Updated on 2024/09/17

写真a

 
KOMORI Sachio
 
Organization
Graduate School of Science Assistant Professor
Graduate School
Graduate School of Science
Undergraduate School
School of Science Department of Physics
Title
Assistant Professor

Degree 1

  1. 博士(工学) ( 2016.3   京都大学 ) 

Awards 3

  1. The Japan Society of Applied Physics Superconductors Division Research Award

    2024.3   The Japan Society of Applied Physics  

  2. Young Scientist Award of the Physical Society of Japan

    2023.10   The Physical Society of Japan  

  3. Young Scientist Award of the Physical Society of Japan

    2023   The Physical Society of Japan   Research on unconventional proximity effects at superconductor/ferromagnet interfaces

    Sachio Komori

     More details

    Award type:Award from Japanese society, conference, symposium, etc. 

 

Papers 19

  1. Enhancement of Josephson Critical Currents in Ferromagnetic Co40Fe40B20 by Thermal Annealing Reviewed International coauthorship

    Sachio Komori, Juliet E. Thompson, Guang Yang, Graham Kimbell, Nadia Stelmashenko, Mark G. Blamire, Jason W. A. Robinson

    Physical Review Applied   Vol. 17 ( 2 ) page: L021002   2022.2

     More details

    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Physical Society (APS)  

    DOI: 10.1103/PhysRevApplied.17.L021002

    Web of Science

    Scopus

    arXiv

    Other Link: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevApplied.17.L021002/fulltext

  2. Spin-orbit coupling suppression and singlet-state blocking of spin-triplet Cooper pairs Reviewed

    Sachio Komori, James Devine-Stoneman, Kohei Ohnishi, Guang Yang, Zhanna Devizorova, Sergey Mironov, Xavier Montiel, Linde Olde Olthof, Lesley Cohen, Hidekazu Kurebayashi, Mark Blamire, Alexandre Buzdin, Jason Robinson

    Science Advances   Vol. 7 ( 3 ) page: eabe0128 - eabe0128   2021.1

     More details

    Authorship:Lead author, Corresponding author   Publishing type:Research paper (scientific journal)   Publisher:American Association for the Advancement of Science (AAAS)  

    Spin-information can be transferred between ferromagnets through a
    superconducting spacer via spin-polarized quasiparticles or triplet Cooper
    pairs. Below the critical temperature of an s-wave superconductor, an energy
    gap opens in the density of states below which the electrons pair up with
    antiparallel spins ("singlet pairs") meaning singlet supercurrents do not carry
    a net spin. However, in this state the spin-relaxation time for spin-polarized
    quasiparticle (i.e. non-superconducting carrier) currents injected from a
    ferromagnet into a superconductor at the energy gap edge, is enhanced by over 6
    orders of magnitude over the normal state. Spin can also be carried directly in
    the superconducting state through the conversion of singlet pairs into
    spin-polarized triplet pairs at magnetically inhomogeneous
    superconductor/ferromagnet interfaces. Although the decay envelope of triplet
    pairs within ferromagnetic materials is well studied, little is known about
    their decay in non-magnetic metals and superconductors, and in particular in
    presence of spin-orbit coupling (SOC). Here we report devices in which triplet
    supercurrents are created and are injected into the s-wave superconductor Nb
    with strong SOC. In the normal state of Nb, triplet pairs decay over a distance
    of 5 nm, which is an order of magnitude smaller than the decay of zero spin
    singlet pairs due to the SOC interacting with the spin associated with a
    triplet supercurrent. In the superconducting state of Nb, triplet supercurrents
    are blocked by the lack of available equilibrium states in the singlet
    superconducting gap. The results offer new insight into the dynamics between
    s-wave singlet and triplet states.

    DOI: 10.1126/sciadv.abe0128

    PubMed

    arXiv

  3. Electric field enhancement of the superconducting spin-valve effect via strain-transfer across a ferromagnetic/ferroelectric interface Invited Reviewed

    Tomohiro Kikuta, Sachio Komori, Keiichiro Imura, Tomoyasu Taniyama

    APL Materials   Vol. 12 ( 7 ) page: 071115   2024.7

     More details

    Authorship:Corresponding author   Publishing type:Research paper (scientific journal)   Publisher:AIP Publishing  

    In a ferromagnet/superconductor/ferromagnet (F/S/F) superconducting spin-valve (SSV), a change in the magnetization alignment of the two F layers modulates the critical temperature (Tc) of the S layer. The Tc-switching effect (the SSV effect) is based on the interplay between superconductivity and magnetism. The fast and large resistive switching associated with Tc-switching is suitable for nonvolatile cryogenic memory applications. However, the external magnetic field-based operation of SSVs is hindering their miniaturization, and therefore, electric field control of the SSV effect is desired. Here, we report epitaxial growth of a La0.67Ca0.33MnO3/YBa2Cu3O7/La0.67Ca0.33MnO3 SSV on a piezo-electric [Pb(Mg0.33Nb0.67)O3]0.7-[PbTiO3]0.3 (001) substrate and demonstrate electric field control of the SSV effect. Electric field-induced strain-transfer from the piezo-electric substrate increases the magnetization and Tc of the SSV and leads to an enhancement of the magnitude of Tc-switching. The results are promising for the development of magnetic-field-free superconducting spintronic devices, in which the S/F interaction is not only sensitive to the magnetization alignment but also to an applied electric field.

    DOI: 10.1063/5.0211769

    Web of Science

    Scopus

  4. Superconducting properties of bismuthate/manganite epitaxial multilayers Reviewed

    Sachio Komori, Tomoyasu Taniyama

    Superconductor Science and Technology   Vol. 37 ( 3 ) page: 035018   2024.3

     More details

    Authorship:Lead author, Corresponding author   Publishing type:Research paper (scientific journal)   Publisher:IOP Publishing  

    Abstract

    We report epitaxial growth and superconducting properties of superconductor/ferromagnet (S/F) multilayers consisting of an s-wave superconducting bismuthate BaPb<sub>0.75</sub>Bi<sub>0.25</sub>O<sub>3</sub> (BPBO) and a ferromagnetic insulating manganite La<sub>0.875</sub>Sr<sub>0.125</sub>MnO<sub>3</sub> (LSMO). We demonstrate that the superconductivity of BPBO sandwiched by LSMO is preserved down to a thickness close to the superconducting coherence length. The superconducting transition temperature of BPBO is unaffected by the magnetization alignment of the LSMO layers, which is in sharp contrast to YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7</sub> showing a clear magnetic exchange interaction. While the stable s-wave superconductivity in the S/F oxide multilayer demonstrated in this work is promising for the development of quantum spin devices with strong spin–orbit coupling, the absence of the magnetic exchange field effect highlights the importance of interface engineering for the realization of a strongly exchange-coupled s-wave S/F oxide interface.

    DOI: 10.1088/1361-6668/ad2301

    Web of Science

    Scopus

    Other Link: https://iopscience.iop.org/article/10.1088/1361-6668/ad2301/pdf

  5. Y3Fe5O12 film with multi-domain epitaxy on single-crystalline LiNbO3 substrate Reviewed

    Kazuto Yamanoi, Kenta Hase, Sachio Komori, Tomoyasu Taniyama, Yukio Nozaki

    APL Materials   Vol. 12 ( 2 ) page: 021130   2024.2

     More details

    Publishing type:Research paper (scientific journal)   Publisher:AIP Publishing  

    Y3Fe5O12 is one of the magnetic insulators that can realize high-speed and low-power-consuming spintronics devices. However, it is hard to prepare a high-quality Y3Fe5O12 film via a conventional sputtering process owing to its low crystalline texture, which leads to a crucial increase in the Gilbert damping constant. Moreover, a single crystalline Gd3Ga5O12 substrate, whose lattice constant is well matched with Y3Fe5O12, is indispensable to improve the crystallinity of the Y3Fe5O12 film. In this article, we demonstrated an epitaxial growth of multiple domains for a 30-nm-thick Y3Fe5O12 film by means of magnetron sputtering on a single crystalline 128° Y–X LiNbO3 substrate , which has been widely utilized in surface acoustic wave devices. From the pole figure of x-ray diffraction, an oblique epitaxial growth of Y3Fe5O12(400) is successfully observed on the 128° Y–X LiNbO3 substrate after a high-temperature post-annealing. The saturation magnetization is equivalent to the value of the epitaxial Y3Fe5O12 film on the Gd3Ga5O12 substrate. The relatively low effective Gilbert damping constant of 0.0039 also supports the high crystalline texture of the Y3Fe5O12 film. The developed growth technique will pave the way for the application of the Y3Fe5O12 film on magneto-acoustic devices.

    DOI: 10.1063/5.0189760

    Web of Science

    Scopus

  6. Quantized conductance in hybrid split-gate arrays of superconducting quantum point contacts with semiconducting two-dimensional electron systems Reviewed

    Kaveh Delfanazari, Jiahui Li, Yusheng Xiong, Pengcheng Ma, Reuben K. Puddy, Teng Yi, Ian Farrer, Sachio Komori, Jason W.A. Robinson, Llorenc Serra, David A. Ritchie, Michael J. Kelly, Hannah J. Joyce, Charles G. Smith

    Physical Review Applied   Vol. 21 ( 1 ) page: 014051   2024.1

     More details

    Publishing type:Research paper (scientific journal)   Publisher:American Physical Society (APS)  

    DOI: 10.1103/PhysRevApplied.21.014051

    Web of Science

    Scopus

    Other Link: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevApplied.21.014051/fulltext

  7. Large‐Scale On‐Chip Integration of Gate‐Voltage Addressable Hybrid Superconductor–Semiconductor Quantum Wells Field Effect Nano‐Switch Arrays Reviewed

    Kaveh Delfanazari, Jiahui Li, Pengchen Ma, Reuben K. Puddy, Teng Yi, Yusheng Xiong, Ian Farrer, Sachio Komori, Jason W. A. Robinson, David A. Ritchie, Michael J. Kelly, Hannah J. Joyce, Charles G. Smith

    Advanced Electronic Materials   Vol. 10 ( 2 ) page: 2300453   2023.10

     More details

    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    Abstract

    Stable, reproducible, scalable, addressable, and controllable hybrid superconductor–semiconductor (S–Sm) junctions and switches are key circuit elements and building blocks of gate‐based quantum processors. The electrostatic field effect produced by the split gate voltages facilitates the realization of nano‐switches that can control the conductance or current in the hybrid S–Sm circuits based on 2D semiconducting electron systems. Here, a novel realization of large‐scale scalable, and gate voltage controllable hybrid field effect quantum chips is experimentally demonstrated. Each chip contains arrays of split gate field effect hybrid junctions, that work as conductance switches, and are made from In<sub>0.75</sub>Ga<sub>0.25</sub>As quantum wells integrated with Nb superconducting electronic circuits. Each hybrid junction in the chip can be controlled and addressed through its corresponding source–drain and two global split gate contact pads that allow switching between their (super)conducting and insulating states. A total of 18 quantum chips are fabricated with 144 field effect hybrid Nb‐ In<sub>0.75</sub>Ga<sub>0.25</sub>As 2DEG‐Nb quantum wires and the electrical response, switching voltage (on/off) statistics, quantum yield, and reproducibility of several devices at cryogenic temperatures are investigated. The proposed integrated quantum device architecture allows control of individual junctions in a large array on a chip useful for emerging cryogenic quantum technologies.

    DOI: 10.1002/aelm.202300453

    Web of Science

    Scopus

  8. Controlling spin pumping into superconducting Nb by proximity-induced spin-triplet Cooper pairs Reviewed

    Alex Chan, Murat Cubukcu, Xavier Montiel, Sachio Komori, Alex Vanstone, Juliet Thompson, Garry Perkins, Christy Kinane, Andrew Caruana, David Boldrin, Mark Blamire, Jason Robinson, Matthias Eschrig, Hidekazu Kurebayashi, Lesley Cohen

    Communications Physics   Vol. 6 ( 1 ) page: 287   2023.10

     More details

    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    Abstract

    Proximity-induced long-range spin-triplet supercurrents, important for the field of superconducting spintronics, are generated in superconducting/ferromagnetic heterostructures when interfacial magnetic inhomogeneities responsible for spin mixing and spin flip scattering are present. The multilayer stack Nb/Cr/Fe/Cr/Nb has been shown to support such currents when fabricated into Josephson junction devices. However, creating pure spin currents controllably in superconductors outside of the Josephson junction architecture is a bottleneck to progress. Recently, ferromagnetic resonance was proposed as a possible direction, the signature of pure supercurrent creation being an enhancement of the Gilbert damping below the superconducting critical temperature, but the necessary conditions are still poorly established. Here, we demonstrate that pumping pure spin currents into a superconductor in the presence of an external magnetic field is only possible when conditions supporting proximity-induced spin-triplet effects are satisfied. Our study is an important step forward for pure spin supercurrent creation, considerably advancing the field of superconducting spintronics.

    DOI: 10.1038/s42005-023-01384-w

    Other Link: https://www.nature.com/articles/s42005-023-01384-w

  9. Antiferromagnetic ordering and signatures of enhanced spin-frustration in honeycomb-layered tellurates with Ag bilayers Reviewed

    Sachio Komori, Kohei Tada, Noboru Taguchi, Tomoyasu Taniyama, Titus Masese

    Journal of Materials Chemistry C   Vol. 11 ( 33 ) page: 11213 - 11217   2023.8

     More details

    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:Royal Society of Chemistry (RSC)  

    We report the magnetic and spin frustration properties of Ag-based honeycomb layered tellurates with magnetic honeycomb slabs separated by Ag bilayers.

    DOI: 10.1039/d3tc01915b

    Web of Science

    Scopus

  10. Controllable Perpendicular Magnetic Anisotropy in Fe/Fe100-xRhx Heterostructures Probed by Ferromagnetic Resonance Reviewed

    Hiroki Omura, Sachio Komori, Shigeo Arai, Kahoru Yoda, Keiichiro Imura, Tomoyasu Taniyama

    Physical Review Applied   Vol. 19 ( 6 ) page: 064077   2023.6

     More details

    Authorship:Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Physical Society (APS)  

    DOI: 10.1103/PhysRevApplied.19.064077

    Web of Science

    Scopus

    Other Link: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevApplied.19.064077/fulltext

  11. Interlayer coupling-dependent magnetoelastic response in synthetic antiferromagnets Reviewed

    Yuichi Hisada, Sachio Komori, Keiichiro Imura, Tomoyasu Taniyama

    Applied Physics Letters   Vol. 122 ( 22 ) page: 222402   2023.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AIP Publishing  

    In recent years, antiferromagnetic materials have been attracting increasing interest for their stability in high magnetic fields and ultrafast magnetization dynamics. Since the energy scale of an interlayer exchange coupling (IEC) in a synthetic antiferromagnet (SAF) consisting of ferromagnetic/nonmagnetic/ferromagnetic multilayers is relatively smaller than that of an exchange coupling in antiferromagnetic materials, magnetic ordering of a SAF can be potentially controlled by an electric field, which is promising for energy-saving spintronic memory devices. However, an electric field-induced magnetoelastic response of SAFs on ferroelectric materials has not been sufficiently understood due to the presence of IEC that complicates magnetization dynamics. In this study, we prepare Co/Ru/Co SAFs with various amplitude of IEC on ferroelectric Pb(Mg1/3Nb2/3)O3-PbTiO3 substrates and systematically investigate their electric field-induced magnetoelastic response. We demonstrate that the magnetoelastic response disappears at the boundary where a switching between the antiferromagnetic and ferromagnetic IEC coupling occurs. The result provides insight into the coupling of the magnetoelastic effect and IEC and is useful in designing spintronic memory devices based on SAFs.

    DOI: 10.1063/5.0151832

    Web of Science

    Scopus

  12. Enhanced magnetic modulation at a border of magnetic ordering in La1−xSrxMnO3/BaTiO3(100) heterostructure Reviewed

    Keiichiro Imura, Shota Ishikawa, Sachio Komori, Tomoyasu Taniyama

    Applied Physics Letters   Vol. 122 ( 20 ) page: 202402   2023.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AIP Publishing  

    In La1−xSrxMnO3 (LSMO)/BaTiO3 (BTO) heterostructures with a multiferroic interface, an artificial modulation of the magnetic structure is observed. The saturation magnetization of La1−xSrxMnO3 changes discontinuously due to in-plane distortions caused by a structural phase transition of a BaTiO3 substrate. Polarity reversal of the external electric field also causes a reversible switching in the magnetization. The magnitude of both magnetic modulations, due to the magnetoelastic and electric field effects, is concomitantly enhanced at a critical composition xc∼0.55, locating at a border of the magnetic phase transition. The polarity-dependent change in magnetization is possibly attributed to a change in the concentration of oxygen ions at the LSMO/BTO interface, indicating that the exchange interaction is reciprocally driven from being ferromagnetic to antiferromagnetic by the electric field polarity.

    DOI: 10.1063/5.0150917

    Web of Science

    Scopus

  13. Electric field modulation of spin-flop behaviors in Co/Ru/Co/PMN-PT(011) artificial multiferroic heterostructures

    Yuichi Hisada, Sachio Komori, Keiichiro Imura, Tomoyasu Taniyama

    2023 IEEE International Magnetic Conference - Short Papers (INTERMAG Short Papers)     2023.5

     More details

    Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    DOI: 10.1109/intermagshortpapers58606.2023.10228509

    Scopus

  14. Epitaxial Co<inf>2</inf>FeSi/LiNbO<inf>3</inf> multiferroic heterostructures with a low damping constant

    Yamada S., Usami T., Komori S., Nagata S., Nozaki Y., Taniyama T., Hamaya K.

    2023 IEEE International Magnetic Conference - Short Papers, INTERMAG Short Papers 2023 - Proceedings     2023

     More details

    Publisher:2023 IEEE International Magnetic Conference - Short Papers, INTERMAG Short Papers 2023 - Proceedings  

    Piezoelectric LiNbO3 has been widely utilized to generate and detect spin waves in surface acoustic wave devices. Here we demonstrate an epitaxial Co-based Heusler alloy on a LiNbO3 128° Y-cut (LN-128Y) substrate by molecular beam epitaxy. Although there is no matching between the lattice length and symmetry, the insertion of a bcc metal buffer layer enables to grow L21 - ordered epitaxial Co2FeSi films on the LN-128Y substrate. The epitaxial Co2FeSi/LN- 128Y multiferroic heterostructures show a high saturation magnetization of ~1235 eμcc and a low damping constant of ~6 × 10-3. This study will open a way for an efficient electric-field control of the spin waves in surface acoustic wave devices.

    DOI: 10.1109/INTERMAGShortPapers58606.2023.10228793

    Scopus

  15. Emergence of Quasi Two-Dimensional Electronic States at the Interface of LSMO/STO via Lattice Mismatch-Induced Strains Reviewed

    Satya Prakash Pati, Takamasa Usami, Sachio Komori, Tomoyasu Taniyama

    ACS Applied Electronic Materials   Vol. 4 ( 9 ) page: 4748 - 4754   2022.9

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Chemical Society (ACS)  

    DOI: 10.1021/acsaelm.2c00967

    Web of Science

    Scopus

  16. Unveiling unconventional magnetism at the surface of Sr2RuO4 Reviewed International coauthorship

    R. Fittipaldi, R. Hartmann, M. T. Mercaldo, S. Komori, A. Bjørlig, W. Kyung, Y. Yasui, T. Miyoshi, L. A. B. Olde Olthof, C. M. Palomares Garcia, V. Granata, I. Keren, W. Higemoto, A. Suter, T. Prokscha, A. Romano, C. Noce, C. Kim, Y. Maeno, E. Scheer, B. Kalisky, J. W. A. Robinson, M. Cuoco, Z. Salman, A. Vecchione, A. Di Bernardo

    Nature Communications   Vol. 12 ( 1 ) page: 5792   2021.10

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    <title>Abstract</title>Materials with strongly correlated electrons often exhibit interesting physical properties. An example of these materials is the layered oxide perovskite Sr<sub>2</sub>RuO<sub>4</sub>, which has been intensively investigated due to its unusual properties. Whilst the debate on the symmetry of the superconducting state in Sr<sub>2</sub>RuO<sub>4</sub> is still ongoing, a deeper understanding of the Sr<sub>2</sub>RuO<sub>4</sub> normal state appears crucial as this is the background in which electron pairing occurs. Here, by using low-energy muon spin spectroscopy we discover the existence of surface magnetism in Sr<sub>2</sub>RuO<sub>4</sub> in its normal state. We detect static weak dipolar fields yet manifesting at an onset temperature higher than 50 K. We ascribe this unconventional magnetism to orbital loop currents forming at the reconstructed Sr<sub>2</sub>RuO<sub>4</sub> surface. Our observations set a reference for the discovery of the same magnetic phase in other materials and unveil an electronic ordering mechanism that can influence electron pairing with broken time reversal symmetry.

    DOI: 10.1038/s41467-021-26020-5

    Web of Science

    Scopus

    PubMed

    Other Link: https://www.nature.com/articles/s41467-021-26020-5

  17. Pure Spin Currents Driven by Colossal Spin–Orbit Coupling on Two-Dimensional Surface Conducting SrTiO3 Reviewed

    Mi-Jin Jin, Doo-Seung Um, Kohei Ohnishi, Sachio Komori, Nadia Stelmashenko, Daeseong Choe, Jung-Woo Yoo, Jason W. A. Robinson

    Nano Letters   Vol. 21 ( 15 ) page: 6511 - 6517   2021.8

     More details

    Publishing type:Research paper (scientific journal)   Publisher:American Chemical Society (ACS)  

    DOI: 10.1021/acs.nanolett.1c01607

  18. Interlayer Transport and Josephson Coupling in a 1212-type Cuprate Superconductor with a (Pb,Cu)–O Barrier Layer Reviewed

    Sachio Komori, Itsuhiro Kakeya

    Journal of the Physical Society of Japan   Vol. 90 ( 2 ) page: 024702 - 024702   2021.2

     More details

    Authorship:Lead author, Corresponding author   Publishing type:Research paper (scientific journal)   Publisher:Physical Society of Japan  

    DOI: 10.7566/jpsj.90.024702

  19. Growth, strain, and spin-orbit torques in epitaxial Ni-Mn-Sb films sputtered on GaAs Reviewed

    Na Zhao, Aakanksha Sud, Hiroaki Sukegawa, Sachio Komori, Konstantinos Rogdakis, Kazuto Yamanoi, James Patchett, Jason Robinson, Chiara Ciccarelli, Hidekazu Kurebayashi

    Physical Review Materials   Vol. 5 ( 1 )   2021.1

     More details

    Publishing type:Research paper (scientific journal)   Publisher:American Physical Society (APS)  

    DOI: 10.1103/physrevmaterials.5.014413

    Other Link: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevMaterials.5.014413/fulltext

▼display all

Presentations 13

  1. Triplet proximity effects and superconducting exchange coupling at a superconductor/ferromagnet interface Invited

    Sachio Komori

    The 84th JSAP Autumn Meeting 2023  2023.9.22 

     More details

    Event date: 2023.9

  2. Long-range magnetic exchange coupling mediated by anisotropic superconductivity Invited

    Sachio Komori, Sogo Suzuki, Angelo Di Bernardo, Jason Robinson, Tomoyasu Taniyama

    28th Vortex Physics Workshop Japan  2022.12.16 

     More details

    Event date: 2022.12

  3. Triplet supercurrents in ferromagnets and singlet superconductors Invited

    Sachio Komori

    Materials Research Meeting 2021  2021.12.15 

     More details

    Event date: 2021.12

  4. Unconventional proximity effects at superconductor/ferromagnet interfaces Invited

    Sachio Komori

    Physical Society of Japan Spring Meeting 2024  2024.2.19 

     More details

    Event date: 2024.3

  5. Superconducting exchange coupling and spin-transport at oxide superconductor/ferromagnet interfaces Invited

    Sachio Komori

    13th International Conference on the Intrinsic Josephson Effect and High-Temperature Superconductivity  2023.9.1 

     More details

    Event date: 2023.8 - 2023.9

  6. FIB fabrication of singlet and triplet Josephson devices Invited

    Sachio Komori

    International workshop on nanostructured novel superconductors  2023.3.18 

     More details

    Event date: 2023.3

  7. Creation and control of spin-triplet supercurrents

    Sachio Komori

    The 70th JSAP Spring Meeting 2023  2023.3.15 

     More details

    Event date: 2023.3

  8. Oxide superconducting spintronics Invited

    Sachio Komori

    Electron & Spin on Quantum Materials  2023.2.2 

     More details

    Event date: 2023.2

  9. Magnetic exchange through oxide superconductors Invited

    Sachio Komori

    Unconventional transport in superconducting & magnetic systems with spin-orbit coupling  2022.11.15 

     More details

    Event date: 2022.11

    Presentation type:Oral presentation (invited, special)  

  10. Oxide superconducting spin-valves and exchange coupling Invited

    Sachio Komori

    International workshop on superconducting spintronics (Superconducting spintronics 2022)  2022.11.2 

     More details

    Event date: 2022.11

    Presentation type:Oral presentation (invited, special)  

  11. Superconducting filtering of triplet supercurrents Invited

    Sachio Komori, Jason Robinson

    Low dimensional superconducting hybrids for novel quantum functionalities  2021.10.14 

     More details

    Event date: 2021.10

  12. Giant enhancement of Josephson critical currents in CoFeB through thermal annealing

    Sachio Komori, Juliet Thompson, Jason Robinson

    The 82nd JSAP Autumn Meeting 2021  2021.9.12 

     More details

    Event date: 2021.9

  13. Combining a high temperature superconductor with ferromagnetic and ferroelectric materials for energy-efficient electronics Invited

    Sachio Komori

    Seminar Talk in the Center for Advanced Studies in Electronics Sciences & Technology, School of Physics, University of Hyderabad  2024.3.11 

▼display all

Research Project for Joint Research, Competitive Funding, etc. 1

  1. 超伝導マルチフェロイクスによる超省電力メモリの創製

    2022.4 - 2029.3

    創発的研究支援事業 

    小森 祥央

KAKENHI (Grants-in-Aid for Scientific Research) 2

  1. 革新的スピン波材料のデザイン手法の開拓

    Grant number:23KK0086  2023.9 - 2026.3

    日本学術振興会  科学研究費助成事業  国際共同研究加速基金(海外連携研究)

    谷山 智康, 小森 祥央, 井村 敬一郎, 小森 祥央, 井村 敬一郎

      More details

    Authorship:Coinvestigator(s) 

    磁気モーメントの歳差運動が空間を伝播する一形態としてスピン波が広く知られている。スピン波コンピューティングデバイスなどにおいてスピン波を情報伝送媒体として利用するためには、スピン波を長距離に渡り伝播させることが可能な強磁性材料の開発が必須となる。本研究では、スピン波の長距離伝播を実現する強磁性材料をデザインするための包括的な指針を構築し、その設計指針に基づいて強磁性スピン波材料を創出することで、スピン波の長距離伝播の実証までを目的とする。より具体的には、状態密度と磁気異方性を変調した磁性酸化物薄膜のスピン波伝播長の精密計測を通して、スピン波減衰の物理機構を解明し、上記の目的を達成を目指す。

  2. 高温超伝導スピントロニクスの開拓 International coauthorship

    Grant number:20K23374  2021.3 - 2024.3

    日本学術振興会  科学研究費助成事業  国際共同研究加速基金(帰国発展研究)

    小森 祥央

      More details

    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\53560000 ( Direct Cost: \41200000 、 Indirect Cost:\12360000 )

    高温超伝導体を用いて磁気情報を輸送するための学理の構築を行う。ナノスケールの強磁性体と高温超伝導体の界面において、強磁性体から高温超伝導体への交換磁場の印加および純スピン流の注入を行う。高温超伝導体の状態密度および超伝導キャリアのスピンの対称性を分析することで、高温超伝導体が交換磁場および純スピン流を長距離で輸送するために重要なパラメータを抽出し、高温超伝導スピントロニクスデバイス実現の可能性を探求する。
    2022年度は、高温超伝導体中のスピン輸送を調べることを目的とした酸化物の超伝導体/強磁性体のナノ構造の作製と低温(1.5K)かつ高周波(40GHz以上)で強磁性共鳴の研究を行うためのシステムの構築を行った。d波の超伝導ギャップの対称性を有する高温超伝導体のみならず、s波の対称性を有する酸化物超伝導体を用いて、強磁性体から超伝導体中に侵入する磁気秩序(交換磁場)の測定を行ったところ、超伝導ギャップが異方的になる(d波に近づく)につれて、超伝導体中に磁気秩序が長距離で侵入することが見出された。これは超伝導ギャップの大きさが実効的に小さくなるd波のノード部分に由来するものであると考えられ、d波対称性を有する高温超伝導体が磁気秩序の長距離伝搬に適していることを実証する結果となった。超伝導体中において磁気秩序をコヒーレンス長を上回るスケールで伝送可能であることを示す本研究成果は、高温超伝導体を用いたスピントロニクスデバイスに特有の機能として期待される。国際共同研究に関しては、英国ケンブリッジ大学のJason Robinson教授やイタリア・サレルノ大学のMario Cuoco教授とオンラインのみならず海外で直接議論を進める機会を設け上記の研究成果の理論をはじめとしたディスカッションを行った。また低温高周波測定に関しては、韓国UNISTのDr. Mi-Jin Jinの研究室に短期訪問し、ノウハウを得ることによってセットアップを行った。また、集束イオンビームを用いた微細構造超伝導体研究の最先端の研究者であるUniversity of California, RiversideのShane Cybart先生に来日していただく機会を設け、トンネル接合を用いた高温超伝導体/強磁性体界面での状態密度分析に関する共同研究を開始した。
    s波およびd波対称性を有する酸化物超伝導体と強磁性体のナノ界面の物性評価のための高品質な試料の作製が可能になり、界面での超伝導と磁性の相互作用が超伝導の対称性によって異なることが示唆される重要な知見を得ることができたためである。また、低温測定および高周波測定のセットアップが完了し、DCの電気・磁気測定のみならずGHz帯の測定によって高温超伝導体に強磁性体からスピンを注入する研究を行うことが可能になり、これらによって酸化物超伝導体中の交換磁場の長距離伝搬に関する研究成果も得られており、国際共同研究への展開も進んでいるためである。
    次年度は、今年度構築した高周波測定系において高温超伝導体のスピン輸送特性を系統的に評価する。これによって高温超伝導体中における磁気秩序がスピン輸送にもたらす影響、さらにはスピン三重項高温超伝導状態の生成による長距離スピン輸送が可能かといった超伝導デジタルコンピューティングにも応用可能な知見を得るための研究を行う。
    またShane Cybart教授との共同研究による集束イオンビーム加工によるナノデバイスの作製によって、高温超伝導体/強磁性体界面における状態密度の評価、また高温超伝導/強磁性体構造からなるジョセフソントンネル接合の研究も行い、こちらもナノエレクトロニクスへの応用可能性を検証する。