Yuki K. Wakabayashi

NTT Basic Research Laboratories　Low-Dimensional Nanomaterials Research Group

HOME

PUBLICATION

RESEARCH

METHOD

ACCESS

日本語

Publication (*: Corresponding author)

1. SrRuO3 under tensile strain: Thickness-dependent electronic and magnetic properties
   Y. K. Wakabayashi*, M. Kobayashi, Y. Seki, K. Yamagami, T. Takeda, T. Ohkochi, Y. Taniyasu, Y. Krockenberger, and H. Yamamoto
   arXiv:2404.05438 (2024).
2. Magnetic anisotropy driven by ligand in 4d transition-metal oxide SrRuO3
   Y. K. Wakabayashi*, M. Kobayashi, Y. Seki, Y. Kotani, T. Ohkochi, K. Yamagami, M. Kitamura, Y. Taniyasu, Y. Krockenberger, and H. Yamamoto
   APL Materials 12, 041119 (2024).
3. Scattering-dependent transport of SrRuO3 films: From Weyl fermion transport to hump-like Hall effect anomaly
   S. Kaneta-Takada, Y. K. Wakabayashi* (co-first), Y. Krockenberger, H. Irie, S. Ohya, M. Tanaka, Y. Taniyasu, and H. Yamamoto
   Physical Review Materials 7, 054406 (2023).
4. Origin of magnetically dead layers in spinel ferrites MFe2O4 grown on Al2O3: Effects of post-deposition annealing studied by XMCD
   Y. Nonaka*, Y. K. Wakabayashi, G. Shibata, S. Sakamoto, K. Ikeda, Z. Chi, Y. Wan, M. Suzuki, A. Tanaka, M. Tanaka, and A. Fujimori
   Physical Review Materials 7, 044413 (2023).
5. Stoichiometric growth of SrTiO3 films via Bayesian optimization with adaptive prior mean
   Y. K. Wakabayashi*, T. Otsuka* (co-first), Y. Krockenberger, H. Sawada, Y. Taniyasu, and H. Yamamoto
   APL Machine Learning 1, 026104 (2023).
   Selected as a Featured Article.
   Selected as a Special Collections.
6. Isotropic orbital magnetic moments in magnetically anisotropic SrRuO3 films
   Y. K. Wakabayashi*, M. Kobayashi, Y. Takeda, M. Kitamura, T. Takeda, R. Okano, Y. Krockenberger, Y. Taniyasu, and H. Yamamoto
   Physical Review Materials 6, 094402 (2022).
7. High-mobility two-dimensional carriers from surface Fermi arcs in magnetic Weyl semimetal films
   S. Kaneta-Takada, Y. K. Wakabayashi* (co-first), Y. Krockenberger, T. Nomura, Y. Kohama, H. Irie, K. Takiguchi, S. Ohya, M. Tanaka, Y. Taniyasu, and H. Yamamoto
   npj Quantum Materials 7, 102 (2022).
8. Bayesian optimization with experimental failure for high-throughput materials growth
   Y. K. Wakabayashi*, T. Otsuka* (co-first), Y. Krockenberger, H. Sawada, Y. Taniyasu, and H. Yamamoto
   npj Computational Materials 8, 180 (2022).
9. Electron-Beam-Evaporation-Based Multi-Source Oxide MBE as a Synthesis Method for High-Quality and Novel Magnetic Materials—Beyond 3d Transition Metal Compounds
   H. Yamamoto*, Y Krockenberger, Y. Taniyasu, and Y. K. Wakabayashi*
   Journal of Crystal Growth 593, 126778 (2022).
10. Intrinsic physics in magnetic Weyl semimetal SrRuO3 films addressed by machine-learning-assisted molecular beam epitaxy (Review paper)
    Y. K. Wakabayashi*, Y. Krockenberger, T. Otsuka, H. Sawada, Y. Taniyasu, and H. Yamamoto
    Japanese Journal of Applied Physics 62, SA0801 (2022).
11. Single-domain perpendicular magnetization induced by the coherent O 2p-Ru 4d hybridized state in an ultra-high-quality SrRuO3 film
    Y. K. Wakabayashi*, M. Kobayashi* (co-first), Y. Takeda, K. Takiguchi, H. Irie, S.-i. Fujimori, T. Takeda, R. Okano, Y. Krockenberger, Y. Taniyasu, and H. Yamamoto
    Physical Review Materials 5, 124403 (2021).
12. Reduced magnetocrystalline anisotropy of CoFe2O4 thin films studied by angle-dependent x-ray magnetic circular dichroism
    Y. Nonaka*, Y. K. Wakabayashi, G. Shibata, S. Sakamoto, K. Ikeda, Z. Chi, Y. Wan, M. Suzuki, T. Koide, M. Tanaka, R. Nakane, and A. Fujimori
    AIP advances 11, 085317 (2021).
13. Wide-range epitaxial strain control of electrical and magnetic properties in high-quality SrRuO3 films
    Y. K. Wakabayashi*, S. Kaneta-Takada, Y. Krockenberger, Y. Taniyasu, and H. Yamamoto
    ACS Applied Electronic Materials 3, 2712 (2021).
14. Structural and transport properties of highly Ru-deficient SrRu0.7O3 thin films prepared by molecular beam epitaxy: comparison with stoichiometric SrRuO3
    Y. K. Wakabayashi*, S. Kaneta-Takada (co-first), Y. Krockenberger, K. Takiguchi, S. Ohya, M. Tanaka, Y. Taniyasu, and H. Yamamoto
    AIP Advances 11, 035226 (2021).
15. Thickness-dependent quantum transport of Weyl fermions in ultra-high-quality SrRuO3 films
    S. Kaneta-Takada, Y. K. Wakabayashi* (co-first), Y. Krockenberger, S. Ohya, M. Tanaka, Y. Taniyasu, and H. Yamamoto
    Applied Physics Letters 118, 092408 (2021).
16. Quantum transport evidence of Weyl fermions in an epitaxial ferromagnetic oxide
    K. Takiguchi, Y. K. Wakabayashi* (co-first), H. Irie, Y. Krockenberger, T. Otsuka, H. Sawada, S. A. Nikolaev, H. Das, M. Tanaka, Y. Taniyasu, and H. Yamamoto
    Nature Communications 11, 4969 (2020).
    (NTT News Release)
17. Characterization of in-gap states in epitaxial CoFe2O4(111) layers grown on Al2O3(111)/Si(111) by resonant inelastic x-ray scattering
    Y. K. Wakabayashi*, T. Tokushima, K. Kuga, H. Yomosa, M. Oura, H. Fujiwara, T. Ishikawa, M. Tanaka, T. Kiss*, and R. Nakane*
    arXiv:1910.05734
18. Magnetization process of the insulating ferromagnetic semiconductor (Al,Fe)Sb
    S. Sakamoto, L. D. Anh, P. N. Hai, Y. Takeda, M. Kobayashi, Y. K. Wakabayashi, Y. Nonaka, K. Ikeda, Z. Chi, Y. Wan, M. Suzuki, Y. Saitoh, H. Yamagami, M. Tanaka, and A. Fujimori
    Physical Review B 101, 075204 (2020).
19. Machine-learning-assisted thin-film growth: Bayesian optimization in molecular beam epitaxy of SrRuO3 thin films
    Y. K. Wakabayashi*, T. Otsuka, Y. Krockenberger, H. Sawada, Y. Taniyasu, and H. Yamamoto
    APL Materials 7, 101114 (2019).
20. Electronic structure of the high-TC ferromagnetic semiconductor (Ga,Fe)Sb: X-ray magnetic circular dichroism and resonance photoemission spectroscopy studies
    S. Sakamoto, N. T. Tu, Y. Takeda, S.-i. Fujimori, P. N. Hai, L. D. Anh, Y. K. Wakabayashi, G. Shibata, M. Horio, K. Ikeda, Y. Saitoh, H. Yamagami, M. Tanaka, and A. Fujimori
    Physical Review B 100, 035204 (2019).
21. Ferromagnetism above 1000 K in a highly cation-ordered double-perovskite insulator Sr3OsO6
    Y. K. Wakabayashi*, Y. Krockenberger, N. Tsujimoto, T. Boykin, S. Tsuneyuki, Y. Taniyasu, and H. Yamamoto
    Nature communications 10, 535 (2019).
    Selected as Editor's Highlights.
    (NTT News Release)
22. Cation distribution and magnetic properties in ultrathin (Ni1-xCox)Fe2O4 (x = 0 - 1) layers on Si(111) studied by soft x-ray magnetic circular dichroism
    Y. K. Wakabayashi*, Y. Nonaka, Y. Takeda, S. Sakamoto, K. Ikeda, Z. Chi, G. Shibat, A. Tanaka, Y. Saitoh, H. Yamagami, M. Tanaka, A. Fujimori, and R. Nakane*
    Physical Review Materials 2, 104416 (2018).
23. Improved adaptive sampling method utilizing Gaussian process regression for prediction of spectral peak structures
    Y. K. Wakabayashi*, T. Otsuka*, Y. Taniyasu, H. Yamamoto, and H. Sawada*
    Applied Physics Express 11, 112401 (2018).
24. Impurity band conduction in group-IV ferromagnetic semiconductor Ge1-xFex with nanoscale fluctuations in Fe concentration
    Y. Ban, Y. K. Wakabayashi, R. Nakane, and M. Tanaka
    Journal of Applied Physics 124, 113902 (2018).
25. Magnetic states of the weakly ferromagnetic iron-based superconductor Sr2VFeAsO{3-Δ} studied by x-ray magnetic circular dichroism
    M. Horio, Y. Takeda, H. Namiki, T. Katagiri, Y. K. Wakabayashi, S. Sakamoto, Y. Nonaka, G. Shibata, K. Ikeda, Y. Saitoh, H. Yamagami, T. Sasagawa, and A. Fujimori
    Journal of the Physical Society of Japan 87, 105001 (2018).
26. Quantum size effect in a Fe quantum well detected by resonant tunneling carriers injected from a p-type Ge semiconductor electrode
    R. Suzuki*, Y. K. Wakabayashi, K. Okamoto, M. Tanaka*, and S. Ohya*
    Applied Physics Letters 112, 152402 (2018).
27. Effects of annealing gas and drain doping concentration on electrical properties of Ge-source/Si-channel heterojunction tunneling FETs
    T.-E. Bae*, Y. Wakabayashi, R. Nakane, M. takenaka, and S. Takagi*
    Japanese Journal of Applied Physics 57, 04FD11 (2018).
28. Fe concentration dependence of tunneling magnetoresistance in magnetic tunnel junctions using group-IV ferromagnetic semiconductor GeFe
    K. Takiguchi*, Y. K. Wakabayashi, K. Okamoto, M. Tanaka*, and S. Ohya*
    AIP advances 7, 105202 (2017).
29. Observation of the inverse spin Hall effect in the topological crystalline insulator SnTe using spin pumping
    S. Ohya*, A. Yamamoto, T. Yamaguchi, R. Ishikawa, R. Akiyama, L. D. Anh, S. Goel, Y. K. Wakabayashi, S. Kuroda*, and M. Tanaka*
    Physical Review B 96, 094424 (2017).
30. Electronic structure and magnetic properties of magnetically dead layers in epitaxial CoFe2O4/Al2O3/Si(111) films studied by X-ray magnetic circular dichroism
    Y. K. Wakabayashi*, Y. Nonaka, Y. Takeda, S. Sakamoto, K. Ikeda, Z. Chi, G. Shibata, A. Tanaka, Y. Saitoh, H. Yamagami, M. Tanaka, A. Fujimori, and R. Nakane*
    Physical Review B 96, 104410 (2017).
31. Origin of robust nanoscale ferromagnetism in Fe-doped Ge revealed by angle-resolved photoemission spectroscopy and first-principles calculation
    S. Sakamoto, Y. K. Wakabayashi, Y. Takeda, S.-i Fujimori, H. Suzuki, Y. Ban, H. Yamagami, M. Tanaka, S. Ohya, and A. Fujimori
    Physical Review B 95, 075203 (2017).
32. Origin of the large positive magnetoresistance in Ge1-xMnx granular thin films
    Y. K. Wakabayashi*, R. Akiyama, Y. Takeda, M. Horio, G. Shibata, S. Sakamoto, Y. Ban, Y. Saitoh, H. Yamagami, A. Fujimori, M. Tanaka, and S. Ohya*
    Physical Review B 95, 014417 (2017).
33. Tunneling magnetoresistance in trilayer structures composed of group-IV ferromagnetic semiconductor Ge1-xFex, MgO, and Fe
    Y. K. Wakabayashi*, K. Okamoto,  Y. Ban, S. Sato, M. Tanaka*, and S. Ohya*
    Applied Physics Express 9, 123001 (2016).
    Selected as Highlights of 2016.
34. Room-temperature local ferromagnetism and its nanoscale expansion in the ferromagnetic semiconductor Ge1–xFex
    Y. K. Wakabayashi*, S. Sakamoto, Y. Takeda, K. Ishigami, Y. Takahashi, Y. Saitoh, H. Yamagami, A. Fujimori, M. Tanaka*, and S. Ohya*
    Scientific Reports 6, 23295 (2016).
35. Soft X-ray angle-resolved photoemission with micro-positioning techniques for metallic V2O3
    H. Fujiwara*, T. Kiss, Y. K. Wakabayashi, Y. Nishitani, T. Mori, Y. Nakata, S. Kitayama, K. Fukushima, S. Ikeda, H. Fushimoto, Y. Minowa, S. -K. Mo, J. Denlinger, J. W. Allen, P. Metcalf, M. Imai, K. Yoshimura, S. Suga, T. Muro, and A. Sekiyama
    Journal of Synchrotron Radiation 22 (2015).
36. Ge/Si Hetero-Junction Tunnel Field-Effect Transistors and Their Post Metallization Annealing Effect
    M. Kim, Y. K. Wakabayashi, M. Yokoyama, R. Nakane, M. Takenaka, and S. Takagi
    IEEE Transactions on Electron Devices 62, 9 (2015).
37. High Ion/Ioff Ge-source ultrathin body strained-SOI Tunnel FETs
    M. Kim, Y. Wakabayashi, R. Nakane, M. Yokoyama, M. Takenaka, and S. Takagi
    IEEE International Electron Devices Meeting (IEDM) (2014) pp. 331-334.
38. Annealing-induced enhancement of ferromagnetism and nano-particle formation in the ferromagnetic semiconductor GeFe
    Y. K. Wakabayashi, Y. Ban, S. Ohya, and M. Tanaka
    Physical Review B 90, 205209 (2014).
39. Important role of the non-uniform Fe distribution for the ferromagnetism in group-IV-based ferromagnetic semiconductor GeFe
    Y. K. Wakabayashi, S. Ohya, Y. Ban, and M. Tanaka
    Journal of Applied Physics 116, 173906 (2014).
40. Carrier transport properties of the Group-IV ferromagnetic semiconductor Ge1-xFex with and without boron doping
    Y. Ban*, Y. Wakabayashi, R. Akiyama, R. Nakane, and M. Tanaka*
    AIP advances 4, 097108 (2014).

Review and proceeding

1. [Review (in Japanese)] Si(111)基板上に作製したCoFe2O4/Al2O3の界面付近の磁性と電子状態の研究
   野中洋亮，若林勇希，芝田悟朗，酒巻真粧子，雨宮健太，田中雅明，中根了昌，藤森淳
   PF News 36, No. 2, 32 (2018).
2. [proceeding] Performance Improvement of Ge-source/Si-channel Hetero-Junction Tunneling FETs: Effects of Annealing Gas and Drain Doping Concentration
   T. -E. Bae, Y. Wakabayashi, R. Nakane, M. Yokoyama, M. Takenaka and S. Takagi
   Extended Abstracts of the 2013 International Conference on Solid State Devices and Materials, E-3-03 (2017).
3. [Review (in Japanese)] IV族強磁性半導体GeFeの物性解明と磁気トンネル接合
   Y. K. Wakabayashi
   応用電子物性分科会会誌 22巻4号, 143 (2016).
4. [Review (in Japanese)] 軟X線角度分解光電子分光による強磁性半導体Ge1-xFexの電子構造の解明
   坂本祥哉，若林勇希，竹田幸治，藤森伸一，鈴木博人，伴芳祐，山上浩志，田中雅明，大矢忍，藤森淳
   放射光　29, No. 2, 104 (2016).
5. [proceeding (in Japanese)] ゲルマニウムソース薄膜ひずみSOIトンネルFETの実現とその電気特性に与えるひずみ、MOS界面 、バックバイアスの効果
   金 閔洙、若林勇希、中根了昌、横山正史、竹中充、高木信一
   電子情報通信学会技術研究報告. 114, 9-12 (2015).
6. [proceeding] Electrical Characteristics of Ge/Si Hetero-Junction Tunnel Field-Effect Transistors and their Post Annealing Effects
   M. Kim, Y. Wakabayashi, R. Nakane, M. Yokoyama, M. Takenaka and S. Takagi
   Extended Abstracts of the 2013 International Conference on Solid State Devices and Materials, p624-625 (2013).

Invited talk

1. IV族強磁性半導体Ge1-xFexの物性解明と磁気トンネル接合
   Yuki K. Wakabayashi
   応用物理学会応用電子物性分科会・スピントロニクス研究会共催「スピントロニクス材料の新展開」 2016年11月21日
2. Search for oxide thin films by utilizing statistical machine learning
   Yuki K. Wakabayashi
   The 66th JSAP Spring Meeting Symposium "Present and future on informatics technologies" March 10, 2019
3. Jeff= 3/2 ferromagnetic insulating state above 1000 K in a double perovskite osmate Sr3OsO6
   Yuki K. Wakabayashi
   The 80th JSAP Autumn Meeting "Young Scientist Presentation Award Speech" September 18, 2019
4. Molecular beam epitaxy and utilization of machine learning for 4d and 5d ferromagnetic oxides
   Yuki K. Wakabayashi
   The 80th JSAP Autumn Meeting Symposium "New spintronic materials and their physical properties" September 19, 2019
5. Molecular beam epitaxy and utilization of machine learning for 4d and 5d ferromagnetic perovskites
   Yuki K. Wakabayashi
   CSRN-Tokyo Workshop 2019「スピントロニクス新機能物質と巨大物性応答」 November 23, 2019
6. Molecular beam epitaxy and utilization of machine learning for development of novel and high-quality 4d and 5d magnetic oxides
   Yuki K. Wakabayashi
   The 29th Annual Meeting of MRS-J "Unconventional physical properties generated from spin textures and its applications" November 28, 2019
7. Molecular beam epitaxy and utilization of machine learning for development of novel and high-quality 4d and 5d magnetic oxides
   Yuki K. Wakabayashi
   122nd Tokyo Institute of Technology MSL Lecture, February 28, 2020
8. Molecular beam epitaxy and utilization of machine learning for development of novel and high-quality 4d and 5d magnetic oxides
   Yuki K. Wakabayashi
   日本磁気学会 第76回スピントロニクス専門研究会 2020年9月25日
9. Machine-learning-assisted molecular beam epitaxy for growth of high-quality magnetic oxides
   Yuki K. Wakabayashi
   応用物理学会薄膜表面表面物理分科会「情報データ科学に基づく結晶材料・界面・プロセス工学の新展開」 2020年11月13日
10. Machine-learning-assisted molecular beam epitaxy for growth of high-quality magnetic oxides
    Yuki K. Wakabayashi
    日本学術振興会プラズマ材料科学第153委員会「機械学習を利用したプラズマ材料プロセッシング」 2020年12月18日
11. Exploration of physical properties of Weyl fermions in magnetic oxides grown by machine-learning-assisted molecular beam epitaxy
    Yuki K. Wakabayashi
    強的秩序とその操作に関わる第12回 講演会 2021年1月4日
12. Magnetic oxides grown by machine-learning-assisted molecular beam epitaxy
    Yuki K. Wakabayashi
    日本学術振興会 先進薄膜界面機能創成委員会「マテリアルインフォマティクスを活用したモノ作り最前線」 2021年6月30日
13. Exploration of physical properties of Weyl fermions in magnetic oxides grown by machine-learning-assisted molecular beam epitaxy
    Yuki K. Wakabayashi
    第11回 酸化物研究の新機軸に向けた学際討論会 2021年8月6日
14. Magnetic oxides grown by machine-learning-assisted molecular beam epitaxy
    Yuki K. Wakabayashi
    第50回結晶成長国内会議（JCCG-50) 2021年10月27日
15. Exploration of physical properties of Weyl fermions in magnetic oxides grown by machine-learning-assisted molecular beam epitaxy
    Yuki K. Wakabayashi
    日本磁気学会、応用物理学会共催「AI、インフォマティクスを活用したスピントロニクス研究の最前線」 2021年11月19日
16. Machine-Learning-Assisted Molecular Beam Epitaxy for Growth of High-Quality Magnetic Oxides
    Yuki K. Wakabayashi
    14th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials / 15th International Conference on Plasma Nano Technology & Science (ISPlasma 2022 / IC PLANTS 2022), March 10, 2022
17. Machine-learning-assisted molecular beam epitaxy of magnetic Weyl oxide SrRuO3 and its observations by quantum transport, XMCD, and soft X-ray photoemission experiments
    Yuki K. Wakabayashi
    QST未来ラボ次世代放射光利用研究グループ 2021年度公開ワークショップ「光電子分光と軟X線磁気分光の融合利用による量子マテリアルの研究」 2022年3月28日
18. Exploration of physical properties of magnetic Weyl oxide SrRuO3 grown by machine-learning-assisted molecular beam epitaxy (ML-MBE)
    Yuki K. Wakabayashi
    日本磁気学会　第238回研究会「マテリアルズインフォマティクスの進展と磁性材料への応用」 2022年10月25日
19. Machine-learning-assisted growth of quantum materials
    Yuki K. Wakabayashi
    パターン認識・メディア理解研究会（PRMU） 2023年3月3日
20. Accelerating materials and device research by developing Bayesian optimization for materials synthesis
    Yuki K. Wakabayashi
    日本表面真空学会　表面科学セミナー2024 2024年3月14日