Peer-reviewed

    Takeshi Seki, Asuka Miura, Ken Ichi Uchida, Takahide Kubota, Koki Takanashi

    Applied Physics Express　12　(2)　023006-1-023006-4　2019/02

    DOI： 10.7567/1882-0786/aafb5a 　

    ISSN： 1882-0778

    eISSN： 1882-0786

  73. Spin-Orbit-Torque Memory Operation of Synthetic Antiferromagnets Peer-reviewed

    T. Moriyama, W. Zhou, T. Seki, K. Takanashi, T. Ono

    Physical Review Letters　121　167202-1-167202-5　2018/10

    DOI： 10.1103/PhysRevLett.121.167202 　

  74. Spin-Hall and anisotropic magnetoresistance in ferrimagnetic Co-Gd/Pt layers Peer-reviewed

    W. Zhou, T. Seki, T. Kubota, G. E. W. Bauer, K. Takanashi

    PHYSICAL REVIEW MATERIALS　2　(9)　094404-1-094404-7　2018/09

    DOI： 10.1103/PhysRevMaterials.2.094404 　

    ISSN： 2475-9953

  75. Relationship between anomalous Ettingshausen effect and anomalous Nernst effect in an FePt thin film Peer-reviewed

    T. Seki, R. Iguchi, K. Takanashi, K. Uchida

    Journal of Physics D: Applied Physics　51　(25)　254001-1-254001-6　2018/05/30

    DOI： 10.1088/1361-6463/aac481 　

    ISSN： 0022-3727

    eISSN： 1361-6463

  76. Visualization of anomalous Ettingshausen effect in a ferromagnetic film: Direct evidence of different symmetry from spin Peltier effect Peer-reviewed

    T. Seki, R. Iguchi, K. Takanashi, K. Uchida

    Applied Physics Letters　112　(15)　152403-1-152403-5　2018/04

    DOI： 10.1063/1.5022759 　

    ISSN： 0003-6951

  77. Size dependence of vortex-type spin torque oscillation in a Co2Fe0.4Mn0.6Si Heusler alloy disk Peer-reviewed

    T. Seki, T. Kubota, T. Yamamoto, K. Takanashi

    Journal of Physics D: Applied Physics　51　075005-1-075005-7　2018/01

  78. Magnetoelastic Properties of Epitaxially Grown Co2Fe0.4Mn0.6Si and Co2FeGa0.5Ge0.5 Heusler Alloys Thin Films Peer-reviewed

    O. M. Chumak, A. Nabiałek, R. Zuberek, I. Radelytskyi, T. Yamamoto, T. Seki, K. Takanashi, L. T. Baczewski, H. Szymczak

    IEEE Transactions on Magnetics　53　2501906-1-2501906-6　2017/11

    DOI： 10.1109/TMAG.2017.2700790 　

  79. Magnetic anisotropy of L10-ordered FePt thin films studied by Fe and Pt L2,3-edges x-ray magnetic circular dichroism Peer-reviewed

    K. Ikeda, T. Seki, G. Shibata, T. Kadono, K. Ishigami, Y. Takahashi, M. Horio, S. Sakamoto, Y. Nonaka, M. Sakamaki, K. Amemiya, N. Kawamura, M. Suzuki, K. Takanashi, A. Fujimori

    Applied Physics Letters　111　142402-1-142402-5　2017/10/02

    DOI： 10.1063/1.4993077 　

  80. Nonlinear electric field effect on perpendicular magnetic anisotropy in Fe/MgO interfaces Peer-reviewed

    Q. Xiang, Z. Wen, H. Sukegawa, S. Kasai, T. Seki, T. Kubota, K. Takanashi, S. Mitani

    Journal of Physics D: Applied Physics　50　40LT04-1-40LT04-5　2017/09/14

  81. Magnetization switching behavior of exchange-coupled bilayer nanodots characterized by magneto-optical Kerr effect Peer-reviewed

    W. Zhou, T. Seki, K. Takanashi

    Journal of Applied Physics　122　093902-1-093902-5　2017/09/01

    DOI： 10.1063/1.4985848 　

  82. Electric field effect on magnetic anisotropy for Fe-Pt-Pd alloys Peer-reviewed

    S. Kikushima, T. Seki, K. Uchida, E. Saitoh, K. Takanashi

    AIP Advances　7　085210-1-085210-7　2017/08/11

  83. Magnetic Anisotropy and Damping for Monolayer-Controlled Co | Ni Epitaxial Multilayer Peer-reviewed

    Takeshi Seki, Junpei Shimada, Satoshi Iihama, Masahito Tsujikawa, Tomoyuki Koganezawa, Akihiro Shioda, Takayuki Tashiro, Weinan Zhou, Shigemi Mizukami, Masafumi Shirai, Koki Takanashi

    Journal of the Physical Society of Japan　86　074710-1-074710-8　2017/06/22

  84. Role of the Cr Buffer Layer in the Thickness-Dependent Ultrafast Magnetization Dynamics of Co2Fe0.4Mn0.6Si Heusler Alloy Thin Films Peer-reviewed

    S. Pan, T. Seki, K. Takanashi, A. Barman

    Physical Review Applied　7　064012-1-064012-8　2017/06/12

  85. Control of Magnetization Dynamics in Ordered Alloy Systems Invited Peer-reviewed

    T. Seki, W. Zhou, T. Yamamoto, K. Takanashi

    Journal of the Magnetics Society of Japan　41　(3)　46-51　2017/06

    DOI： 10.3379/msjmag.1704R001 　

  86. Capturing ultrafast magnetic dynamics by time-resolved soft x-ray magnetic circular dichroism Peer-reviewed

    Kou Takubo, Kohei Yamamoto, Yasuyuki Hirata, Yuichi Yokoyama, Yuya Kubota, Shingo Yamamoto, Susumu Yamamoto, Iwao Matsuda, Shik Shin, Takeshi Seki, Koki Takanashi, Hiroki Wadati

    Applied Physics Letters　110　162401-1-162401-5　2017/04/20

    DOI： 10.1063/1.4981769 　

  87. Voltage control of magnetic anisotropy in epitaxial Ru/Co2FeAl/ MgO heterostructures Peer-reviewed

    Z. Wen, H. Sukegawa, T. Seki, T. Kubota, K. Takanashi, S. Mitani

    Scientific Reports　7　45026-1-45026-8　2017/03/23

  88. Resonant magnetization switching conditions of an exchange-coupled bilayer under spin wave excitation Peer-reviewed

    W. Zhou, T. Yamaji, T. Seki, H. Imamura, K. Takanashi

    Applied Physics Letters　110　082401-1-082401-5　2017/02/22

    DOI： 10.1063/1.4976707 　

  89. Vortex-dynamics-mediated low-field magnetization switching in an exchange-coupled system Peer-reviewed

    W. Zhou, T. Seki, H. Arai, H. Imamura, K. Takanashi

    Physical Review B　94　220401R-1-220401R-5　2016/12/08

    DOI： 10.1103/PhysRevB.94.220401 　

  90. Influence of thickness-dependent structural evolution on ultrafast magnetization dynamics in Co2Fe0.4Mn0.6Si Heusler alloy thin films Peer-reviewed

    S. Pan, S. Mondal, T. Seki, K. Takanashi, A. Barman

    Physical Review B　94　184417-1-184417-8　2016/11/15

    DOI： 10.1103/PhysRevB.94.184417 　

  91. Structural and Magnetic Properties of MBE Grown (Fe/Pt) (111) Multilayers Peer-reviewed

    A. Marynowska, E. Dynowska, S. Lewinska, T. Seki, K. Takanashi, J. Kanak, A. Pietruczik, P. Aleszkiewicz, A. Wawro, A. Slawska-Waniewsk, L.T. Baczewski

    ACTA PHYSICA POLONICA A　130　1363-1370　2016/10/18

  92. Vortex spin-torque oscillator using Co2FexMn1−xSi Heusler alloys Peer-reviewed

    T. Yamamoto, T. Seki, K. Takanashi

    Physical Review B　94　094419-1-094419-9　2016/09/16

    DOI： 10.1103/PhysRevB.94.094419 　

  93. Magnetoresistance effect in Fe20Ni80/graphene/Fe20Ni80 vertical spin valves Peer-reviewed

    S. Entani, T. Seki, Y. Sakuraba, T. Yamamoto, S. Takahashi, H. Naramoto, K. Takanashi, S. Sakai

    Applied Physics Letters　109　082406-1-082406-5　2016/08/26

    DOI： 10.1063/1.4961669 　

  94. Magnetic vortex in epitaxially-grown Co2(Fe,Mn)Si alloy Peer-reviewed

    T. Yamamoto, T. Seki, M. Kotsugi, K. Takanashi

    Applied Physics Letters　108　152402-1-152402-5　2016/04/11

    DOI： 10.1063/1.4945730 　

  95. Enhancement of electric field modulation of coercivity in Pt / Co / Al-O structures by tuning Co surface oxidation Peer-reviewed

    J. Shiogai, T. Ohashi, T. Yang, M. Kohda, T. Seki, K. Takanashi, J. Nitta

    J. Phys. D: Appl. Phys.　49　03LT01-1-03LT01-5　2016/01

    DOI： 10.1088/0022-3727/49/3/03LT01 　

  96. Resonant switching for an in-plane magnetized L10-FePt | Ni81Fe19 bilayer under spin wave excitation Peer-reviewed

    T. Seki, W. Zhou, K. Takanashi

    J. Phys. D: Appl. Phys.　49　075002-1-075002-10　2016/01

    DOI： 10.1088/0022-3727/49/7/075002 　

  97. Magnetostriction Measurements of L10 Fe50Pt(50–x)Pdx Thin Films Peer-reviewed

    W. Li, W. Zhou, P. Lenox, T. Seki, K. Takanashi, A. Jander, P. Dhagat

    IEEE Trans. Magn.　51　2504904-1-2504904-4　2015/11

    DOI： 10.1109/TMAG.2015.2450755 　

  98. Superferromagnetism in dipolarly coupled L10 FePt nanodots with perpendicular magnetization Peer-reviewed

    S. Bedanta, T. Seki, H. Iwama, T. Shima, K. Takanashi

    Applied Physics Letters　107　152410-1-152410-4　2015/10

    DOI： 10.1063/1.4933381 　

  99. Roadmap for Emerging Materials for Spintronic Device Applications Peer-reviewed

    A. Hirohata, H. Sukegawa, H. Yanagihara, I. Žutić, T. Seki, S. Mizukami, R. Swaminathan

    IEEE Trans. Magn.　51　0800511-1-0800511-11　2015/10

    DOI： 10.1109/TMAG.2015.2457393 　

  100. Enhancement of anomalous Nernst effects in metallic multilayers free from proximity-induced magnetism Peer-reviewed

    Ken Ichi Uchida, Takashi Kikkawa, Takeshi Seki, Takafumi Oyake, Junichiro Shiomi, Zhiyong Qiu, Koki Takanashi, Eiji Saitoh

    Physical Review B - Condensed Matter and Materials Physics　92　(9)　094414-1-094414-6　2015/09/10

    DOI： 10.1103/PhysRevB.92.094414 　

    ISSN： 1098-0121

    eISSN： 1550-235X

  101. Observation of inverse spin Hall effect in ferromagnetic FePt alloys using spin Seebeck effect Peer-reviewed

    Takeshi Seki, Ken Ichi Uchida, Takashi Kikkawa, Zhiyong Qiu, Eiji Saitoh, Koki Takanashi

    Applied Physics Letters　107　(9)　092401-1-092401-4　2015/08/31

    DOI： 10.1063/1.4929691 　

    ISSN： 0003-6951

  102. Comparison of electrical and optical detection of spin injection in L10-FePt/MgO/GaAs hybrid structures Peer-reviewed

    R. Ohsugi, J. Shiogai, Y. Kunihashi, M. Kohda, H. Sanada, T. Seki, M. Mizuguchi, H. Gotoh, K. Takanashi, J. Nitta

    J. Phys. D: Appl. Phys.　48　164003-1-164003-5　2015/04

    DOI： 10.1088/0022-3727/48/16/164003 　

  103. Spin torque-induced magnetization dynamics in giant magnetoresistance devices with Heusler alloy layers Peer-reviewed

    T. Seki, H. Yako, T. Yamamoto, T. Kubota, Y. Sakuraba, K. Takanashi

    J. Phys. D: Appl. Phys.　48　164010-1-164010-8　2015/04

    DOI： 10.1088/0022-3727/48/16/164010 　

  104. Zero-field spin torque oscillation in Co2(Fe, Mn)Si with a point contact geometry Peer-reviewed

    T. Yamamoto, T. Seki, T. Kubota, H. Yako, K. Takanashi

    Applied Physics Letters　106　092406-1-092406-5　2015/03

    DOI： 10.1063/1.4914375 　

  105. Layer thickness dependence of spin orbit torques and fields in Pt/Co/AlO trilayer structures Peer-reviewed

    T. Yang, M. Kong, M. Kohda, T. Seki, K. Takanashi, J. Nitta

    Japanese Journal of Applied Physics　54　04DM05-1-04DM05-6　2015/03

    DOI： 10.7567/JJAP.54.04DM05 　

  106. Interface magnetic anisotropy for monatomic layer-controlled Co/Ni epitaxial multilayers Peer-reviewed

    A. Shioda, T. Seki, J. Shimada, K. Takanashi

    Journal of Applied Physics　117　17C726-1-17C726-4　2015/03

    DOI： 10.1063/1.4915106 　

  107. Perpendicularly magnetized L10-FePt nanodots exchange-coupled with soft magnetic Ni81Fe19 Peer-reviewed

    W. Zhou, T. Seki, H. Iwama, T. Shima, K. Takanashi

    Journal of Applied Physics　117　013905-1-013905-6　2015/01

    DOI： 10.1063/1.4905302 　

  108. Magnetic domain imaging in L10 ordered FePt thin films with in-plane uniaxial magnetic anisotropy Peer-reviewed

    S. Mallick, S. Bedanta, T. Seki, K. Takanashi

    J. Appl. Phys.　116　133904-1-133904-6　2014/10

    DOI： 10.1063/1.4897243 　

  109. Perpendicular magnetic anisotropy in Pt/Co/AlO trilayer structures depending on AlO thickness and fabrication method Peer-reviewed

    T. Yang, M. Kohda, T. Seki, K. Takanashi, J. Nitta

    Key Eng. Mater.　616　247-251　2014/09

    DOI： 10.4028/www.scientific.net/KEM.616.247 　

  110. High Power All-Metal Spin Torque Oscillator Using Full Heusler Co2(Fe,Mn)Si Peer-reviewed

    T. Seki, Y. Sakuraba, H. Arai, M. Ueda, R. Okura, H. Imamura, K. Takanashi

    Applied Physics Letters　105　092406-1-092406-5　2014/09

    DOI： 10.1063/1.4895024 　

  111. Linewidth broadening of optical precession mode in synthetic antiferromagnet Peer-reviewed

    K. Tanaka, T. Moriyama, M. Nagata, T. Seki, K. Takanashi, S. Takahashi, T. Ono

    Applied Physics Express　7　063010-1-063010-4　2014/06

    DOI： 10.7567/APEX.7.063010 　

  112. Current-induced spin polarization on metal surfaces probed by spin-polarized positron beam Peer-reviewed

    H. J. Zhang, S. Yamamoto, Y. Fukaya, M. Maekawa, H. Li, A. Kawasuso, T. Seki, E. Saitoh, K. Takanashi

    Scientific Reports　4　4844-1-4844-5　2014/04

    DOI： 10.1038/srep04844 　

  113. Observation and suppression of quantized spin waves in microfabricated permalloy elements Peer-reviewed

    T. Yamamoto, T. Seki, S. Ono, K. Takanashi

    Japanese Journal of Applied Physics　53　04EM01-1-04EM01-4　2014/02

    DOI： 10.7567/JJAP.53.04EM01 　

  114. Platinum layer thickness dependence of spin-Hall induced effective magnetic field in Pt/Co/Pt structures Peer-reviewed

    T. Yang, M. Kohda, T. Seki, K. Takanashi, J. Nitta

    Japanese Journal of Applied Physics　53　04EM06-1-04EM06-5　2014/02

    DOI： 10.7567/JJAP.53.04EM06 　

  115. Characterization of spin pumping effect in Permalloy/Cu/Pt microfabricated lateral devices Peer-reviewed

    T. Yamamoto, T. Seki, S. Ono, K. Takanashi

    Journal of Applied Physics　115　17C505-1-17C505-3　2014/01

    DOI： 10.1063/1.4861681 　

  116. Magnetization damping of an L10-FeNi thin film with perpendicular magnetic anisotropy Peer-reviewed

    M. Ogiwara, S. Iihama, T. Seki, T. Kojima, S. Mizukami, M. Mizuguchi, K. Takanashi

    Applied Physics Letters　103　242409-1-242409-5　2013/12

    DOI： 10.1063/1.4845035 　

  117. Magnetic Nanoparticles: A Subject for Both Fundamental Research and Applications (Review Article) Peer-reviewed

    S. Bedanta, A. Barman, W. Kleemann, O. Petracic, T. Seki

    Journal of Nanomaterials　2013　952540-1-952540-22　2013/12

  118. Characteristic field angular dependence of magnetization switching assisted by spin wave excitation Peer-reviewed

    T. Seki, K. Hotta, H. Imamura, Y. Nozaki, K. Takanashi

    Applied Physics Letters　103　122403-1-122403-4　2013/09

    DOI： 10.1063/1.4821208 　

  119. Voltage-induced coercivity change in FePt/MgO stacks with different FePt thicknesses Peer-reviewed

    Y. Kikuchi, T. Seki, M. Kohda, J. Nitta, K. Takanashi

    J. Phys. D: Appl. Phys.　46　285002-1-285002-6　2013/06

    DOI： 10.1088/0022-3727/46/28/285002 　

  120. Characterization of MgO Thin Films Grown on Carbon Materials by Molecular Beam Epitaxy Peer-reviewed

    S. Kobayashi, S. Miwa, F. Bonell, S. Yoshikuni, T. Seki, M. Shiraishi, T. Shinjo, N. Mizuoch, Y. Suzuki

    Jpn. J. Appl. Phys. (Rapid communication)　52　070208-1-070208-3　2013/06

    DOI： 10.7567/JJAP.52.070208 　

  121. Spin Wave-Assisted Reduction in Switching Field of Highly Coercive Iron-Platinum Magnets Peer-reviewed

    T. Seki, K. Utsumiya, Y. Nozaki, H. Imamura, K. Takanashi

    Nature Communications　4　1726-1-1726-6　2013/04/16

    DOI： 10.1038/ncomms2737 　

  122. Current-induced spin polarization on a Pt surface: A new approach using spin-polarized positron annihilation spectroscopy Peer-reviewed

    A. Kawasuso, Y. Fukaya, M. Maekawa, H. Zhang, T. Seki, T. Yoshino, E. Saitoh, K. Takanashi

    J. Magn. Magn. Mater.　342　139-143　2013/04

    DOI： 10.1016/j.jmmm.2013.04.006 　

  123. High power radio frequency oscillation by spin transfer torque in a Co2MnSi layer: Experiment and macrospin simulation Peer-reviewed

    T. Seki, Y. Sakuraba, R. Okura, K. Takanashi

    J. Appl. Phys.　113　033907-1-033907-6　2013/01

    DOI： 10.1063/1.4776719 　

  124. Simple Analysis for Frequency Increase in Spin Torque Oscillation Peer-reviewed

    C. Mitsumata, S. Tomita, T. Seki, M. Mizuguchi

    IEEE Trans. Magn.　48　3955-3957　2012/11

    DOI： 10.1109/TMAG.2012.2201700 　

  125. Interface Magnetic Anisotropy Between L10-FePt and Nonmagnetic Layers Peer-reviewed

    T. Seki, Y. Kikuchi, K. Takanashi

    IEEE Trans. Magn.　48　3199-3202　2012/11

    DOI： 10.1109/TMAG.2012.2194272 　

  126. MgO Layer Thickness Dependence of Structure and Magnetic Properties of L10-FePt/MgO/GaAs Structures Peer-reviewed

    R. Osugi, M. Kohda, T. Seki, A. Ohtsu, M. Mizuguchi, K. Takanashi, J. Nitta

    Japanese Journal of Applied Physics　51　02BM05-1-02BM05-4　2012/02

    DOI： 10.1143/JJAP.51.02BM05 　

  127. Optical pump and probe measurements of the magnetization dynamics in antiferromagnetically coupled layers Peer-reviewed

    H. Tomita, A. R. Khorsand, T. Seki, A. Kirilyuk, A. Kimel, T. Rasing, Y. Suzuki

    Journal of the Magnetics Society of Japan　36　24-27　2012

    DOI： 10.3379/msjmag.1108M003 　

  128. Magnetic properties of L10-FePt / permalloy exchange-spring films Peer-reviewed

    K. Utsumiya, T. Seki, K. Takanashi

    Journal of Applied Physics　110　103911-1-103911-6　2011/11

    DOI： 10.1063/1.3662901 　

  129. High Spin-Torque Diode Sensitivity in CoFeB/MgO/CoFeB Magnetic Tunnel Junctions Under DC Bias Currents Peer-reviewed

    S. Ishibashi, K. Ando, T. Seki, T. Nozaki, H. Kubota, S. Yakata, H. Maehara, A. Fukushima, S. Yuasa, Y. Suzuki

    IEEE Transactions on Magnetics　47　3373-3376　2011/10

    DOI： 10.1109/TMAG.2011.2159830 　

  130. Size dependence of the magnetizationreversal process in microfabricated L10-FePt nano dots Peer-reviewed

    T. Seki, H. Iwama, T. Shima, K. Takanashi

    Journal of Physics D: Applied Physics　44　335001-1-335001-10　2011/08

    DOI： 10.1088/0022-3727/44/33/335001 　

  131. High-power rf oscillation induced in half-metallic Co2MnSi layer by spin-transfer torque Peer-reviewed

    R. Okura, Y. Sakuraba, T. Seki, K. Izumi, M. Mizuguchi, K. Takanashi

    Applied Physics Letters　99　052510-1-052510-3　2011/08

    DOI： 10.1063/1.3624470 　

  132. High-speed spin-transfer switching in GMR nano-pillars with perpendicular anisotropy Peer-reviewed

    H. Tomita, T. Nozaki, T. Seki, T. Nagase, K. Nishiyama, E. Kitagawa, M. Yoshikawa, T. Daibou, M. Nagamine, T. Kishi, S. Ikegawa, N. Shimomura, H. Yoda, Y. Suzuki

    IEEE Transactions on Magnetics　47　1599-1602　2011/06

    DOI： 10.1109/TMAG.2011.2105860 　

  133. Coercivity change in an FePt thin layer in a Hall device by voltage application Peer-reviewed

    T. Seki, M. Kohda, J. Nitta, K. Takanashi

    Applied Physics Letters　98　212505-1-212505-3　2011/05

    DOI： 10.1063/1.3595318 　

  134. Spin-torque induced rf oscillation in magnetic tunnel junctions with an Fe-­rich CoFeB free layer Peer-reviewed

    Y. Masugata, S. Ishibashi, H. Tomita, T. Seki, T. Nozaki, Y. Suzuki, H. Kubota, A. Fukushima, S. Yuasa

    J. Phys: Conf. Series　266　012098-1-012098-6　2011/01

    DOI： 10.1088/1742-6596/266/1/012098 　

  135. Surface-Assisted Spin Hall effect in Au films with Pt impurities Peer-reviewed

    B. Gu, I. Sugai, T. Ziman, G. Y. Guo, N. Nagaosa, T. Seki, K. Takanashi, S. Maekawa

    Phys. Rev. Lett.　105　216401-1-216401-1　2010/11

    DOI： 10.1103/PhysRevLett.105.216401 　

  136. rf auto-oscillations in antiferromagnetically coupled layers with different coupling strengths Peer-reviewed

    T. Seki, H. Tomita, T. Shinjo, Y. Suzuki

    Applied Physics Letters　97　162508-1-162508-3　2010/10

    DOI： 10.1063/1.3505357 　

  137. Large diode sensitivity of CoFeB/MgO/CoFeB magnetic tunnel junctions Peer-reviewed

    S. Ishibashi, T. Seki, T. Nozaki, H. Kubota, S. Yakata, A. Fukushima, S. Yuasa, H. Maehara, K. Tsunekawa, D. D. Djayaprawira, Y. Suzuki

    Applied Physics Express　3　073001-1-073001-3　2010/06

    DOI： 10.1143/APEX.3.073001 　

  138. Spin-transfer-torque-induced rf oscillation in CoFeB/MgO/CoFeB magnetic tunnel junctions under a perpendicular magnetic field Peer-reviewed

    T. Wada, T. Yamane, T. Seki, T. Nozaki, Y. Suzuki, H. Kubota, A. Fukushima, S. Yuasa, H. Maehara, Y. Nagamine, K. Tsunekawa, D. D. Djayaprawira, N. Watanabe

    Physical Review B　81　104410-1-104410-7　2010/03

    DOI： 10.1103/PhysRevB.81.104410 　

  139. Coupled-mode excitations induced in an antiferromagnetically coupled multilayer by spin-transfer torque Peer-reviewed

    T. Seki, H. Tomita, M. Shiraishi, T. Shinjo, Y. Suzuki

    Applied Physics Express　3　033001-1-033001-3　2010/02

    DOI： 10.1143/APEX.3.033001 　

  140. Spin Hall effect and Nernst effect in FePt/Au multi-terminal devices with different Au thicknesses Peer-reviewed

    T. Seki, I. Sugai, Y. Hasegawa, S. Mitani, K. Takanashi

    Solid State Communications　150　496-499　2010

    DOI： 10.1016/j.ssc.2009.11.018 　

  141. Microwave-assisted magnetization reversal in a perpendicular magnetized film Peer-reviewed

    T. Yoshioka, T. Nozaki, T. Seki, M. Shiraishi, T. Shinjo, Y. Suzuki, Y. Uehara

    Applied Physics Express　3　013002-1-013002-3　2010/01

    DOI： 10.1143/APEX.3.013002 　

  142. Field orientation dependence of spin-torque-induced rf oscillations in magnetic tunnel junctions Peer-reviewed

    T. Wada, T. Yamane, T. Seki, T. Nozaki, Y. Suzuki, H. Kubota, A. Fukushima, S. Yuasa, H. Maehara, Y. Nagamine, K. Tsunekawa, D. D. Djayaprawira, N. Watanabe

    Journal of the Magnetics Society of Japan　33　(4)　379-383　2009/05

    DOI： 10.3379/msjmag.0905RE0002 　

  143. Spin-transfer-torque-induced ferromagnetic resonance for Fe/Cr/Fe layers with an antiferromagnetic coupling field Peer-reviewed

    T. Seki, H. Tomita, A. A. Tulapurkar, M. Shiraishi, T. Shinjo, Y. Suzuki

    Applied Physics Letters　94　212505-1-212505-3　2009/05

    DOI： 10.1063/1.3143625 　

  144. Phenomenological analysis of magnetization reversal process for L10-FePt (001) particulate films Peer-reviewed

    D. Wang, T. Seki, K. Takanashi, T. Shima, G. Q. Li, H. Saito, S. Ishio

    Journal of Applied Physics　105　07A702-1-07A702-3　2009/02

    DOI： 10.1063/1.3058615 　

  145. Dot size dependence of magnetization reversal process in L10-FePt dot arrays Peer-reviewed

    D. Wang, T. Seki, K. Takanashi, T. Shima, G. Q. Li, H. Saito, S. Ishio

    IEEE Transactions on Magnetics　44　3464-3467　2008/11

    DOI： 10.1109/TMAG.2008.2002503 　

  146. Magnetization reversal process in microfabricated L10-FePt dots Peer-reviewed

    D. Wang, T. Seki, K. Takanashi, T. Shima

    Journal of Physics D: Applied Physics　41　195008-1-195008-6　2008/09

    DOI： 10.1088/0022-3727/41/19/195008 　

  147. Nucleation-type magnetization reversal by spin-polarized current in perpendicularly magnetized FePt layers Peer-reviewed

    T. Seki, S. Mitani, K. Takanashi

    Physical Review B　77　214414-1-214414-8　2008/06

    DOI： 10.1103/PhysRevB.77.214414 　

  148. High remanent magnetization of L10 ordered FePt thin film on MgO / (001) GaAs Peer-reviewed

    M. Kohda, A. Ohtsu, T. Seki, A. Fujita, J. Nitta, S. Mitani, K. Takanashi

    Japanese Journal of Applied Physics　47　3269-3271　2008/04

    DOI： 10.1143/JJAP.47.3269 　

  149. Giant spin Hall effect in perpendicularly spin-polarized FePt/Au devices Peer-reviewed

    T. Seki, Y. Hasegawa, S. Mitani, S. Takahashi, H. Imamura, S. Maekawa, J. Nitta, K. Takanashi

    Nature Materials　7　125-129　2008/01

    DOI： 10.1038/nmat2098 　

  150. Magnetic bubbles in FePt nanodots with perpendicular anisotropy Peer-reviewed

    C. Moutafis, S. Komineas, C. A. F. Vaz, J. A. C. Bland, T. Shima, T. Seki, K. Takanashi

    Physical Review B　76　104426-1-104426-5　2007/09

    DOI： 10.1103/PhysRevB.76.104426 　

  151. Epitaxial growth of L10-FePt / MgO / L10-FePt (001) trilayer structures Peer-reviewed

    M. Hagiuda, S. Mitani, T. Seki, K. Yakushiji, T. Shima, K. Takanashi

    Journal of Magnetism and Magnetic Materials　310　1905-1906　2007

    DOI： 10.1016/j.jmmm.2006.10.877 　

  152. Magnetization reversal by spin-transfer torque in 90º configuration with a perpendicular spin polarizer Peer-reviewed

    T. Seki, S. Mitani, K. Yakushiji, K. Takanashi

    Applied Physics Letters　89　172504-1-172504-3　2006/10

    DOI： 10.1063/1.2369648 　

  153. Dot size dependence of magnetic properties in microfabricated L10-FePt (001) and L10-FePt (110) dot arrays Peer-reviewed

    T. Seki, T. Shima, K. Yakushiji, K. Takanashi, G. Q. Li, S. Ishio

    Journal of Applied Physics　100　043915-1-043915-8　2006/08

    DOI： 10.1063/1.2335391 　

  154. Spin-polarized current-induced magnetization reversal in perpendicularly magnetized L10-FePt layers Peer-reviewed

    T. Seki, S. Mitani, K. Yakushiji, K. Takanashi

    Applied Physics Letters　88　172504-1-172504-3　2006/04

    DOI： 10.1063/1.2198819 　

  155. Magnetization switching in nanopillars with FePt alloys by spin-polarized current Peer-reviewed

    T. Seki, S. Mitani, K. Yakushiji, K. Takanashi

    Journal of Applied Physics　99　08G521-1-08G521-3　2006/04

    DOI： 10.1063/1.2176064 　

  156. Domain wall resistance in FePt wire with perpendicular magnetic anisotropy Peer-reviewed

    H. Tanigawa, A. Yamaguchi, S. Kasai, T. Ono, T. Seki, T. Shima, K. Takanashi

    Journal of Applied Physics　99　08G520-1-08G520-3　2006/04

    DOI： 10.1063/1.2170038 　

  157. Improvement of hard magnetic properties in microfabricated L10-FePt dot arrays upon post-annealing Peer-reviewed

    T. Seki, T. Shima, K. Yakushiji, K. Takanashi, G. Q. Li, S. Ishio

    IEEE Transactions on Magnetics　41　3604-3606　2005/10

    DOI： 10.1109/TMAG.2005.854787 　

  158. Fabrication and characterization of L10-ordered FePt / AlO / FeCo magnetic tunnel junctions Peer-reviewed

    S. Mitani, K. Tsukamoto, T. Seki, T. Shima, K. Takanashi

    IEEE Transactions on Magnetics　41　2606-2608　2005/10

    DOI： 10.1109/TMAG.2005.854718 　

  159. Influence of the buffer layers on magnetic properties of FePt (001) films sputter-deposited at reduced temperature Peer-reviewed

    T. Seki, T. Shima, K. Takanashi, Y. Takahashi, E. Matsubara, Y. K. Takahashi, K. Hono

    Journal of Applied Physics　96　1127-1132　2004/07

    DOI： 10.1063/1.1763000 　

  160. Optimum composition for the low-temperature fabrication of highly ordered FePt (001) and FePt (110) films Peer-reviewed

    T. Seki, T. Shima, K. Takanashi, Y. Takahashi, E. Matsubara, K. Hono

    IEEE Transactions on Magnetics　40　2522-2524　2004/06

    DOI： 10.1109/TMAG.2004.832108 　

  161. Magnetic tunnel junctions with L10-ordered FePt alloy electrodes Peer-reviewed

    T. Moriyama, S. Mitani, T. Seki, T. Shima, K. Takanashi, A. Sakuma

    Journal of Applied Physics　95　6789-6791　2004/06

    DOI： 10.1063/1.1669212 　

  162. Magneto-optical spectra of ordered and disordered FePt films prepared at reduced temperature Peer-reviewed

    K. Sato, A. Mizusawa, K. Ishida, T. Seki, T. Shima, K. Takanashi

    Trans. Magn. Soc. Japan　4　297-300　2004

    DOI： 10.3379/tmjpn2001.4.297 　

  163. Magnetic properties of FePt (001) films with a variety of compositions sputter-deposited at reduced temperature Peer-reviewed

    T. Seki, T. Shima, K. Takanashi

    Trans. Magn. Soc. Japan　4　190-193　2004

    DOI： 10.3379/tmjpn2001.4.190 　

  164. Fabrication of in-plane magnetized FePt sputtered films with large uniaxial anisotropy Peer-reviewed

    T. Seki, T. Shima, K. Takanashi

    Journal of Magnetism and Magnetic Materials　272-276　2182-2183　2004

    DOI： 10.1016/j.jmmm.2003.12.912 　

  165. Fabrication of L10 ordered FePt thin films with a canted easy magnetization axis on MgO (110) substrates Peer-reviewed

    T. Shima, T. Seki, K. Takanashi, Y. K. Takahashi, K. Hono

    Journal of Magnetism and Magnetic Materials　272-276　e557-e559　2004

    DOI： 10.1016/j.jmmm.2003.11.322 　

  166. L10 ordering of off-stoichiometric FePt (001) thin films at reduced temperature Peer-reviewed

    T. Seki, T. Shima, K. Takanashi, Y. Takahashi, E. Matsubara, K. Hono

    Applied Physics Letters　82　2461-2463　2003/04

    DOI： 10.1063/1.1567053 　

  167. Fabrication of L10 ordered FePt thin films by monatomic layer sputter-deposition Peer-reviewed

    T. Shima, T. Moriguchi, T. Seki, S. Mitani, K. Takanashi

    Journal of Applied Physics　93　7238-7240　2003

    DOI： 10.1063/1.1555363 　

Show all ︎Show first 5

Misc. 23

  1. 薄膜の垂直磁気異方性 Invited Peer-reviewed

    高梨弘毅, 関剛斎

    まぐね　19　100-106　2024/06

  2. 新しいエネルギー変換技術としての磁気熱電効果：異常ネルンスト効果 Invited Peer-reviewed

    関剛斎

    電気学会誌　143　710-713　2023/11

  3. 反強磁性結合人工格子の新展開 –反対称層間交換結合を中心にして– Invited Peer-reviewed

    関剛斎, 増田啓人, 高梨弘毅

    固体物理　58　9-20　2023/05

  4. Recent Progress and Issues for Materials Enabling Interconversion between Electric Current, Spin Current, and Heat Current Invited Peer-reviewed

    Takeshi Seki

    Materia Japan　62　(2)　85-92　2023/02/01

    Publisher: Japan Institute of Metals

    DOI： 10.2320/materia.62.85 　

    ISSN： 1340-2625

    eISSN： 1884-5843

  5. 金属人工格子ルネサンス Peer-reviewed

    高梨弘毅, 関剛斎

    まぐね　17　(1)　4-11　2022/01

  6. Interface Effects in Spin Caloritronics Peer-reviewed

    Ken-ichi UCHIDA, Takeshi SEKI

    Vacuum and Surface Science　64　(12)　562-567　2021/12/10

    Publisher: Surface Science Society Japan

    DOI： 10.1380/vss.64.562 　

    ISSN： 2433-5835

    eISSN： 2433-5843

  7. 異常エッチングスハウゼン効果：磁気熱電効果がもたらす新しい熱制御機能 Invited

    関剛斎, 内田健一

    電気学会誌　139　(10)　662-667　2019

  8. スピントロニクス材料の進展 -規則合金を中心にして- Invited

    高梨弘毅, 関剛斎, 窪田崇秀, 伊藤啓太

    機能材料　38　(8)　48-58　2018/08

  9. 磁気ボルテックスダイナミクスを利用した交換結合膜における磁化スイッチング

    関剛斎, 周偉男, 高梨弘毅

    IEICE Technical Report　117　1-4　2017/06/08

  10. ホイスラー合金を用いたスピントルク発振素子の現状と課題

    関剛斎, 山本竜也, 周偉男, 高梨弘毅

    応用電子物性分科会誌　22　125-128　2016/11/21

    Publisher: 応用物理学会

  11. ホイスラー合金を用いたスピントルク発振

    関剛斎, 山本竜也, 高梨弘毅

    日本磁気学会第208回研究会資料　51-56　2016/06/09

    Publisher: 日本磁気学会

  12. スピン波励起を利用した低磁場磁化反転

    関剛, 周偉男, 高梨弘毅

    まぐね　10　314-319　2015/12

  13. 規則合金スピントロニクス材料の最近の発展

    窪田崇秀, 関剛斎, 水口将輝, 高梨弘毅

    電気学会研究会資料　MAG-15-129-133　MAG-15-130-5-MAG-15-130-8　2015/12

  14. スピン波を利用した磁化スイッチング

    関剛斎, 高梨弘毅

    応用物理　84　61-65　2015/01

  15. 高い磁気異方性を有するL10型FePtおよびL10型FeNi規則合金薄膜

    小嶋隆幸, 関剛斎, 水口将輝, 高梨弘毅

    セラミックス　48　404-409　2013/05

  16. 高保磁力FePt合金の磁化制御

    関剛斎

    まてりあ　51　216-220　2012/05

    DOI： 10.2320/materia.51.216 　

  17. 電界およびスピン波を用いたFePt規則合金薄膜の磁化制御

    関剛斎, 菊池祐介, 堀田京子, 高梨弘毅

    応用電子物性分科会誌　18　176-179　2012

  18. FePt垂直スピン注入源を用いたAuにおける巨大スピンホール効果

    関剛斎, 菅井勇, 三谷誠司, 高梨弘毅

    電子情報通信学会技術研究報告　110　(225)　71-76　2010

  19. MgO-MTJおよびCPP-GMRにおけるスピントルク発振 ~発振の高出力化および高周波化にむけて~

    関剛斎, 和田朋之, 冨田博之, 山根健量, 升方康智, A. A. Tulapurkar, 野崎隆行, 白石誠司, 新庄輝也, 鈴木義茂, 久保田均, 福島章雄, 湯浅新治, 前原大樹, 永峰佳紀, 恒川孝二, D, D. Djayaprawira, 渡辺直樹

    日本応用磁気学会第168回研究会　23-27　2009

  20. 金属系における巨大スピンホール効果

    関剛斎, 三谷誠司, 高梨弘毅, 高橋三郎, 前川禎通

    固体物理　43　(12)　903-910　2008/12

  21. FePt垂直スピン注入源を用いたAuの巨大スピンホール効果

    関剛斎, 長谷川裕, 三谷誠司, 高梨弘毅

    まぐね　3　(10)　467-473　2008/10

  22. L10 FePtナノ構造エピタキシャル薄膜の磁化過程

    高梨弘毅, 嶋敏之, 関剛斎

    日本応用磁気学会第146回研究会　33-40　2006

  23. 非化学量論組成FePt合金膜におけるL10規則相の低温合成と磁気特性

    嶋敏之, 関剛斎, 高梨弘毅

    日本応用磁気学会誌　28　(4)　501-507　2004/04

Show all ︎Show first 5

Books and Other Publications 6

  1. Spintronics Handbook -Fundamentals and Applications-

    2023/05

  2. Nanomagnetic materials : fabrication, characterization and application

    Takeshi Seki, Koki Takanashi

    Elsevier　2021/07/13

    ISBN: 0128223499

  3. Novel Structured Metallic and Inorganic Materials

    Takahide Kubota, Takeshi Seki, Koki Takanashi

    Springer　2019

  4. 薄膜の評価技術ハンドブック

    高梨弘毅, 関剛斎

    株式会社テクノシステム　2013

  5. スピントロニクスの基礎と材料・応用技術の最前線

    関剛斎, 高梨弘毅

    シーエムシー出版　2009/06

  6. Epitaxial Ferromagnetic Films and Spintronic Applications

    T. Seki, S. Mitani, K. Takanashi

    2009

Show all Show first 5

Presentations 158

  1. 人工反強磁性構造における反対称交換相互作用の薄膜成長条件依存性

    関剛斎, 増田啓人, クシュワハ ヴァルン, 山崎匠, 伊藤啓太

    日本金属学会2025年春期講演大会　2025/03/09

  2. Control of Magneto-Elasticity in Magnetic Thin Films

    Takeshi Seki, Keita Ito

    Summit of Materials Science 2024 and GIMRT User Meeting 2024　2024/11/28

  3. Control of Magneto-Elasticity in Magnetic Thin Films Invited

    Takeshi Seki, Keita Ito

    REIMEI International workshop: Physics of Advanced Functional Materials　2024/10/10

  4. Giant tunability of magnetoelasticity in Fe4N system Invited

    Takeshi Seki, Keita Ito

    The 5th International Symposium on Advanced Magnetic Materials and Applications (ISAMMA)　2024/08/06

  5. Synthetic Antiferromagnet-based Spintronics

    Takeshi Seki

    The 34th Joint Inter-laboratory Workshop on Nano-magnetics　2024/02/22

  6. Metallic Superlattices Revisited Invited

    Koki Takanashi, Takeshi Seki

    Annual meeting of the Physical Society of Taiwan (TPS2024),Taiwan-Japan Joint Symposium　2024/01/25

  7. Metallic Superlattices Revisited Invited

    Koki Takanashi, Takeshi Seki

    MRM 2023 / IUMRS-ICA 2023　2023/12/14

  8. Magneto-Thermoelectric Conversion in Metallic Superlattices

    Takeshi Seki

    Summit of Materials Science 2023 and GIMRT User Meeting 2023　2023/11/21

  9. Large Antisymmetric Interlayer Exchange Coupling in Synthetic Antiferromagnet Invited

    Takeshi Seki, H. Masuda, K. Takanashi

    11th International Symposium on Metallic Multilayers　2023/07/27

  10. Enhanced Anomalous Nernst Effect in Metallic Superlattices Invited

    Takeshi Seki

    The 4th Workshop on Functional Materials Science　2023/06/20

  11. High Spin-Charge Conversion Efficiency of Co3Sn2S2 Promoted by Transition from Paramagnetic to Ferromagnetic Phase

    Takeshi Seki, Yong-Chang Lau, Junya Ikeda, Kohei Fujiwara, Akihiro Ozawa, Satoshi Iihama, Kentaro Nomura, Atsushi Tsukazaki

    Intermag 2023　2023/05/19

  12. 人工反強磁性体におけるスピン軌道トルク Invited

    関 剛斎

    「スピントロニクス学術研究基盤と連携ネットワーク（Spin-RNJ）」シンポジウム/Spin-RNJ 2022年度報告会　2023/03/21

  13. Temperature Dependence of Spin-Charge Conversion Efficiency for Co3Sn2S2 Thin Film

    Takeshi Seki, Yong-Chang Lau, Junya Ikeda, Kohei Fujiwara, Akihiro Ozawa, Satoshi Iihama, Kentaro Nomura, Atsushi Tsukazaki

    第70回応用物理学会 春季学術講演会　2023/03/16

  14. Antisymmetric interlayer exchange coupling in synthetic antiferromagnet Invited

    T. Seki

    York-Tohoku-Kaiserslautern-Leeds-Manchester-Spintech Symposium　2022/12/06

  15. 人工反強磁性体における反対称層間交換結合 Invited

    関 剛斎

    令和4年電気学会 基礎・材料・共通部門大会　2022/09/13

  16. Co3Sn2S2化合物における強磁性転移によるスピン変換効率の増大

    関剛斎, Y.-C. Lau, 池田絢哉, 藤原宏平, 飯浜賢志, 小沢耀弘, 野村健太郎, 塚﨑敦

    第46回日本磁気学会学術講演会　2022/09/08

  17. 強磁性転移に伴うスピン変換効率の増大 Invited

    関 剛斎

    令和5年東北大学電気通信研究所・共同プロジェクト研究会「スピン・軌道・多極子がもたらす新規界面物性の開拓」　2022/06/19

  18. Enhanced Anomalous Nernst Effect in Metallic Superlattices Invited

    T. Seki, K. Takanashi

    DALIAN UNIVERSITY OF TECHNOLOGY - TOHOKU UNIVERSITY JOINT WORKSHOP ON ADVANCED MATERIALS　2022/05/23

  19. 電流−スピン流−熱流変換のための材料創製 Invited

    関剛斎

    日本金属学会2022年春期講演大会　2022/03/17

  20. Large antisymmetric interlayer exchange coupling Invited

    T. Seki, H. Masuda, K. Takanashi

    Indo-Japan Workshop on Interface Phenomena for Spintronics (IJW-IPS) 2022　2022/03/08

  21. 人工反強磁性体における反対称交換相互作用 Invited

    関剛斎, 増田啓人, 高梨弘毅

    令和4年東北大学電気通信研究所・共同プロジェクト研究会「固体中のスピン・軌道ダイナミクスとその制御」　2022/01/28

  22. Spin-Charge Conversion in Ferromagnetic Materials Invited

    T. Seki

    Symposium on magnetism and spintronics (SMS-1) 2021　2021/11/27

  23. Spin-orbit torque in a Ni-Fe single layer

    T. Seki, Y.-C. Lau, S. Iihama, K. Takanashi

    2021/09/10

  24. Ni-Fe単層膜におけるスピン軌道トルク

    関剛斎, Y.-C. Lau, 飯浜賢志, 高梨弘毅

    第45回日本磁気学会学術講演会　2021/09/01

  25. Development of Cu-based spin Hall materials Invited

    T. Seki, H. Masuda, K. Takanashi

    SPIE. OPTICS + PHOTONICS, Spintronics XIV　2021/08/01

  26. Origin and Optical Switching of Perpendicular Magnetization for Co100-xGdx/Pt Multilayers

    T. Seki, J. Wang, Y.-C. Lau, Y. K. Takahashi, K. Takanashi

    Intermag 2021　2021/04/26

  27. 金属人工格子における磁気熱電効果 Invited

    関剛斎

    ナノスケール磁性体を用いた機能性材料開発調査専門委員会・研究会　2021/04/02

  28. Origin and Optical Switching of Perpendicular Magnetization for Co100-xGdx/Pt Multilayers

    T. Seki, J. Wang, Y.-C. Lau, Y. K. Takahashi, K. Takanashi

    2021/03/17

  29. Origin and Optical Switching of Perpendicular Magnetization for Co-Gd/Pt Multilayers Invited

    Takeshi Seki

    Tohoku-Lorraine Joint Conference　2021/03/03

  30. Development of Cu-based Spin Hall Materials Invited

    T. Seki, H. Masuda, K. Takanashi

    The 4th International Symposium for The Core Research Cluster for Spintronics　2021/02/25

  31. Cu基2元系合金を用いた層間交換結合とスピンホール効果 Invited

    関剛斎, 増田啓人, 高梨弘毅

    電気学会 マグネティックス技術委員会, 光・熱・電気との相互作用を活用した高機能磁気デバイス技術調査専門委員会　2020/12/18

  32. Enhanced anomalous Nernst effect in Ni / Pt superlattice

    T. Seki, Y. Sakuraba, A. Miura, K. Masuda, M. Tsujikawa, K. Uchida, T. Kubota, Y. Miura, M. Shirai, K. Takanashi

    65th Annual Conference on Magnetism and Magnetic Materials (Virtual Form)　2020/11/05

  33. Cu-based spin Hall materials -Antiferromagnetic spintronics & Non-equilibrium alloy- Invited

    T. Seki

    Webinar series on Spintronics　2020/09/17

  34. Enhanced anomalous Nernst effect in Ni / Pt superlattice

    T. Seki, Y. Sakuraba, A. Miura, K. Masuda, M. Tsujikawa, K. Uchida, T. Kubota, Y. Miura, M. Shirai, K. Takanashi

    2020/09/10

  35. Large spin anomalous Hall effect in L10-FePt Invited

    T. Seki

    SPIE. OPTICS + PHOTONICS, Spintronics XIII　2020/08/20

  36. Magnetization Dynamics and Switching in Exchange-Coupled Systems Invited

    T. Seki, K. Takanashi

    International Workshop on Exchange Driven Magnetization Dynamics　2020/07/23

  37. Artificial Antiferromagnetic Layered Structure with Cu-Ir “Spin Hall” Spacer Layer Invited

    T. Seki, H. Masuda, K. Takanashi

    The 60th REIMEI International Workshop "New excitations for spintronics seen with quantum beams"　2020/02/28

  38. Spin-Charge Conversion in Ferromagnets Invited

    T. Seki, K. Takanashi

    The 3rd Symposium for The Core Research Clusters for Materials Science and Spintronics　2020/02/10

  39. Spin-Charge Conversion in Ferromagnetic Materials Invited

    T. Seki, K. Takanashi

    New Perspective in Spin Conversion Science (NPSCS2020)　2020/02/04

  40. Large Spin Anomalous Hall Effect in L10-FePt

    T. Seki, S. Iihama, T. Taniguchi, K. Takanashi

    Materials Research Meeting 2019 (MRM2019)　2019/12/11

  41. Spin-Charge Conversion in Ferromagnetic Materials Invited

    T. Seki, K. Takanashi

    17th RIEC International Workshop on Spintronics and 10th JSPS Core-to-Core Workshop on “New-Concept Spintronic Devices”　2019/12/05

  42. Spin-Charge Conversion in Ferromagnetic Materials International-presentation

    T. Seki, K. Takanashi

    PSI-KINKEN Joint Symposium 2019　2019/10/29

  43. L10-FePtにおけるスピン異常ホール効果

    関剛斎, 飯浜賢志, 谷口知大, 高梨弘毅

    第43回日本磁気学会学術講演会　2019/09/25

  44. 垂直磁化Ni/Pt金属人工格子

    関剛斎, 野尻英史, 窪田崇秀, 伊藤啓太, 紅林秀和, 内田健一, 桜庭裕弥, 三浦飛鳥, 辻川雅人, 白井正文, 高梨弘毅

    日本金属学会2019年秋期大会　2019/09/12

  45. Perpendicularly Magnetized Ni / Pt Superlattices International-presentation

    T. Seki, T. Kubota, K. Ito, H. Kurebayashi, K. Uchida, Y. Sakuraba, A. Miura, M. Tsujikawa, M. Shirai, K. Takanashi

    MML 2019　2019/05/19

  46. Anomalous Ettingshausen Effect in Ferrimagnetic Co-Gd

    T. Seki, A. Miura, K. Uchida, T. Kubota, K. Takanashi

    2019/03/10

  47. Spin Anomalous Hall Effect in L10-FePt

    T. Seki, S. Iihama, T. Taniguchi, K. Takanashi

    The 2nd Symposium for World Leading Research Centers　2019/02/16

  48. Visualization of thermo-magnetic effect in a ferromagnetic thin film International-presentation Invited

    T. Seki, R. Iguchi, K. Takanashi, K. Uchida

    International Conference on Magnetic Materials and Applications (ICMAGMA-2018)　2018/12/11

  49. Visualization of thermo-magnetic effect in a ferromagnetic FePt thin film

    T. Seki, R. Iguchi, K. Takanashi, K. Uchida

    Summit of Materials Science 2018　2018/10/30

  50. 強磁性およびフェリ磁性物質における熱磁気効果の可視化 Invited

    関剛斎

    ナノスピン放射光科学研究会「放射光を用いたナノスピン材料科学の新展開」　2018/10/05

  51. フェリ磁性金属／非磁性金属の積層構造におけるスピンホール磁気抵抗効果

    関剛斎, 周偉男, 窪田崇秀, バウアーゲーリット, 高梨弘毅

    日本金属学会2018年秋期大会　2018/09/19

  52. FePt 薄膜における異常エッティングスハウゼン効果の可視化

    関剛斎, 井口亮, 高梨弘毅, 内田健一

    第42回日本磁気学会学術講演会　2018/09/11

  53. Spin-Hall Magnetoresistance in Pt / Co-Gd / Cr Layers International-presentation

    T. Seki, W. Zhou, T. Kubota, K. Takanashi

    23rd International Colloquium on Magnetic Films and Surfaces　2018/07/24

  54. Spin-hall magnetoresistance in ferrimagnetic Co-Gd / nonmagnetic Pt layers Invited

    T. Seki, W. Zhou, T. Kubota, G. E. W. Bauer, K. Takanashi

    KINKEN-KIST Joint Symposium 2018　2018/07/05

  55. Anomalous Ettingshausen Effect in a Ferromagnetic FePt Thin Film International-presentation Invited

    T. Seki, R. Iguchi, K. Takanashi, K. Uchida

    5th International Conference of Asian Union of Magnetics Societies (IcAUMS)　2018/06/06

  56. Spin-hall Magnetoresistance for Cr / Co100-xGdx / Pt Layered Structures International-presentation

    T. Seki, W. Zhou, T. Kubota, K. Takanashi

    5th International Conference of Asian Union of Magnetics Societies (IcAUMS)　2018/06/06

  57. Size Dependence of Vortex Dynamics in a Co2(Fe,Mn)Si Heusler Alloy Disk International-presentation

    T. Seki, T. Kubota, T. Yamamoto, K. Takanashi

    5th International Conference of Asian Union of Magnetics Societies (IcAUMS)　2018/06/06

  58. Spin-Hall and Anisotropic Magnetoresistance Effects in Layered Structures with Ferrimagnetic Co-Gd Alloys International-presentation

    T. Seki, W. Zhou, T. Kubota, K. Takanashi

    INTERMAG 2018　2018/04/24

  59. Spin-Hall and anisotropic magnetoresistance in Pt / ferrimagnetic Co-Gd / Cr layers

    T. Seki, W. Zhou, T. Kubota, K. Takanashi

    2018/03/19

  60. Observation of Anomalous Ettingshausen Effect in a Ferromagnetic FePt Thin Film International-presentation Invited

    T. Seki, R. Iguchi, K. Takanashi, K. Uchida

    Reimei/GP-Spin/ICC-IMR International Workshop "New Excitations in Spintronics”　2018/01/10

  61. Visualization of Anomalous Ettingshausen Effect in a Ferromagnetic Film International-presentation Invited

    T. Seki, R. Iguchi, K. Takanashi, K. Uchida

    Tohoku / York / Kaiserslautern, 6th JSPS Core-to-Core Workshop　2017/12/15

  62. Thermal Imaging of Anomalous Ettingshausen Effect in a Ferromagnetic Thin Film International-presentation Invited

    T. Seki, R. Iguchi, K. Takanashi, K. Uchida

    Tohoku University-KIST joint symposium　2017/11/21

  63. Spin Torque Vortex Oscillator Using Heusler Alloy Layers International-presentation Invited

    T. Seki, K. Takanashi

    IUMRS-ICA 2017　2017/11/08

  64. Magnetization Switching Assisted by Spin Wave Dynamics

    K. Takanashi

    第41回日本磁気学会学術講演会　2017/09/19

  65. Thermal Imaging of Anomalous Ettingshausen Effect in a Ferromagnetic Thin Film

    R. Iguchi, K. Takanashi, K. Uchida

    新学術領域「ナノスピン変換」平成29年度スピン変換研究会　2017/09/11

  66. 規則合金をベースとしたスピントロニクス材料研究の現状と課題

    東京大学物性研究所 第7回量子物質・ナノスケールセミナー　2017/06/16

  67. 磁気ボルテックスダイナミクスを利用した交換結合膜における磁化スイッチング

    周偉男, 高梨弘毅

    磁気記録・情報ストレージ研究会（MR）・マルチメディアストレージ研究会（ITE-MMS）　2017/06/08

  68. ホイスラー合金ディスクにおける磁気構造と動的挙動

    第15 回SPring-8ユーザー協同体顕微ナノ材料科学研究会・第12 回日本表面科学会放射光表面科学研究部会 合同シンポジウム　2017/03/02

  69. スピントルク発振型磁場センサのための要素技術開発

    ミニシンポジウム：生命科学量子技術・ナノエレ・生命科学研究の融合　2017/02/28

  70. スピン波を利用した交換結合膜における共鳴スイッチング

    周偉男, 高梨弘毅

    東北大学電気通信研究所 共同プロジェクト研究会　2017/01/31

  71. ホイスラー合金を用いたスピントルク発振素子の現状と課題

    山本竜也, 周偉男, 高梨弘毅

    応用電子物性分科会・スピントロニクス研究会 共催研究会　2016/11/21

  72. Spin dynamics in ordered alloy systems and its application to spintronic devices International-presentation

    W. Zhou, T. Yamamoto, K. Takanashi

    KINKEN-KIST joint seminar "Future electronic materials and devices beyond Si"　2016/10/24

  73. Spin Hall effect in ferromagnetic FePt alloy International-presentation

    K. Uchida, T. Kikkawa, Z. Qiu, E. Saitoh, K. Takanashi

    International workshop on nano-spin conversion science & quantum spin dynamics (NSCS-QSD)　2016/10/12

  74. 原子層積層制御したCo/Niエピタキシャル人工格子における磁気特性

    島田淳平, 飯浜賢志, 辻川雅人, 小金澤智之, 田代敬之, 周偉男, 菊池直登, 水上成美, 白井正文, 高梨弘毅

    日本金属学会2016年秋期大会　2016/09/21

  75. Co/Niエピタキシャル人工格子における磁気異方性とダンピング

    島田淳平, 飯浜賢志, 辻川雅人, 小金澤智之, 塩田明弘, 田代敬之, 周偉男, 菊池直登, 水上成美, 白井正文, 高梨弘毅

    第40回日本磁気学会学術講演会　2016/09/05

  76. Spin dynamics in ordered alloy systems and its application to spintronic devices International-presentation

    K. Takanashi

    The 9th Pacific Rim International Conference on Advanced Materials and Processing　2016/08/01

  77. Magnetization Switching in Exchange-Coupled Systems International-presentation

    W. Zhou, K. Takanashi

    4th International Conference of Asian Union of Magnetics Societies (ICAUMS)　2016/08/01

  78. Spin Torque Oscillation in Co-based Heusler Alloy International-presentation

    T. Yamamoto, K. Takanashi

    3rd Workshop of the Core-to-Core Project Tohoku-York-Kaiserslautern, Kaiserslautern　2016/06/22

  79. ホイスラー合金を用いたスピントルク発振

    日本磁気学会第208回研究会　2016/06/09

  80. ホイスラー合金における磁気ボルテックスの制御とスピントルク発振

    山本竜也, 小嗣真人, 高梨弘毅

    日本物理学会第71回年次大会　2016/03/19

  81. Magnetic Vortex Formation and Its Dynamics for Co-Based Heusler Alloys International-presentation

    T. Yamamoto, K. Takanashi

    13th Joint MMM-Intermag Conference　2016/01/11

  82. Vortex Dynamics-Mediated Magnetization Switching in L10-FePt | Ni81Fe19 Nanodots International-presentation

    W. Zhou, H. Arai, H. Imamura, K. Takanashi

    13th Joint MMM-Intermag Conference　2016/01/11

  83. 規則合金におけるスピンダイナミクスの制御と機能創出

    東北大学電気通信研究所 共同プロジェクト研究(S) 研究会「スピントロニクス学術研究基盤と連携ネットワーク」構築に向けて　2015/12/05

  84. Magnetization switching in hard magnet triggered by exchange-coupled soft magnet International-presentation

    W. Zhou, K. Takanashi

    JSPS Core-to-Core Workshop on New-Concept Spintronics Devices　2015/11/12

  85. Formation and Dynamics of Magnetic Vortex in Co-Based Heusler Alloys

    T. Yamamoto, K. Takanashi

    第76回応用物理学会秋季学術講演会　2015/09/13

  86. 垂直磁化FePt | Ni81Fe19ナノドットにおける磁気渦ダイナミクスを介した磁化反転

    周偉男, 今村裕志, 荒井礼子, 高梨弘毅

    第39回日本磁気学会学術講演会　2015/09/08

  87. Spin wave dynamics for microfabricated elements with exchange-coupled bilayers International-presentation

    W. Zhou, K. Takanashi

    22nd International Colloquium on Magnetic Films and Surfaces　2015/07/12

  88. Voltage control of magnetic properties in FePt-based ultrathin films International-presentation

    S. Kikushima, W. Zhou, K. Takanashi

    The 1st 【ImPACT】 Inter'l Symposium on Spintronic Memory Circuit and Storage　2015/06/21

  89. Electric field control of magnetization switching in ordered alloy systems International-presentation

    1st French and Japanese joint workshop on electric field effect　2015/06/18

  90. Point-Contact Spin Torque Oscillators Using Highly Spin-Polarized Heusler Alloys International-presentation

    T. Yamamoto, T. Kubota, H. Yako, K. Takanashi

    Intermag 2015　2015/05/11

  91. Magnetocrystalline Anisotropy in Co2(FexMn1-x)Si Heusler Thin Films

    T. Yamamoto, T. Kubota, K. Takanashi

    第62回応用物理学会春季学術講演会　2015/03/11

  92. Spin Torque Oscillators with Highly Spin-Polarized Heusler Alloy International-presentation

    T. Yamamoto, K. Takanashi

    APS March Meeting 2014　2015/03/02

  93. High Power All-Metal Spin Torque Oscillators International-presentation

    K. Takanashi

    Indo Japan Workshop on Magnetism at Nanoscale　2015/01/09

  94. Spin Wave-Assisted Magnetization Switching in Nanometer-Scaled Bilayer Elements International-presentation

    W. Zhou, K. Takanashi

    Solid State Devices and Materials (SSDM) 2014　2014/09/08

  95. Co2(Fe,Mn)Si合金を用いた高出力スピントルク発振素子

    桜庭裕弥, 荒井礼子, 今村裕志, 高梨弘毅

    第38回日本磁気学会学術講演会　2014/09/02

  96. Magnetization switching induced by spin wave excitation International-presentation

    K. Takanashi

    IUMRS-ICA 2014　2014/08/24

  97. High Power rf Oscillation Induced by Spin Torque in a Co2(Fe,Mn)Si Layer International-presentation

    Y. Sakuraba, M. Ueda, R. Okura, K. Takanashi, H. Arai, H. Imamura

    Intermag 2014　2014/05/04

  98. High Power Spin Torque Oscillation in a Co2(Fe,Mn)Si Layer

    Y. Sakuraba, M. Ueda, R. Okura, K. Takanashi, H. Arai, H. Imamura

    第61回応用物理学会春季学術講演会　2014/03/17

  99. Spin Wave Dynamics and Magnetization Switching in Exchange-Coupled Bilayers International-presentation

    APS March Meeting 2014　2014/03/03

  100. Magnetization switching assisted by spin wave International-presentation

    K. Takanashi

    Magnetics and Optics Research International Symposium (MORIS 2013)　2013/12/02

  101. Magnetization Switching in L10-FePt Using Spin Waves with Large Oscillation Amplitude International-presentation

    K. Hotta, K. Takanashi

    58th Annual conference on Magnetism & Magnetic Materials　2013/11/04

  102. Magnetization Damping of an L10-FeNi Thin Film with Perpendicular Magnetic Anisotropy International-presentation

    M. Ogiwara, S. Iihama, T. Kojima, S. Mizukami, M. Mizuguchi, K. Takanashi

    58th Annual conference on Magnetism & Magnetic Materials　2013/11/04

  103. Spin wave-assisted switching in L10-FePt/permalloy bilayers

    K. Takanashi

    第37回 日本磁気学会学術講演会　2013/09/03

  104. Magnetization Switching Assisted by Spin Wave Excitation International-presentation

    K. Takanashi

    The 3rd International Symposium on Advanced Magnetic Materials and Applications (ISAMMA 2013)　2013/07/21

  105. High Power Spin Torque Oscillation in a Co2MnSi Layer International-presentation

    Y. Sakuraba, R. Okura, K. Takanashi

    The 3rd International Symposium on Advanced Magnetic Materials and Applications (ISAMMA 2013)　2013/07/21

  106. Magnetization Switching in Hard Magnetic FePt - from Switching Mechanisms to Spin Wave Assistance International-presentation

    Summer School and Annual Meeting on Advanced Spintronic Materials and Transport Phenomena　2013/07/01

  107. Voltage-induced coercivity change in L10-FePt / MgO stacks with various FePt thicknesses International-presentation

    Y. Kikuchi, M. Kohda, J. Nitta, K. Takanashi

    MML 2013　2013/05/19

  108. スピン波アシスト磁化反転における磁化ダイナミクス

    堀田京子, 能崎幸雄, 今村裕志, 高梨弘毅

    第60回応用物理学会春季学術講演会　2013/03/27

  109. スピン波励起による磁化反転と放射光ナノビーム解析の展望

    H24年度GIGNO研究領域創成支援プロジェクトワークショップ　2013/03/12

  110. Magnetization switching assisted by spin wave excitation International-presentation

    International Workshop on Development of Functionalized Molecule-based Magnetic Materials　2013/02/18

  111. Spin wave-assisted magnetization switching International-presentation

    SMS 2012 (Summit of Materials Science)　2012/11/27

  112. 電界およびスピン波を用いたFePt規則合金薄膜の磁化制御

    関剛斎, 菊池祐介, 堀田京子, 高梨弘毅

    応用電子物性分科会・スピントロニクス研究会共催研究会　2012/11/21

  113. Spin wave-assisted magnetization switching International-presentation

    K. Utsumiya, Y. Nozaki, H. Imamura, K. Takanashi

    International Conference of AUMS　2012/10/02

  114. Control of Magnetization Switching in Highly Coercive L10-FePt International-presentation

    K. Takanashi

    21st International Colloquium on Magnetic Films and Surfaces　2012/09/24

  115. L10型FePt規則合金における低エネルギー磁化反転

    日本金属学会2012年秋期大会　2012/09/17

  116. Control of Magnetization Reversal in Hard Magnetic L10-FePt International-presentation

    K. Takanashi

    IUMRS-ICYRAM 2012　2012/07/01

  117. FePt規則合金の磁化反転制御

    第19回「みちのく磁性談話会」　2012/06/02

  118. Geometrical dependence of spin-Hall signal in lateral devices with a perpendicular spin polarizer International-presentation

    T. Seki, S. Shibata, K. Takanashi

    Intermag 2012　2012/05/07

  119. スピン波アシスト磁化反転

    関剛斎, 宇津宮和寿, 能崎幸雄, 今村裕志, 高梨弘毅

    日本物理学会第67回年次大会　2012/03/24

  120. スピン波アシスト磁化反転

    関剛斎, 宇津宮和寿, 能崎幸雄, 今村裕志, 高梨弘毅

    第59回応用物理学関係連合講演会　2012/03/15

  121. 高保磁力FePt薄膜における磁化制御

    関剛斎, 高梨弘毅

    第44回ナノマグネティックス専門研究会　2011/12/02

  122. Control of Magnetization Switching in L10-FePt International-presentation

    T. Seki, K. Takanashi

    International Symposium of GCOE: Materials Integration in conjunction with The 2nd International Symposium on Advanced Synthesis and Processing Technology for Materials (ASPT2011)　2011/12/01

  123. L10型FePt規則合金を用いたスピン流生成と磁化制御

    関剛斎, 高梨弘毅

    応用物理学会スピントロニクス研究会・日本磁気学会スピンエレクトロニクス専門研究会　2011/11/14

  124. Coercivity Change in an FePt Thin Layer by Voltage Application International-presentation

    T. Seki, M. Kohda, J. Nitta, K. Takanashi

    56th Annual conference on Magnetism & Magnetic Materials　2011/10/30

  125. 人工制御ねじれ磁気構造の強磁性共鳴測定

    関剛斎, 宇津宮和寿, 高梨弘毅

    第35回日本磁気学会学術講演会　2011/09/26

  126. FePt 薄膜における電圧印加保磁力制御

    関剛斎, 好田誠, 新田淳作, 高梨弘毅

    第35回日本磁気学会学術講演会　2011/09/26

  127. FePt薄膜における電圧印加保磁力変調

    関剛斎, 好田誠, 新田淳作, 高梨弘毅

    物理学会2011年秋季大会　2011/09/21

  128. FePt薄膜における磁気特性の電圧制御

    関剛斎, 好田誠, 新田淳作, 高梨弘毅

    第72回応用物理学会学術講演会　2011/08/29

  129. Voltage-Induced Coercivity Change of a FePt Thin Layer in a Hall Device International-presentation

    T. Seki, M. Kohda, J. Nitta, K. Takanashi

    5th International Workshop on Spin Currents　2011/07/25

  130. Giant spin-Hall effect in doped Au International-presentation

    T. Seki, I. Sugai, S. Shibata, S. Mitani, K. Takanashi

    5th International Workshop on Spin Currents　2011/07/25

  131. Ferromagnetic resonance for twisted spin structures in in-plane magnetized FePt / Permalloy bilayers International-presentation

    T. Seki, K. Utsumiya, K. Takanashi

    Intermag 2011　2011/04/25

  132. 人工制御ねじれ磁気構造の強磁性共鳴測定

    関剛斎, 宇津宮和寿, 高梨弘毅

    第66回日本物理学会年次大会　2011/03/25

  133. Magnetization Reversal Process in Nanometer-Sized FePt Dots International-presentation

    T. Seki, K. Takanashi

    International Conference of AUMS　2010/12/05

  134. FePt垂直スピン注入源を用いたAuにおける巨大スピンホール効果

    関剛斎, 菅井勇, 三谷誠司, 高梨弘毅

    第37回ナノマグネティクス専門研究会　2010/10/14

  135. RF AUTO-OSCILLATION IN ANTIFERROMAGNETICALLY-COUPLED LAYERS International-presentation

    T. Seki, H. Tomita, M. Shiraishi, T. Shinjo, Y. Suzuki

    IEEE MML 2010　2010/09/19

  136. 数10nmサイズFePt円形ドットの磁気特性

    関剛斎, 高梨弘毅

    第34回日本磁気学会学術講演会　2010/09/04

  137. RF Auto-Oscillation in Antiferromagnetically-Coupled Layers by Spin-Transfer Torque International-presentation

    T. Seki, H. Tomita, M. Shiraishi, T. Shinjo, Y. Suzuki

    International Symposium on Advanced Magnetic Materials and Applications 2010　2010/07/12

  138. Spin-transfer-torque-induced rf oscillation for antiferromagnetically-coupled Fe/Cr/Fe layers International-presentation

    T. Seki, H. Tomita, M. Shiraishi, T. Shinjo, Y. Suzuki

    11th Joint MMM-Intermag Conference　2010/01/18

  139. Spin-transfer-torque-induced rf oscillation for Fe/Cr/Fe layers with an antiferromagnetic coupling field International-presentation

    T. Seki, H. Tomita, T. Yamane, M. Shiraishi, T. Shinjo, Y. Suzuki

    International Conference on Solid State Devices and Materials　2009/10

  140. Spin-transfer induced spin excitation in an antiferromagnetically-coupled nanomagnet International-presentation

    4th International Symposium on Medical, Bio- and Nano-Electronics　2009/03/05

  141. Giant spin Hall effect in perpendicularly spin-polarized FePt/Au devices International-presentation

    Intermag 2008　2008/05/04

  142. Electrical detection of giant spin Hall effects in perpendicularly spin-polarized FePt/Au multi-terminal devices International-presentation

    International Workshop on Spin Currents　2008/02/18

  143. Room temperature spin Hall effect in perpendicularly spin-polarized FePt/Au devices International-presentation

    T. Seki, Y. Hasegawa, S. Mitani, K. Takanashi, S. Takahashi, S. Maekawa, H. Imamura, J. Nitta

    52th Annual conference on Magnetism & Magnetic Materials　2007/11/05

  144. Direct and inverse spin Hall effects in FePt/Au lateral structures. International-presentation

    T. Seki, Y. Hasegawa, S. Mitani, S. Takahashi, H. Imamura, S. Maekawa, J. Nitta, K. Takanashi

    IEEE MML 2007　2007/10/15

  145. Magnetic field dependence of current-induced magnetization reversal with perpendicularly magnetized FePt layers. International-presentation

    T. Seki, S. Mitani, K. Takanashi

    The 1st International Symposium on Advanced Magnetic Materials　2007/05/28

  146. Spin transfer torque from a FePt perpendicular spin polarizer on an in-plane magnetized layer International-presentation

    T. Seki, S. Mitani, K. Yakushiji, K. Takanashi

    International Workshop on Spin Transfer　2006/10/02

  147. Current-induced magnetization reversal in FePt nanostructures International-presentation

    The 3rd Asia forum on Magnetics　2006/09/11

  148. Current-induced magnetization reversal in perpendicularly magnetized FePt layers. International-presentation

    T. Seki, S. Mitani, K. Yakushiji, K. Takanashi

    International Conference on Magnetism 2006　2006/08/20

  149. Current-induced magnetization reversal in FePt nanopillars with perpendicular magnetization. International-presentation

    T. Seki, S. Mitani, K. Yakushiji, K. Takanashi

    19th International Colloquium on Magnetic Films and Surfaces　2006/08/14

  150. Magnetization reversal in perpendicularly magnetized FePt layers by spin-polarized current. International-presentation

    T. Seki, S. Mitani, K. Yakushiji, K. Takanashi

    MORIS 2006 Workshop　2006/06/06

  151. Current induced magnetization reversal in epitaxially grown FePt / Au / FePt nanopillars. International-presentation

    T. Seki, S. Mitani, K. Yakushiji, K. Takanashi

    50th Annual conference on Magnetism & Magnetic Materials　2005/10/30

  152. Current-perpendicular-to-plane giant magnetoresistance in FePt / Au layered structures International-presentation

    T. Seki, S. Mitani, K. Yakushiji, T. Shima, K. Takanashi

    Intermag 2005　2005/04/04

  153. Magnetic properties in epitaxial L10 FePt dot arrays International-presentation

    T. Seki, T. Shima, K. Yakushiji, K. Takanashi, G. Q. Li, S. Ishio

    Intermag 2005　2005/04/04

  154. Magnetic properties for dot arrays of epitaxially grown FePt ordered alloy International-presentation

    T. Seki, T. Shima, K. Yakushiji, K. Takanashi, G. Q. Li, S. Ishio

    49th Annual conference on Magnetism & Magnetic Materials　2004/11/07

  155. Magnetic properties of FePt (001) films with a variety of buffer layers grown at reduced temperature International-presentation

    T. Seki, T. Shima, K. Takanashi, Y. Takahashi, E. Matsubara, Y. K. Takahasni, K. Hono

    MORIS 2004　2004/05/16

  156. Composition dependence of structure and magnetic properties for FePt (001) films sputtered-deposited at reduced temperature International-presentation

    T. Seki, T. Shima, K. Takanashi, Y. Takahashi, E. Matsubara, K. Hono

    The 8th IUMRS International Conference on Advance Materials　2003/10/08

  157. Fabrication of in-plane magnetized FePt sputtered films with large uniaxial anisotropy International-presentation

    T. Seki, T. Shima, K. Takanashi

    International Conference on Magnetism 2006　2003/07/27

  158. L10 ordering of off-stoichiometric FePt (001) thin films at reduced temperature International-presentation

    T. Seki, T. Shima, K. Takanashi, Y. Takahashi, E. Matsubara, K. Hono

    18th International Colloquium on Magnetic Films and Surfaces　2003/07/22

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Industrial Property Rights 11

  1. 磁性材料、積層体及び積層体の製造方法並びに熱電変換素子及び磁気センサ

    王建, 関剛斎, 高梨弘毅

    特許7628700

    Property Type: Patent

  2. 磁気メモリ素子及び該磁気メモリ素子に用いる磁性材料

    森山貴広, 小野輝男, 関剛斎, 周偉男, 高梨弘毅

    Property Type: Patent

  3. 磁性薄膜および磁性薄膜の製造方法

    関剛斎, 高梨弘毅, 辻川雅人, 白井正文

    Property Type: Patent

  4. マイクロ波アシスト磁気記録媒体、マイクロ波アシスト磁気記録媒体の製造方法及びマイクロ波アシスト磁化反転方法

    関剛斎, 高梨弘毅, 周偉男, 荒井礼子, 今村裕志

    Property Type: Patent

  5. 磁気センサ素子及び磁気センサ

    関剛斎, 高梨弘毅, 山本竜也

    Property Type: Patent

  6. トランジスタおよびその製造方法

    好田誠, 永沼博, 関剛斎, 遠藤恭, 宮崎孝道

    Property Type: Patent

  7. マイクロ波アシスト磁気記録媒体

    関剛斎, 高梨弘毅

    5927627

    Property Type: Patent

  8. マイクロ波素子

    前原大樹, 鈴木義茂, 関剛斎, 升方康智, 石橋翔太, 久保田均

    Property Type: Patent

  9. スピン伝導素子

    佐々木智生, 及川亨, 田上勝通, 関剛斎

    Property Type: Patent

  10. 磁気素子及び集積回路並びに磁気ランダムアクセスメモリ

    三谷誠司, 高梨弘毅, 関剛斎

    Property Type: Patent

  11. 垂直磁気異方性を有するFePt磁性薄膜とその製造方法

    関剛斎, 嶋敏之, 高梨弘毅, 宝野和博

    3981732

    Property Type: Patent

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Other 7

  1. 規則合金を基軸としたナノ磁性金属複合体における磁化ダイナミクス制御

    More details Close

    規則合金を基軸としたナノ磁性金属複合体における磁化ダイナミクス制御に関する研究

  2. 反強磁性界面におけるスピントルクの創出と制御

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    反強磁性界面におけるスピントルクの創出と制御を行う研究

  3. 磁性規則合金を用いた新機能性スピントルク発振素子の創製

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    異なる金属原子が規則的に空間配列した規則合金を用いると、無秩序合金には無い機能性を発現させることが可能となります。本研究では、ホイスラー合金という磁性規則合金を材料の軸とし、磁気渦(ボルテックス)構造とその動的挙動を制御することで、高速応答かつ高集積可能な超高感度スピントルク発振型磁気素子の実現に取り組みます。そして、新しい動作原理に基づく磁気センサの基盤技術の構築を目指します。

  4. 垂直型ねじれ磁気構造の作製と磁化ダイナミクスの解明

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    垂直型ねじれ磁気構造を有する磁性複合膜の作製と、その磁気構造における磁化ダイナミクスの解明に関する研究

  5. 空間変調磁気構造を用いた低消費エネルギー磁化反転技術の開発

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    空間変調磁気構造を用いた低消費エネルギー磁化反転技術の開発に関する研究

  6. 高磁気異方性材料における電圧印加磁化制御技術の開発

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    高磁気異方性材料における電圧印加磁化制御技術の開発に関する研究

  7. 高保磁力FePtナノ構造体における磁気特性の電界制御

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    本研究事業では、高保磁力FePt規則合金のナノ構造体に電圧を印加することによって、その磁気特性を電界制御することを目的としている。電界を用いた磁化方向制御は消費電力をゼロに近づけることが可能な手法であり、磁気記憶デバイスの低消費電力化のためのキーテクノロジーになると期待できる。

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