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Kei Hayashi

Section

Graduate School of Engineering

Job title

Associate Professor

Degree

博士（理学）（東京大学）

researchmap

https://researchmap.jp/read0209405

J-GLOBAL ID

200901062808610497

ORCID

https://orcid.org/0000-0002-7948-6781

Researcher ID

O-7650-2017

Research History 4

2014/04 - Present

Graduate School of Engineering, Tohoku University　Department of Applied Physics,　Associate Professor
2007/04 - 2014/03

Graduate School of Engineering, Tohoku University　Department of Appplied Physics　Assistant Professor
2006/01 - 2007/03

Graduate School of Engineering, Tohoku University　Department of Applied Physics　Research Associate
2002/04 - 2005/12

Photodynamics Research Center, Riken　Researcher

Education 3

The University of Tokyo　Graduate School of Science　Department of Physics

- 2002/03
The University of Tokyo　Graduate School of Science　Department of Physics

- 1999/03
The University of Tokyo　Faculty of Science　Department of Physics

- 1997/03

Committee Memberships 26

日本熱電学会　研究会委員会委員

2022/09 - Present
APEX/JJAP Editor

2022/04 - Present
Elsevier　Early Career Advisory Board (Mater. Today Phys.)

2021/06 - Present
日本熱電学会　評議員

2020/09 - Present
応用物理学会東北支部　企画運営委員

2019/04 - Present
APAC-Silicide 2025 現地実行委員

2024/05 - 2025/07
International Thermoelectric Society　Local Organizer

2020/11 - 2025/06
文部科学省　令和4年度専門調査員

2022/04 - 2023/03
東北大学　東北大学材料科学世界トップレベル研究拠点「東北大学材料科学フェスタ」実行委員

2022/07 - 2022/09
日本熱電学会　日本熱電学会選挙管理委員

2022/01 - 2022/09
応用物理学会　第83回応用物理学会秋季学術講演会実行委員

2021/06 - 2022/09
文部科学省　令和3年度専門調査員

2021/04 - 2022/03
文部科学省　令和2年度専門調査員

2020/04 - 2021/03
文部科学省　令和元年度専門調査員

2019/07 - 2020/03
応用物理学会東北支部　企画運営委員会幹事

2016/04 - 2019/03
応用物理学会東北支部　応用物理学会東北支部学術講演会現地実行委員

2018/11 - 2019/01
日本熱電学会　日本熱電学会学術講演会現地実行委員

2018/01 - 2018/09
応用物理学会　代議員

2014/02 - 2018/03
応用物理学会東北支部　応用物理学会東北支部学術講演会実行委員

2017/11 - 2018/01
応用物理学会　プログラム委員(9.4熱電変換)

2015/05 - 2017/09
応用物理学会東北支部　応用物理学会東北支部学術講演会現地実行委員

2016/11 - 2017/01
応用物理学会東北支部　企画運営委員

2012/08 - 2016/03
International Thermoelectric Society　Organizing Committee (Scientific Program)

2013/01 - 2013/07
日本熱電学会　広報委員

2010/10 - 2012/09
応用物理学会　応用物理学会学術講演会現地実行委員

2011/08 - 2011/09
日本熱電学会　日本熱電学会学術講演会現地実行委員

2009/01 - 2009/08

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Professional Memberships 7

The Professional Group of Semiconducting Silicides and Related Materials

2022/09 - Present
The Japan Institute of Metals and Materials

2021/04 - Present
International Thermoelectric Society

2013/01 - Present
The Thermoelectrics Society of Japan

2009/01 - Present
The Japan Society of Applied Physics

2005/11 - Present
日本物理学会

1997/04 - Present
The Waste Heat Recovery technology consortium of Japan

2024/02 - 2025/03

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Research Interests 5

semiconductors
Pyroelectric materials
Photovoltaic materials
Thermoelectric materials
Energy harvesting

Research Areas 4

Nanotechnology/Materials / Inorganic compounds/materials chemistry /
Nanotechnology/Materials / Composite materials and interfaces /
Nanotechnology/Materials / Thin-film surfaces and interfaces /
Nanotechnology/Materials / Crystal engineering /

Awards 39

The 29th The Japan Society of Applied Physics Tohoku Chapter Presentation Award

2025/01　The Japan Society of Applied Physics Tohoku Chapter　Data-driven approach for potential half-Heusler thermoelectrics with chemical bonding characteristics
フォレスト賞 (若手の優秀ポスター賞)

2024/09　光電子ホログラフィーとガンマ線誘起陽電子消滅寿命分光によって調べたMg2Sn結晶のアンチモン添加効果III
The ICT2024 Outstanding Poster Prize

2024/07　First-Principles Study for High Thermoelectric Performance Iron-based Half Heusler Compounds with Thermodynamic and Mechanical Stability
Outstanding Poster Presentation

2023/09　The European Thermoelectric Society　Preparation and thermoelectric properties of nonstoichiometric full‐Heusler Mn2+xV1-xAl alloys
Front cover (ACS Applied Energy Materials)

2023/04　ACS Publications　Charge-Compensated (V, Ru) Co-Substitution in Higher Manganese Silicide Single Crystals for Enhanced Thermoelectric and Mechanical Performance
第26回応用物理研究奨励賞

2023/03　東北大学大学院工学研究科応用物理学専攻
Back cover (Journal of Materials Chemistry A)

2023/02　Royal Society of Chemistry　Enhanced thermoelectric performance of p-type Mg2Sn single crystals via multi-scale defect engineering
工学研究科長賞

2021/03　東北大学大学院工学研究科
第24回応用物理研究奨励賞

2021/03　東北大学大学院工学研究科応用物理学専攻
The Best Poster Presentation

2020/12　Thai Thermoelectric Society (TTS) and Asian Association of Thermoelectrics (AAT)　Preparation, crystal structure and thermoelectric performance of p-type quaternary half-Heusler Ti(Fe0.5+xNi0.5-x)Sb compounds
Front cover (Journal of Materials Chemistry C)

2020/07　Royal Society of Chemistry　Crystal structure, electronic structure and thermoelectric properties of β- and γ-Zn4Sb3 thermoelectrics: a (3 + 1)-dimensional superspace group approach, Journal of Materials Chemistry C 8, 9205-9212 (2020).
第16回日本熱電学会学術講演会優秀ポスター賞

2019/09　日本熱電学会　C40型(Mn,Cr)(Si,Al)2系化合物における熱電特性の組成および合成条件依存性
38th International and 4th Asian Conference on Thermoelectrics Poster Award

2019/07　International Thermoelectric Society
応用物理学会東北支部特別賞

2018/12　応用物理学会東北支部
Outstanding Contribution in Reviewing (Chinese Journal of Physics)

2018/11　Elsevier
37th International and 16th European Conference on Thermoelectrics Poster Award

2018/07　International Thermoelectric Society
Back Picture (physica status solidi (a))

2018/06　Wiley　Pyroelectric Energy Harvesting Using Ferroelectric Ba1-xCaxTiO3, Physica Status Solidi (a), 215, 1701002 (2018).
Outstanding Contribution in Reviewing (Journal of Physics and Chemistry of Solids)

2018/06　Elsevier
Selected for Back Picture in Physica Status Solidi (a)

2018/06　Wiley Online Library　”Pyroelectric Energy Harvesting Using Ferroelectric Ba1−xCaxTiO3”, Physica Status Solidi (a), 215, 1701002 (2018).
第14回日本熱電学会学術講演会優秀ポスター賞

2017/09　Thermoelectric Properties of TiNiSi-based Solid Solutions
Outstanding Contribution in Reviewing (Journal of Alloys and Compounds)

2017/08　Elsevier
第20回応用物理研究奨励賞

2017/03　東北大学大学院工学研究科応用物理学専攻
第13回日本熱電学会学術講演会優秀ポスター賞

2016/09　日本熱電学会　還元拡散法を用いたCrSi2およびMo置換CrSi2の合成と熱電特性
日本金属学会 2016年秋季講演大会第27回優秀ポスター賞

2016/09　日本金属学会　単結晶X線回折を用いたMg2Si1-xSnxにおける格子間Mgの定量的評価
Featured Articles(Advances in Engineering)に選出

2016/09　Advances in Engineering　"Effect of Interstitial Mg in Mg2+xSi on Electrical Conductivity and Seebeck Coefficient", Journal of Electronic Materials, 45, 1589 (2016).
第70回応用物理学会東北支部学術講演会講演奨励賞

2016/01　応用物理学会東北支部　Mg2Si熱電材料におけるホウ素添加効果
第76回応用物理学会秋季学術講演会 Poster Award

2015/09　応用物理学会　ホウ素添加によるMg2Siの熱電特性向上と結晶構造
34th Annual International Conference on Thermoelectrics 2015 ITS Poster Award

2015/07　International Thermoelectric Society　Fabrication and Power Generation of a Silicide-based Thermoelectric Module
第68回応用物理学会東北支部学術講演会支部講演奨励賞

2013/12　応用物理学会東北支部　チムニーラダー型RhGeγ(γ ～ 1.294)の合成と熱電特性
Featured Articles(Advances in Engineering)に選出

2013/12　Advances in Engineering　"Crystal structure and thermoelectric properties of misfit-layered sulfides [Ln2S2]pNbS2 (Ln=Lanthanides)", Journal of Electronic Materials, 42, 1335 (2013).
Tohoku University's Chemistry Summer School 2013, Poster Award

2013/08
The 32nd International Conference on Thermoelectrics Portopia Award

2013/07　International Thermoelectric Society　Quantitative analysis of interstitial Mg in Mg2Si studied by single crystal X-ray diffraction
第59回応用物理学関係連合講演会第32回(2012年春季)応用物理学会講演奨励賞

2012/05　応用物理学会　p型シリサイド系熱電材料MnSiγ (γ~1.7)へのCr置換効果
第14回応用物理研究奨励賞

2011/03
工学研究科長賞

2011/03
第7回日本熱電学会学術講演会講演奨励賞

2010/08　日本熱電学会　PLD法により成膜したマンガンシリサイド薄膜の熱電特性
第6回日本熱電学会学術講演会講演奨励賞(ポスター発表の部)

2009/08　日本熱電学会　ラビング基板上に成膜したTTF-TCNQ薄膜の膜構造と熱電特性
日本表面科学会論文賞

2008/11　日本表面科学会　レーザー光電子スペクトル中に現れる振動励起非弾性構造, 表面科学 28, 378, (2007).
International Symposium on Innovative Materials for Processes in Energy Systems, Excellent Poster Presentation Award

2007/10　International Symposium on Innovative Materials for Processes in Energy Systems, Excellent Poster Presentation Award　Thermoelectric properties of delafossite-type oxide CuFe1-xNixO2 (0≤x≤0.05)

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Papers 118

Research Progress on Mn-based and Co-based Full-Heusler Alloys International-journal International-coauthorship Peer-reviewed

Hezhang Li, Md All Amin Newton, Chen Chen, Zhicheng Huang, Kei Hayashi, Yuzuru Miyazaki, Jing-Feng Li, Chao Wang

Solid State Sciences　108019　2025/07/11
Publisher: Elsevier
DOI： 10.1016/j.solidstatesciences.2025.108019 　
Data-driven approach for potential iron-based half-Heusler thermoelectrics with chemical bonding characteristics International-journal Peer-reviewed

Xue Nan, Kei Hayashi, Zhicheng Huang, Yuzuru Miyazaki

Science Advances　11　eadw4514　2025/06/27
Publisher: Science
Dislocation Introduction via Domain Engineering in Mg₂Sn Single Crystal to Improve its Thermoelectric Properties International-journal International-coauthorship Peer-reviewed

Zhicheng Huang, Kei Hayashi, Wataru Saito, Hezhang Li, Jun Pei, Jinfeng Dong, Toshiaki Chiba, Xue Nan, Bo‐Ping Zhang, Jing‐Feng Li, Yuzuru Miyazaki

Small Methods　2025/03/26
Publisher: Wiley
DOI： 10.1002/smtd.202500385 　

ISSN： 2366-9608

eISSN： 2366-9608

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Abstract Dislocations have increasingly become important for improving the thermoelectric properties of thermoelectric materials due to their more pronounced scattering effect on phonons than on carriers. This study combined the introduction of the dislocation cores through domain engineering with the generation of Mg vacancies (V_Mg) by controlling point defects to achieve low lattice thermal conductivity and high power factor in n‐type and p‐type Mg₂Sn single crystals (SCs). The V_Mg domain with ordered atomic arrangements allowed carrier transport with minimal scattering, while the high dislocation density at the interface effectively scattered phonons, thereby decoupling carrier‐phonon transport. This resulted in obtaining the peak zT values of 0.83(8) and 0.42(4) for n‐type and p‐type Mg₂Sn SCs, respectively. The outstanding combination of domain engineering and point defect control techniques could be a strategy for developing high‐performance thermoelectric materials.
Ultralow thermal conductivity and high ZT of Cu2Se-based thermoelectric materials mediated by TiO2−n nanoclusters International-journal International-coauthorship Peer-reviewed

Jincheng Yu, Xiaodong Liu, Haihua Hu, Yilin Jiang, Hua-Lu Zhuang, Hezhang Li, Bin Su, Jing-Wei Li, Zhanran Han, Zhengqin Wang, Lu Chen, Kei Hayashi, Yuzuru Miyazaki, B. Layla Mehdi, Jing-Feng Li

Joule　2024/07/01

DOI： 10.1016/j.joule.2024.06.007 　
Sr-Substitution Effects on Crystal Structure and Thermoelectric Properties of Misfit Layered Cobaltate, [Ca2CoO3] CoO2 International-journal Peer-reviewed

Y. Shimizu, K. Hayashi, Y. Miyazaki

Solid State Sciences　152　107536-107536　2024/06
Publisher: Elsevier BV
DOI： 10.1016/j.solidstatesciences.2024.107536 　

ISSN： 1293-2558
Enhancement of the thermoelectric performance of half-metallic full-Heusler Mn2VAl alloys via antisite defect engineering and Si partial substitution International-journal International-coauthorship Peer-reviewed

Hezhang Li, Kei Hayashi, Zhicheng Huang, Hiroto Takeuchi, Gakuto Kanno, Jing-Feng Li, Yuzuru Miyazaki

Journal of Materiomics　10　(2)　511-519　2024/03
Publisher: Elsevier BV
DOI： 10.1016/j.jmat.2023.11.013 　

ISSN： 2352-8478
Graphene-assisted synergistic electronic DOS modulation and phonon scattering to improve the thermoelectric performance of Mg₃Sb₂-based materials International-coauthorship Peer-reviewed

Qiang Zhang, Jiadang Li, Nagendra S. Chauhan, Lifei Wang, Zhicheng Huang, Wenhao Fan, Kei Hayashi, Shaoping Chen, Jianfeng Fan, Yuzuru Miyazaki

Journal of Materials Chemistry A　11　(35)　18811-18819　2023/08/10
Publisher: Royal Society of Chemistry (RSC)
DOI： 10.1039/d3ta02431h 　

ISSN： 2050-7488

eISSN： 2050-7496

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A large electronic density of states (DOS) coupled with homogeneous charge distribution can effectively improve the electrical conductivity σ and thus, the thermoelectric figure of merit ZT.
Bi‐Deficiency Leading to High‐Performance in Mg₃(Sb,Bi)₂‐Based Thermoelectric Materials International-journal International-coauthorship Peer-reviewed

Jing‐Wei Li, Weishu Liu, Wei Xu, Hua‐Lu Zhuang, Zhijia Han, Feng Jiang, Peng Zhang, Haihua Hu, Hanbin Gao, Yilin Jiang, Bowen Cai, Jun Pei, Bin Su, Qian Li, Kei Hayashi, Hezhang Li, Yuzuru Miyazaki, Xingzhong Cao, Qiang Zheng, Jing‐Feng Li

Advanced Materials　35　(23)　2209119　2023/04/25
Publisher: Wiley
DOI： 10.1002/adma.202209119 　

ISSN： 0935-9648

eISSN： 1521-4095

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Mg3(Sb,Bi)2 is a potential nearly-room temperature thermoelectric compound composed of earth-abundant elements. However, complex defect tuning and exceptional microstructural control are required. Prior studies have confirmed the detrimental effect of Mg vacancies (VMg) in Mg3(Sb,Bi)2. This study proposes an approach to mitigating the negative scattering effect of VMg by Bi deficiency, synergistically modulating the electrical and thermal transport properties to enhance the thermoelectric performance. Positron annihilation spectrometry and Cs-corrected scanning transmission electron microscopy analyses indicated that the VMg tends to coalesce due to the introduced Bi vacancies (VBi). The defects created by Bi deficiency effectively weaken the scattering of electrons from the intrinsic VMg and enhance phonon scattering. A peak zT of 1.82 at 773 K and high conversion efficiency of 11.3% at ∆T = 473 K are achieved in the optimized composition of Mg3(Sb,Bi)2 by tuning the defect combination. This work demonstrates a feasible and effective approach to improving the performance of Mg3(Sb,Bi)2 as an emerging thermoelectric material.
Effects of Oxygen on Lattice Defects in Single-Crystalline Mg2Si Thermoelectrics International-journal Peer-reviewed

Kei Hayashi, Sota Kawamura, Yusuke Hashimoto, Noboru Akao, Zhicheng Huang, Wataru Saito, Kaichi Tasaki, Koichi Hayashi, Tomohiro Matsushita, Yuzuru Miyazaki

Nanomaterials　13　(7)　1222-1222　2023/03/30
Publisher: MDPI AG
DOI： 10.3390/nano13071222 　

eISSN： 2079-4991

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Lattice defect engineering has attracted attention due to its ability to develop thermoelectric materials with low thermal conductivity. For Mg2Si single crystals (SCs), Si vacancy (VSi) defects can be introduced and consequently result in the formation of dislocation cores. These lattice defects confer Mg2Si SCs with a lower thermal conductivity compared to Mg2Si polycrystals. To reveal a mechanism for the stabilisation of VSi in the Mg2Si SCs, we investigated the effects of oxygen (O) on lattice defects by performing electronic structure calculations, secondary ion mass spectrometry, X-ray photoelectron spectroscopy, and photoelectron holography. On the basis of these calculations, we predicted that O stabilised the formation of VSi when it was located at the Si site or at an interstitial site. All experiments confirmed the presence of O inside the Mg2Si SCs. However, O was suggested to be located not at the specific site in the crystal lattice of Mg2Si but at dislocation cores. The interaction between O and the dislocation cores in the Mg2Si SC is expected to immobilise dislocation cores, leading to the stabilisation of VSi formation.
Charge-Compensated (V, Ru) Co-Substitution in Higher Manganese Silicide Single Crystals for Enhanced Thermoelectric and Mechanical Performance International-journal Peer-reviewed

Nagendra Singh Chauhan, Ichiro Ono, Kei Hayashi, Yuzuru Miyazaki

ACS Applied Energy Materials　6　(7)　3714-3723　2023/03/15
Publisher: American Chemical Society (ACS)
DOI： 10.1021/acsaem.2c03803 　

ISSN： 2574-0962

eISSN： 2574-0962

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Higher manganese silicides (HMSs) represented as MnSiγ are generically Nowotny chimney–ladder (NCL) compounds that obey the 14-electron rule due to which their stability and electrical properties are intimately related to the valence electron count (VEC) per number of transition metal atoms. However, owing to the incommensurate composite crystal structure of HMS, most doping/substitution approaches aimed at carrier concentration optimization had remained skewed, leading to limited control over its VEC. In this study, we propose the compensated co-substitution approach for the optimization of thermoelectric properties in NCL phases and demonstrate its efficacy by the co-substitution of the [Mn] subsystem with aliovalent V (p-type) and Ru (n-type) dopants in partially substituted (Mn1–x–yVxRuy)Siγ single crystals melt grown by the Bridgman method. The modulation vector component (γ) was accurately determined by the Le Bail analysis of the diffraction pattern using a (3 + 1) dimensional superspace approach and is correlated with the electrical transport and VEC of the synthesized samples. A remarkable enhancement in thermoelectric and mechanical performance was attained for the HMS single crystals upon (V, Ru) co-substitution in the direction perpendicular to the c-axis, i.e., along the cleavage plane. The charge compensation and synergistic reduction in lattice thermal conductivity thus result in a peak thermoelectric figure of merit (zT) of ∼0.6 (±0.1) at 823 K, which corresponds to ∼250% enhancement when compared to the pristine HMS single crystal.
Anisotropic correlations in higher manganese silicides International-journal Peer-reviewed

Nagendra S. Chauhan, Ichiro Ono, Kei Hayashi, Yuzuru Miyazaki

Journal of Alloys and Compounds　935　167983-167983　2023/02
Publisher: Elsevier BV
DOI： 10.1016/j.jallcom.2022.167983 　

ISSN： 0925-8388
Enhanced thermoelectric performance of p-type Mg2Sn single crystals via multi-scale defect engineering International-journal International-coauthorship Peer-reviewed

Zhicheng Huang, Kei Hayashi, Wataru Saito, Jun Pei, Jing-Feng Li, Yuzuru Miyazaki

Journal of Materials Chemistry A　11　2652-2660　2022/12/23
Publisher: Royal Society of Chemistry (RSC)
DOI： 10.1039/D2TA08557G 　

ISSN： 2050-7488

eISSN： 2050-7496

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Mg2Sn is a promising mid-temperature thermoelectric (TE) material consisting of earth-abundant, low-cost, and non-toxic elements. Currently, the TE performance of p-type Mg2Sn is still poor due to a lower power factor (PF) and a higher lattice thermal conductivity (κlat) than those of n-type Mg2Sn. To overcome these disadvantages, we synthesized Li-doped Mg2Sn single crystals (SCs) by the melting method. Li-doping successfully changed the conduction of the Mg2Sn SC from an n-type to a p-type. The Li-doped Mg2Sn SCs contain Mg vacancies, dislocation cores, and Sn-rich precipitates. These multi-scale defects in the Li-doped Mg2Sn SCs did not deteriorate carrier mobility and they effectively scattered phonons with a wide range of frequencies. Since grain boundaries did not exist in the Li-doped Mg2Sn SCs, higher carrier mobility and PF were achieved compared with other p-type Mg2Sn polycrystals (PCs) and SCs. Moreover, the κlat of the Li-doped Mg2Sn SC was lower than that of p-type Mg2Sn PCs and SCs. Owing to the enhanced PF and reduced κlat, a maximum dimensionless figure-of-merit zT of ∼0.38 at 700 K was achieved for the p-type Li-doped Mg2Sn SC with a Li content of 2.5%, the highest value for a p-type Mg2Sn ever reported.
Relevance of Solidification Kinetics for Enhanced Thermoelectric Performance in Al-Doped Higher Manganese Silicides International-journal Peer-reviewed

Nagendra S. Chauhan, Ichiro Ono, Kei Hayashi, Yuzuru Miyazaki

ACS Applied Materials & Interfaces　14　(46)　51983-51993　2022/11/23
Publisher: American Chemical Society (ACS)
DOI： 10.1021/acsami.2c16107 　

ISSN： 1944-8244

eISSN： 1944-8252
Enhancement of thermoelectric properties at room temperature through isoelectronic ruthenium-substitution in n-type half-Heusler VFeSb compounds International-journal Peer-reviewed

Yi Huang, Kei Hayashi, Yuzuru Miyazaki

Acta Materialia　237　118186-118186　2022/09
Publisher: Elsevier BV
DOI： 10.1016/j.actamat.2022.118186 　

ISSN： 1359-6454
Realizing p-type Mg2Sn Thermoelectrics via Ga-Doping and Point Defect Engineering Peer-reviewed

Zhicheng Huang, Kei Hayashi, Wataru Saito, Yuzuru Miyazaki

ACS Applied Energy Materials　4　(11)　13044-13050　2021/11/22
Publisher: American Chemical Society ({ACS})
DOI： 10.1021/acsaem.1c02678 　

ISSN： 2574-0962

eISSN： 2574-0962

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Mg2Sn is a promising middle-temperature thermoelectric material consisting of earth-abundant, low-cost, and nontoxic elements. To obtain p-type Mg2Sn, a series of Mg2Sn1–xGax (x = 0, 0.005, 0.01, 0.02, and 0.03) ingots were synthesized by melting them under an Ar atmosphere. It was found that the ingots with x ≤ 0.02 were single crystals with Mg vacancies (VMg) as point defects. Ga doping increased chemical pressure, leading to an increase in the VMg fraction, and it also introduced hole carriers in Mg2Sn, which changed its conduction type from n-type to p-type. A maximum zT value of 0.18 at 450 K was obtained for p-type Mg2Sn0.98Ga0.02 single crystals, which had a lower total thermal conductivity than some other p-type Mg2Sn-based polycrystals.
Crystal structure, microstructure, and electronic transport properties of β-Zn4Sb3 thermoelectrics: effects of Zn intercalation and deintercalation International-journal Peer-reviewed

S. Yoshioka, K. Hayashi, A. Yokoyama, W. Saito, Y. Miyazaki

Materials Today Energy　21　100723-100723　2021/09
Publisher: Elsevier BV
DOI： 10.1016/j.mtener.2021.100723 　

ISSN： 2468-6069

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The development of thermoelectric (TE) materials is the key to reduce the use of fossil fuels because they can reuse waste heat to generate electricity via the Seebeck effect. One of the promising p-type TE materials is β-Zn4Sb3 which exhibits high TE efficiency. To further improve its TE efficiency, β-Zn4Sb3 samples have been prepared by melting and subsequently heating them for different heating time. For the heating time below 150 h, intercalation of Zn atoms into the Zn interstitial (Zni) site of β-Zn4Sb3 occurs. In addition, the amount of Zn and Zn3Sb2 secondary phases decreases, yielding crack-free β-Zn4Sb3 samples. For the heating time above 150 h, deintercalation of Zn atoms from the Zni site of β-Zn4Sb3 occurs. Here, we discuss the evolution of the microstructure and the electronic transport properties, electrical conductivity and Seebeck coefficient (thermopower), during heating from the viewpoint of the Zn intercalation and deintercalation, and this enables us to propose an optimal condition for preparing β-Zn4Sb3 with high TE efficiency.
Outstanding thermoelectric performance of n-type half-Heusler V(Fe1−xCox)Sb compounds at room-temperature Peer-reviewed

Yi Huang, Kei Hayashi, Yuzuru Miyazaki

Acta Materialia　215　117022-117022　2021/08

DOI： 10.1016/j.actamat.2021.117022 　

ISSN： 1359-6454

eISSN： 1873-2453
Chemical-Pressure-Induced Point Defects Enable Low Thermal Conductivity for Mg2Sn and Mg2Si Single Crystals International-journal Peer-reviewed

Wataru Saito, Kei Hayashi, Zhicheng Huang, Kazuya Sugimoto, Kenji Ohoyama, Naohisa Happo, Masahide Harada, Kenichi Oikawa, Yasuhiro Inamura, Kouichi Hayashi, Takamichi Miyazaki, Yuzuru Miyazaki

ACS Applied Energy Materials　4　(5)　5123-5131　2021/05/24
Publisher: American Chemical Society ({ACS})
DOI： 10.1021/acsaem.1c00670 　

ISSN： 2574-0962

eISSN： 2574-0962
Enhanced thermoelectric performance in MnTe due to doping and in-situ nanocompositing effects by Ag2S addition International-journal International-coauthorship Peer-reviewed

Jinfeng Dong, Jun Pei, Kei Hayashi, Wataru Saito, Hezhang Li, Bowen Cai, Yuzuru Miyazaki, Jing-Feng Li

Journal of Materiomics　7　(3)　577-584　2021/05
Publisher: Elsevier {BV}
DOI： 10.1016/j.jmat.2020.11.007 　

ISSN： 2352-8478
Effects of Disorder on the Electronic Structure and Thermoelectric Properties of an Inverse Full-Heusler Mn2CoAl Alloy Peer-reviewed

Hezhang Li, Kei Hayashi, Yoshimi Nagashima, Shun Yoshioka, Jinfeng Dong, Jing-Feng Li, Yuzuru Miyazaki

Chemistry of Materials　33　(7)　2543-2547　2021/04/13
Publisher: American Chemical Society ({ACS})
DOI： 10.1021/acs.chemmater.0c04902 　

ISSN： 0897-4756

eISSN： 1520-5002

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We report a detailed analysis of the crystal structure, electronic structure, and thermoelectric (TE) properties of a stoichiometric Mn2CoAl inverse full-Heusler alloy, which has been predicted to be a spin-gapless semiconductor. To reveal the effects of disorder on TE properties (electrical conductivity and Seebeck coefficient), we prepared Mn2Co(Al1–xSix) (x = 0, 0.05, and 0.1) bulk samples by arc melting. The crystal structure analysis indicates that antisite defects exist in the prepared samples. From the measurements of the electrical conductivity and Seebeck coefficient, it is demonstrated that the prepared Mn2CoAl alloy is not a spin-gapless semiconductor but a half-metal. A relation between the crystal structure and TE properties is discussed based on the calculation of the electronic structure considering the antisite defects in Mn2CoAl.
Relationships between crystallite size and thermoelectric properties of nano-structured CrSi2 prepared by the reduction-diffusion and spark plasma sintering methods Peer-reviewed

Hayato Nakasawa, Tomohisa Takamatsu, Kei Hayashi, Yuzuru Miyazaki

Journal of Alloys and Compounds　861　157967-157967　2021/04
Publisher: Elsevier BV
DOI： 10.1016/j.jallcom.2020.157967 　

ISSN： 0925-8388
Erratum: “Preparation, thermoelectric properties, and crystal structure of boron-doped Mg2Si single crystals” [AIP Advances 10, 035115 (2020)]

Kei Hayashi, Wataru Saito, Kazuya Sugimoto, Kenji Ohoyama, Kouichi Hayashi, Naohisa Happo, Masahide Harada, Kenichi Oikawa, Yasuhiro Inamura, Yuzuru Miyazaki

AIP Advances　11　(2)　029903-029903　2021/02/01
Publisher: {AIP} Publishing
DOI： 10.1063/5.0045729 　
Enhancing the Thermoelectric Performance of Mg2Sn Single Crystals via Point Defect Engineering and Sb Doping International-journal International-coauthorship Peer-reviewed

Wataru Saito, Kei Hayashi, Zhicheng Huang, Jinfeng Dong, Jing-Feng Li, Yuzuru Miyazaki

ACS Applied Materials & Interfaces　12　(52)　57888-57897　2020/12/30
Publisher: American Chemical Society ({ACS})
DOI： 10.1021/acsami.0c17462 　

ISSN： 1944-8244

eISSN： 1944-8252
Electron Conduction Mechanism of Deficient Half-Heusler VFeSb Compound Revealed by Crystal and Electronic Structure Analyses Peer-reviewed

Yi Huang, Kei Hayashi, Yuzuru Miyazaki

Chemistry of Materials　32　(12)　5173-5181　2020/06/23
Publisher: American Chemical Society (ACS)
DOI： 10.1021/acs.chemmater.0c01189 　

ISSN： 0897-4756

eISSN： 1520-5002
Crystal structure, electronic structure and thermoelectric properties of β- and γ-Zn4Sb3 thermoelectrics: a (3 + 1)-dimensional superspace group approach Peer-reviewed

Shun Yoshioka, Kei Hayashi, Aisaku Yokoyama, Wataru Saito, Hezhang Li, Tomohisa Takamatsu, Yuzuru Miyazaki

Journal of Materials Chemistry C　8　(27)　9205-9212　2020/06/05
Publisher: Royal Society of Chemistry (RSC)
DOI： 10.1039/d0tc01497d 　

ISSN： 2050-7526

eISSN： 2050-7534

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<p>Using a (3 + 1)-dimensional ((3 + 1)-D) superspace group approach, a composite crystal structure model for β- and γ-phases of Zn₄Sb₃ is constructed. Intercalation of Zn atoms into the Zn_i site is found, which affects thermoelectric properties.</p>
Distinct impact of order degree on thermoelectric power factor of p-type full-Heusler Mn2VAl compounds International-coauthorship Peer-reviewed

Hezhang Li, Kei Hayashi, Jinfeng Dong, Jing-Feng Li, Yuzuru Miyazaki

Materials Research Express　7　(5)　055503-055503　2020/05/01
Publisher: IOP Publishing
DOI： 10.1088/2053-1591/ab875b 　

eISSN： 2053-1591
Preparation, thermoelectric properties, and crystal structure of boron-doped Mg2Si single crystals Peer-reviewed

Kei Hayashi, Wataru Saito, Kazuya Sugimoto, Kenji Ohoyama, Kouichi Hayashi, Naohisa Happo, Masahide Harada, Kenichi Oikawa, Yasuhiro Inamura, Yuzuru Miyazaki

AIP Advances　10　(3)　035115-035115　2020/03/01
Publisher: {AIP} Publishing
DOI： 10.1063/1.5143839 　

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Mg2Si is a potential thermoelectric (TE) material that can directly convert waste energy into electricity. In expectation of improving its TE performance by increasing electron carrier concentration, the element boron (B) is doped in Mg2Si single crystals (SCs). Their detailed crystal structures are definitely determined by using white neutron holography and single-crystal x-ray diffraction (SC-XRD) measurements. The white neutron holography measurement proves that the doped B atom successfully substitutes for the Mg site. The SC-XRD measurement confirms the B-doping site and also reveals the presence of the defect of Si vacancy (VSi) in the B-doped Mg2Si SCs. The fraction of VSi increases with increasing B-doping concentration. In the case of B-doped Mg2Si polycrystals (PCs), VSi is absent; this difference between the SCs and PCs can be attributed to different preparation temperatures. Regarding TE properties, the electrical conductivity, σ, and the Seebeck coefficient, S, decreases and increases, respectively, due to the decrease in the electron carrier concentration, contrary to the expectation. The power factor of the B-doped Mg2Si SCs evaluated from σ and S does not increase but rather decreases by the B-doping. The tendencies of these TE properties can be explained by considering that the donor effect of the B atom is canceled by the acceptor effect of VSi for the B-doped Mg2Si SCs. This study demonstrates that the preparation condition of Mg2Si should be optimized to prevent the emergence of an unexpected point defect.
Control of the Thermoelectric Properties of Mg2Sn Single Crystals via Point-Defect Engineering International-journal International-coauthorship Peer-reviewed

Kei Hayashi

Scientific Reports　10　2020　2020/02/06

DOI： 10.1038/s41598-020-58998-1 　

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Mg2Sn is a potential thermoelectric (TE) material that can directly convert waste heat into electricity. In this study, Mg2Sn single-crystal ingots are prepared by melting under an Ar atmosphere. The prepared ingots contain Mg vacancies (VMg) as point defects, which results in the formation of two regions: an Mg2Sn single-crystal region without VMg (denoted as the single-crystal region) and a region containing VMg (denoted as the VMg region). The VMg region is embedded in the matrix of the single-crystal region. The interface between the VMg region and the single-crystal region is semi-coherent, which does not prevent electron carrier conduction but does increase phonon scattering. Furthermore, electron carrier concentration depends on the fraction of VMg, reflecting the acceptor characteristics of VMg. The maximum figure of merit zTmax of 1.4(1) × 10−2 is realised for the Mg2Sn single-crystal ingot by introducing VMg. These results demonstrate that the TE properties of Mg2Sn can be optimised via point-defect engineering.
Reducing Lattice Thermal Conductivity of MnTe by Se Alloying toward High Thermoelectric Performance International-coauthorship Peer-reviewed

Kei Hayashi

ACS Applied Materials & Interfaces　11　(31)　28221-28227　2019/08/07

DOI： 10.1021/acsami.9b10207 　

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Lead-free manganese telluride has been considered to be a promising candidate for mid-temperature thermoelectric materi-als. In this work, we report a point defect scattering induced reduction of thermal conductivity in MnTe with Se alloying, fabricated by a facile method combining mechanical alloying (MA) and spark plasma sintering (SPS). A low lattice thermal conductivity of 0.56 W/m-K was obtained for MnTe0.92Se0.08, which is quite close to the amorphous limits. A detailed Debye model analysis reveals the underlying mechanism of phonon scattering and well predicts the thermal conductivity with dif-ferent contents of Se. Meanwhile, a slight increase of carrier concentration was also observed after Se alloying, accompanying a variation of energy gap which may be associated with the competition of anion in trapping charges. Further Na doping leads to enhanced electrical transport properties, achieving a maximum ZT value of 1.03 at 873 K. An average ZT of 0.52 and a calculated efficiency over 9% also suggest the promising application of MnTe at medium temperature.
Design and power generation of tilted Cu/Fe₂V(Al_0.9Si_0.1) multilayers via the transverse thermoelectric effect Peer-reviewed

Naoto Kodaira, Yuzuru Miyazaki, Kei Hayashi

Journal of Applied Physics　126　(4)　045108-045108　2019/07
Publisher: AIP Publishing
DOI： 10.1063/1.5103226 　

ISSN： 0021-8979

eISSN： 1089-7550

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We have conducted a computer simulation of thermoelectric (TE) properties in tilted Cu/Fe2V(Al0.9Si0.1) multilayers. Such a tilted configuration yields a transverse (off-diagonal) TE effect whereby an electric current can flow perpendicularly to the temperature gradient. Appropriately controlling the relative Cu thickness and the tilting angle realizes a higher power factor than that of the parent TE materials. In our multilayers, the estimated power factor exceeds 8mW/K2m, being approximately three times higher than that of the parent TE materials. On the basis of the simulation results, we have fabricated several modules and achieved a maximum power of 4.83mW in the module with a relative Cu thickness of 0.7 and a tilting angle of 30°.
Lattice dynamics and lattice thermal conductivity of CrSi 2 calculated from first principles and the phonon Boltzmann transport equation Peer-reviewed

Nakasawa, H., Hayashi, K., Takamatsu, T., Miyazaki, Y.

Journal of Applied Physics　126　(2)　025105　2019/07

DOI： 10.1063/1.5096458 　
Effects of Cobalt Substitution on Crystal Structure and Thermoelectric Properties of Melt-Grown Higher Manganese Silicides Peer-reviewed

Nagai, H., Hamada, H., Hayashi, K., Miyazaki, Y.

Journal of Electronic Materials　48　(4)　1902-1908　2019/02

DOI： 10.1007/s11664-019-06958-5 　
Preparation and thermoelectric properties of pseudogap intermetallic (Ti_1-xV_x)NiSi solid solutions Peer-reviewed

Yi Huang, Hiroki Nagai, Kei Hayashi, Yuzuru Miyazaki

Journal of Alloys and Compounds　771　111-116　2019/01
Publisher: Elsevier BV
DOI： 10.1016/j.jallcom.2018.08.238 　

ISSN： 0925-8388

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We theoretically and experimentally investigated the thermoelectric (TE) properties of TiNiSi-based solid solutions with a pseudogap at the Fermi level in the electronic band structure. Calculation of the TE properties of TiNiSi predicted that electron doping of TiNiSi leads to a higher power factor than hole doping. According to this prediction, we prepared the partially V-substituted TiNiSi-based compounds (Ti1-xVx)NiSi (x = 0, 0.05, 0.10, 0.15, and 0.20) using arc-melting and subsequent spark plasma sintering. An increase in the V content x improved the n-type TE properties: the absolute values of the Seebeck coefficient and electrical conductivity both increased, while the thermal conductivity slightly decreased. The highest dimensionless figure-of-merit, zT, was 0.032 at 600 K, obtained for the x = 0.20 sample.
Preparation and optical properties of higher manganese silicide, (Mn,Fe)Si <inf>γ</inf> , thin films Peer-reviewed

Kei Hayashi, Kentaro Ishii, Chihiro Kawasaki, Ryosuke Honda, Yuzuru Miyazaki

Applied Surface Science　458　700-704　2018/11/15

DOI： 10.1016/j.apsusc.2018.07.141 　

ISSN： 0169-4332
Improved thermoelectric performance from CrSi<inf>2</inf> by Cu substitution into Si sites Peer-reviewed

Nagai, H., Takamatsu, T., Iijima, Y., Hayashi, K., Miyazaki, Y.

Japanese Journal of Applied Physics　57　(12)　121801　2018/11/08

DOI： 10.7567/JJAP.57.121801 　
Fabrication and thermoelectric properties of Al/Mg<inf>2</inf>Si composite materials Peer-reviewed

Hayashibara, Y., Hayashi, K., Ando, I., Kubouchi, M., Ogawa, Y., Saito, W., Miyazaki, Y.

Materials Transactions　59　(7)　1041-1045　2018/07

DOI： 10.2320/matertrans.E-M2018815 　
Pyroelectric Energy Harvesting Using Ferroelectric Ba1−xCaxTiO3 Peer-reviewed

Kei Hayashi, Eisuke Aikawa, Toru Ueno, Tsuyoshi Kajitani, Yuzuru Miyazaki

Physica Status Solidi (A) Applications and Materials Science　215　(11)　1701002/1-1701002/5　2018/06/06
Publisher: Wiley-VCH Verlag
DOI： 10.1002/pssa.201701002 　

ISSN： 1862-6319 1862-6300
Design and fabrication of full-Heusler compound with positive Seebeck coefficient as a potential thermoelectric material Peer-reviewed

Hezhang Li, Kei Hayashi, Yuzuru Miyazaki

Scripta Materialia　150　130-133　2018/06/01
Publisher: Acta Materialia Inc
DOI： 10.1016/j.scriptamat.2018.03.018 　

ISSN： 1359-6462
Crystal structure and thermoelectric properties of lightly substituted higher manganese silicides Invited Peer-reviewed

Yuzuru Miyazaki, Haruki Hamada, Hiroki Nagai, Kei Hayashi

Materials　11　(6)　926/1-926/11　2018/05/30
Publisher: MDPI AG
DOI： 10.3390/ma11060926 　

ISSN： 1996-1944
Thermoelectric Properties of Mo and Ge co-substituted CrSi₂ Peer-reviewed

Kei Hayashi

Transactions of the Materials Research Society of Japan　43　(2)　85-91　2018/04

DOI： 10.14723/TMRSJ.43.85 　
Thermoelectric properties of olivine-type sulfides Tm₂XS₄ (Tm = Mn, Fe, X = Si, Ge) Peer-reviewed

Kei Hayashi

Transactions of the Materials Research Society of Japan　43　(1)　13-17　2018/02

DOI： 10.14723/TMRSJ.43.13 　

ISSN： 1382-3469
Pyroelectric Energy Harvesting Using Ferroelectric Ba _{1− x} Ca _x TiO ₃ (Phys. Status Solidi A 11∕2018)

Kei Hayashi

Physica Status Solidi (a)　2018

DOI： 10.1002/PSSA.201870023 　
Enhanced thermoelectric properties of chimney-ladder type higher manganese silicides Peer-reviewed

Yuzuru Miyazaki, Haruki Hamada, Yuta Kikuchi, Kei Hayashi

Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy　64　(8)　461-466　2017/08/01
Publisher: Journal of the Japan Society of Powder and Powder Metallurgy
DOI： 10.2497/jjspm.64.461 　

ISSN： 0532-8799
Preparation and thermoelectric properties of mixed valence compound Sn2S3 Peer-reviewed

Wataru Saito, Kei Hayashi, Hiroki Nagai, Yuzuru Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS　56　(6)　061201/1-061201/4　2017/06

DOI： 10.7567/JJAP.56.061201 　

ISSN： 0021-4922

eISSN： 1347-4065
Crystal Structure and Thermoelectric Properties of Lightly Vanadium-Substituted Higher Manganese Silicides (Mn1-x V (x) )Si (gamma) ) Peer-reviewed

Yuzuru Miyazaki, Haruki Hamada, Kei Hayashi, Kunio Yubuta

JOURNAL OF ELECTRONIC MATERIALS　46　(5)　2705-2709　2017/05

DOI： 10.1007/s11664-016-4937-z 　

ISSN： 0361-5235

eISSN： 1543-186X
Structural and Thermoelectric Properties of Ternary Full-Heusler Alloys Peer-reviewed

K. Hayashi, M. Eguchi, Y. Miyazaki

JOURNAL OF ELECTRONIC MATERIALS　46　(5)　2710-2716　2017/05

DOI： 10.1007/s11664-016-4944-0 　

ISSN： 0361-5235

eISSN： 1543-186X
Structural and thermoelectric properties of TTF-I-0.71 organic compound Peer-reviewed

Kei Hayashi, Kento Kuba, Yuzuru Miyazaki

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS　254　(2)　1600513/1-1600513/4　2017/02

DOI： 10.1002/pssb.201600513 　

ISSN： 0370-1972

eISSN： 1521-3951
Polymer electrolyte liquid crystal mixtures as phase-dependent thermoelectric materials International-journal International-coauthorship Peer-reviewed

Said, S.M., Sahamir, S.R., Sabri, M.F.M., Kamarudin, M.A., Hayashi, K., Zulkifli, A.Z.S., Nakajo, T., Kubouchi, M., Miyazaki, Y.

Molecular Crystals and Liquid Crystals　642　(1)　9-17　2017

DOI： 10.1080/15421406.2016.1262668 　
Effects of Nb substitution on thermoelectric properties of CrSi2 Peer-reviewed

Hiroki Nagai, Tomohisa Takamatsu, Yoshihiko Iijima, Kei Hayashi, Yuzuru Miyazaki

JOURNAL OF ALLOYS AND COMPOUNDS　687　37-41　2016/12

DOI： 10.1016/j.jallcom.2016.06.047 　

ISSN： 0925-8388

eISSN： 1873-4669
Effects of Ge substitution on thermoelectric properties of CrSi2 Peer-reviewed

Hiroki Nagai, Tomohisa Takamatsu, Yoshihiko Iijima, Kei Hayashi, Yuzuru Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS　55　(11)　111801　2016/11

DOI： 10.7567/JJAP.55.111801 　

ISSN： 0021-4922

eISSN： 1347-4065
Thermoelectric and magnetic properties of Yb2MgSi2 prepared by spark plasma sintering method Peer-reviewed

M. Kubouchi, K. Hayashi, Y. Miyazaki

APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING　122　(8)　769/1-769/6　2016/08

DOI： 10.1007/s00339-016-0300-8 　

ISSN： 0947-8396

eISSN： 1432-0630
Electronic structure and thermoelectric properties of boron doped Mg2Si Peer-reviewed

M. Kubouchi, K. Hayashi, Y. Miyazaki

SCRIPTA MATERIALIA　123　59-63　2016/06/10

DOI： 10.1016/j.scriptamat.2016.06.001 　

ISSN： 1359-6462
Thermoelectric Hexagonal A-Mg-Si with A = Sr and Ba Zintl Phases Peer-reviewed

T. Kajitani, K. Takahashi, M. Saito, H. Suzuki, S. Kikuchi, M. Kubouchi, K. Hayashi

JOURNAL OF ELECTRONIC MATERIALS　45　(10)　5238-5245　2016/06/03

DOI： 10.1007/s11664-016-4658-3 　

ISSN： 0361-5235

eISSN： 1543-186X
Crystal Structure and Thermoelectric Properties of the Incommensurate Chimney-Ladder Compound VGe gamma (gamma similar to 1.82) Peer-reviewed

Haruki Hamada, Yuta Kikuchi, Kei Hayashi, Yuzuru Miyazaki

JOURNAL OF ELECTRONIC MATERIALS　45　(3)　1365-1368　2016/03

DOI： 10.1007/s11664-015-4036-6 　

ISSN： 0361-5235

eISSN： 1543-186X
Effect of Interstitial Mg in Mg2+xSi on Electrical Conductivity and Seebeck Coefficient Peer-reviewed

M. Kubouchi, Y. Ogawa, K. Hayashi, T. Takamatsu, Y. Miyazaki

JOURNAL OF ELECTRONIC MATERIALS　45　(3)　1589-1593　2016/03

DOI： 10.1007/s11664-015-4126-5 　

ISSN： 0361-5235

eISSN： 1543-186X
Electronic transport properties in the undoped cuprate superconductor T'-La_1.8Eu_0.2CuO₄

Ohashi K., Kawamata T., Takamatsu T., Adachi T., Kato M., Naito S., Hayashi K., Miyazaki Y., Koike Y.

Meeting Abstracts of the Physical Society of Japan　71　1924-1924　2016
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.71.2.0_1924 　
Structural and thermoelectric properties of TTF-I-0.71 organic compound Peer-reviewed

Hayashi, Kei, Kuba, Kento, Miyazaki, Yuzuru, IEEE

2016 Compound Semiconductor Week (Csw) Includes 28th International Conference on Indium Phosphide & Related Materials (Iprm) & 43rd International Symposium on Compound Semiconductors (Iscs)　2016
Crystal structure and thermoelectric properties of the incommensurate chimney-ladder compound RhGe gamma (gamma similar to 1.293) Invited Peer-reviewed

Yuzuru Miyazaki, Takaki Nakajo, Yuta Kikuchi, Kei Hayashi

JOURNAL OF MATERIALS RESEARCH　30　(17)　2611-2617　2015/09

DOI： 10.1557/jmr.2015.137 　

ISSN： 0884-2914

eISSN： 2044-5326
Ionic liquid entrapment by an electrospun polymer nanofiber matrix as a high conductivity polymer electrolyte International-journal International-coauthorship Peer-reviewed

R. S. Datta, S. M. Said, S. R. Shahrir, Norbani Abdullah, M. F. M. Sabri, S. Balamurugan, Y. Miyazaki, K. Hayashi, N. A. Hashim, Umma Habiba, Amalina M. Afifi

RSC ADVANCES　5　(60)　48217-48223　2015

DOI： 10.1039/c5ra03935e 　

ISSN： 2046-2069
High temperature X-ray diffraction study on incommensurate composite crystal MnSi gamma - (3+1)-dimensional superspace approach Peer-reviewed

Y. Kikuchi, T. Nakajo, K. Hayashi, Y. Miyazaki

JOURNAL OF ALLOYS AND COMPOUNDS　616　263-267　2014/12

DOI： 10.1016/j.jallcom.2014.07.106 　

ISSN： 0925-8388

eISSN： 1873-4669
Quantitative analysis of interstitial Mg in Mg2Si studied by single crystal X-ray diffraction Peer-reviewed

M. Kubouchi, K. Hayashi, Y. Miyazaki

JOURNAL OF ALLOYS AND COMPOUNDS　617　389-392　2014/12

DOI： 10.1016/j.jallcom.2014.07.137 　

ISSN： 0925-8388

eISSN： 1873-4669
Microstructure and thermoelectric properties of y x Al y B14 samples fabricated through the spark plasma sintering Peer-reviewed

Satofumi Maruyama, Toshiyuki Nishimura, Yuzuru Miyazaki, Kei Hayashi, Tsuyoshi Kajitani, Takao Mori

Materials for Renewable and Sustainable Energy　3　(3)　31　2014/09/01
Publisher: SpringerOpen
DOI： 10.1007/s40243-014-0031-8 　

ISSN： 2194-1467 2194-1459

eISSN： 2194-1467
Fabrication of Multilayer-Type Mn-Si Thermoelectric Device Peer-reviewed

T. Kajitani, T. Ueno, Y. Miyazaki, K. Hayashi, T. Fujiwara, R. Ihara, T. Nakamura, M. Takakura

JOURNAL OF ELECTRONIC MATERIALS　43　(6)　1993-1999　2014/06

DOI： 10.1007/s11664-013-2933-0 　

ISSN： 0361-5235

eISSN： 1543-186X
Thermoelectric Potential of Polymer-Scaffolded Ionic Liquid Membranes International-journal International-coauthorship Peer-reviewed

R. S. Datta, S. M. Said, S. R. Sahamir, M. R. Karim, M. F. M. Sabri, T. Nakajo, M. Kubouchi, K. Hayashi, Y. Miyazaki

JOURNAL OF ELECTRONIC MATERIALS　43　(6)　1585-1589　2014/06

DOI： 10.1007/s11664-013-2799-1 　

ISSN： 0361-5235

eISSN： 1543-186X
Theoretical and experimental investigation of the excellent p-n control in yttrium aluminoborides Peer-reviewed

Ryoji Sahara, Takao Mori, Satofumi Maruyama, Yuzuru Miyazaki, Kei Hayashi, Tsuyoshi Kajitani

SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS　15　(3)　035012/1-035012/8　2014/06

DOI： 10.1088/1468-6996/15/3/035012 　

ISSN： 1468-6996

eISSN： 1878-5514
Al insertion and additive effects on the thermoelectric properties of yttrium boride Peer-reviewed

Satofumi Maruyama, Anastasiia Prytuliak, Yuzuru Miyazaki, Kei Hayashi, Tsuyoshi Kajitani, Takao Mori

JOURNAL OF APPLIED PHYSICS　115　(12)　123702/1-123702/6　2014/03

DOI： 10.1063/1.4869131 　

ISSN： 0021-8979

eISSN： 1089-7550
新規なホウ素系高温熱電変換材料の展望

森孝雄, David Berthebaud, Anastasiia Prytuliak, Ievgen Kuzmych-Ianchuk, Oksana Solohub, 西島一志, 道上勇一, 西村聡之, 丸山恵史, 宮崎譲, 林慶, 梶谷剛, 野村明子, 湯葢邦夫, 宍戸統悦, 岡田繁

第9回日本ホウ素・ホウ化物研究会　9　5-6　2013/12
High-Performance p-Type Magnesium Silicon Thermoelectrics Peer-reviewed

T. Kajitani, M. Kubouchi, S. Kikuchi, K. Hayashi, T. Ueno, Y. Miyazaki, K. Yubuta

JOURNAL OF ELECTRONIC MATERIALS　42　(7)　1855-1863　2013/07

DOI： 10.1007/s11664-012-2450-6 　

ISSN： 0361-5235
Crystal Structure and Thermoelectric Properties of Misfit-Layered Sulfides [Ln(2)S(2)] (p) NbS2 (Ln = Lanthanides) Peer-reviewed

Yuzuru Miyazaki, Hidenori Ogawa, Takaki Nakajo, Yuta Kikuchii, Kei Hayashi

JOURNAL OF ELECTRONIC MATERIALS　42　(7)　1335-1339　2013/07

DOI： 10.1007/s11664-012-2443-5 　

ISSN： 0361-5235

eISSN： 1543-186X
Structural, magnetic, and ferroelectric properties of CuFe1-xMnxO2 Peer-reviewed

K. Hayashi, R. Fukatsu, T. Nozaki, Y. Miyazaki, T. Kajitani

PHYSICAL REVIEW B　87　(6)　064418/1-064418/5　2013/02

DOI： 10.1103/PhysRevB.87.064418 　

ISSN： 1098-0121
特異な結晶構造を持つマンガンケイ化物系熱電材料の高性能化

宮﨑讓, 菊池祐太, 林慶

日本機械学会第5回マイクロ・ナノ工学シンポジウム講演論文集　2013
Excellent p-n control in a high temperature thermoelectric boride Peer-reviewed

Satofumi Maruyama, Yuzuru Miyazaki, Kei Hayashi, Tsuyoshi Kajitani, Takao Mori

APPLIED PHYSICS LETTERS　101　(15)　152101/1-152101/4　2012/10

DOI： 10.1063/1.4758297 　

ISSN： 0003-6951
Enhanced Thermoelectric Performance of a Chimney-Ladder (Mn1-xCrx)Si-gamma (gamma similar to 1.7) Solid Solution Peer-reviewed

Yuta Kikuchi, Yuzuru Miyazaki, Yoshitsugu Saito, Kei Hayashi, Kunio Yubuta, Tsuyoshi Kajitani

JAPANESE JOURNAL OF APPLIED PHYSICS　51　(8)　085801　2012/08

DOI： 10.1143/JJAP.51.085801 　

ISSN： 0021-4922
Anisotropic Thermoelectric Properties of MnSi gamma Film Prepared on R-Sapphire Peer-reviewed

Komei Takeda, Yuta Kikuchi, Kei Hayashi, Yuzuru Miyazaki, Tsuyoshi Kajitani

APPLIED PHYSICS EXPRESS　5　(5)　055501　2012/05

DOI： 10.1143/APEX.5.055501 　

ISSN： 1882-0778
Cation distribution dependence on thermoelectric properties of doped spinel M 0.6Fe 2.4O 4 Peer-reviewed

Tomohiro Nozaki, Kei Hayashi, Yuzuru Miyazaki, Tsuyoshi Kajitani

Materials Transactions　53　(6)　1164-1168　2012

DOI： 10.2320/matertrans.M2012023 　

ISSN： 1345-9678
Phase separation in thermoelectric delafossite CuFe1-xNixO2 observed by soft x-ray magnetic circular dichroism International-journal International-coauthorship Peer-reviewed

J. -S. Kang, D. H. Kim, Jihoon Hwang, Eunsook Lee, T. Nozaki, K. Hayashi, T. Kajitani, B. -G. Park, J. -Y. Kim, B. I. Min

APPLIED PHYSICS LETTERS　99　(1)　012108/1-012108/3　2011/07

DOI： 10.1063/1.3609248 　

ISSN： 0003-6951
Soft x-ray synchrotron radiation spectroscopy study of CuFe1-xNixO2 (0 <= x <= 0.03) delafossite oxides International-journal International-coauthorship Peer-reviewed

D. H. Kim, J. H. Hwang, K. H. Lee, J. -S. Kang, T. Nozaki, K. Hayashi, T. Kajitani, B. -G. Park, J. -Y. Kim, B. I. Min

JOURNAL OF APPLIED PHYSICS　109　(7)　07D727/1-07D727/3　2011/04

DOI： 10.1063/1.3561041 　

ISSN： 0021-8979
Preparation and Thermoelectric Properties of a Chimney-Ladder (Mn1-xFex)Si-gamma (gamma similar to 1.7) Solid Solution Peer-reviewed

Yuzuru Miyazaki, Yoshitsugu Saito, Kei Hayashi, Kunio Yubuta, Tsuyoshi Kajitani

JAPANESE JOURNAL OF APPLIED PHYSICS　50　(3)　035804/1-035804/5　2011/03

DOI： 10.1143/JJAP.50.035804 　

ISSN： 0021-4922
Fabrication of iodine-doped pentacene thin films for organic thermoelectric devices Peer-reviewed

K. Hayashi, T. Shinano, Y. Miyazaki, T. Kajitani

JOURNAL OF APPLIED PHYSICS　109　(2)　023712/1-023712/4　2011/01

DOI： 10.1063/1.3537831 　

ISSN： 0021-8979
Thermoelectric properties of iodine doped pentacene thin films Peer-reviewed

Kei Hayashi, Takashi Shinano, Yuzuru Miyazaki, Tsuyoshi Kajitani

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 8, NO 2　8　(2)　2011

DOI： 10.1002/pssc.201000425 　

ISSN： 1862-6351
Effect of Cobalt-Substitution on the Structure and Thermoelectric Properties of Chimney-Ladder Solid Solution (Mn1-xCox)Siγ (γ~1.7) Peer-reviewed

Y. Miyazaki, Y. Saito, K. Hayashi, K. Yubuta, T. Kajitani

Advances in Science and Technology　74　22-25　2010/10

DOI： 10.4028/www.scientific.net/AST.74.22 　
Thermoelectric iron oxides Peer-reviewed

T. Kajitani, T. Nozaki, K. Hayashi

Advances in Science and Technology　74　66-71　2010/10

DOI： 10.4028/www.scientific.net/AST.74.66 　
Mn-Substitution Effect on Thermal Conductivity of Delafossite-Type Oxide CuFeO2 Peer-reviewed

T. Nozaki, K. Hayashi, T. Kajitani

JOURNAL OF ELECTRONIC MATERIALS　39　(9)　1798-1802　2010/09

DOI： 10.1007/s11664-010-1135-2 　

ISSN： 0361-5235

eISSN： 1543-186X
Rubbing effect on surface morphology and thermoelectric properties of TTF-TCNQ thin films Peer-reviewed

E. Tamayo, K. Hayashi, T. Shinano, Y. Miyazaki, T. Kajitani

APPLIED SURFACE SCIENCE　256　(14)　4554-4558　2010/05

DOI： 10.1016/j.apsusc.2010.02.046 　

ISSN： 0169-4332
Spin dynamics of triangular lattice antiferromagnet CuFeO2: Crossover from spin-liquid to paramagnetic phase Peer-reviewed

K. Hayashi, T. Nozaki, R. Fukatsu, Y. Miyazaki, T. Kajitani

PHYSICAL REVIEW B　80　(14)　144413/1-144413/5　2009/10

DOI： 10.1103/PhysRevB.80.144413 　

ISSN： 1098-0121
Structure and High-Temperature Thermoelectric Properties of the n-Type Layered Oxide Ca2-x Bi (x-delta) MnO4-gamma Peer-reviewed

F. Kawashima, X. Y. Huang, K. Hayashi, Y. Miyazaki, T. Kajitani

JOURNAL OF ELECTRONIC MATERIALS　38　(7)　1159-1162　2009/07

DOI： 10.1007/s11664-009-0700-z 　

ISSN： 0361-5235

eISSN： 1543-186X
Electronic Structure and Thermoelectric Properties of the Delafossite-Type Oxides CuFe1-x Ni (x) O-2 Peer-reviewed

T. Nozaki, K. Hayashi, T. Kajitani

JOURNAL OF ELECTRONIC MATERIALS　38　(7)　1282-1286　2009/07

DOI： 10.1007/s11664-009-0775-6 　

ISSN： 0361-5235
Modulated crystal structure of chimney-ladder higher manganese silicides MnSi gamma (gamma similar to 1.74) Peer-reviewed

Yuzuru Miyazaki, Dai Igarashi, Kei Hayashi, Tsuyoshi Kajitani, Kunio Yubuta

PHYSICAL REVIEW B　78　(21)　214104-1-214104-8　2008/12

DOI： 10.1103/PhysRevB.78.214104 　

ISSN： 1098-0121
ronbun

arafune ryuichi, hayashi kei, takagi noriaki, kawai maki, uehara yoichi, ushioda sukekatsu

Abstract of annual meeting of the Surface Science of Japan　28　108-108　2008
Publisher: The Japan Society of Vacuum and Surface Science
DOI： 10.14886/sssj2008.28.0.108.0 　
High temperature thermoelectric properties of delafossite-type oxides CuFe0.98M0.02O2 (M=Mg, Zn, Ni, Co, Mn, or Ti) Peer-reviewed

T. Nozaki, K. Hayashi, T. Kajitani

PROCEEDINGS ICT 07: TWENTY-SIXTH INTERNATIONAL CONFERENCE ON THERMOELECTRICS　168-171　2008

ISSN： 1094-2734
Effect of doping on thermoelectric properties of delafossite-type oxide CuCrO2 Peer-reviewed

Kei Hayashi, Ken-ichi Sato, Tomohiro Nozaki, Tsuyoshi Kajitani

JAPANESE JOURNAL OF APPLIED PHYSICS　47　(1)　59-63　2008/01

DOI： 10.1143/JJAP.47.59 　

ISSN： 0021-4922
Structure and high temperature thermoelectric properties of delafossite-type oxide CuFe1-xNixO2 (0 <= x <= 0.05) Peer-reviewed

Kei Hayashi, Tomohiro Nozaki, Tsuyoshi Kajitani

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS　46　(8A)　5226-5229　2007/08

DOI： 10.1143/JJAP.46.5226 　

ISSN： 0021-4922
Spectroscopic evidence for energy loss of photoelectrons interacting with image charge Peer-reviewed

Ryuichi Arafune, Kei Hayashi, Shigenori Ueda, Yoichi Uehara, Sukekatsu Ushioda

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN　76　(4)　044604-1-044604-5　2007/04

DOI： 10.1143/JPSJ.76.044604 　

ISSN： 0031-9015
Fabrication and in-plane electrical resistivity of Ge/SiGe quantum dot superlattices Peer-reviewed

K. Hayashi, S. Abiko, N. Motegi, T. Kajitani

MICROPROCESSES AND NANOTECHNOLOGY 2007, DIGEST OF PAPERS　160-161　2007
Structural and Magnetic Transition Temperatures of Full Heusler Ni-Mn-Sn Alloys Determined by Van der Pauw Method Peer-reviewed

Tomoya Takenaga, Kei Hayashi, Tsuyoshi Kajitani

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN　40　(13)　1328-1329　2007

DOI： 10.1252/jcej.07WE154 　

ISSN： 0021-9592
Thermoelectric Properties of Delafossite-Type Oxide CuFe1-xNixO2 (0 <= x <= 0.05) Peer-reviewed

Tomohiro Nozaki, Kei Hayashi, Tsuyoshi Kajitani

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN　40　(13)　1205-1209　2007

DOI： 10.1252/jcej.07WE146 　

ISSN： 0021-9592
Derivative spectra of very low energy photoelectrons from CO/Cu(001) surface obtained by a lock-in technique Peer-reviewed

Kei Hayashi, Ryuichi Arafune, Shigenori Ueda, Yoichi Uehara, Sukekatsu Ushioda

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN　75　(10)　104303-1-104303-4　2006/10

DOI： 10.1143/JPSJ.75.104303 　

ISSN： 0031-9015
Detection of the frustrated rotation mode of CO on Cu(0 0 1) by very low energy photoelectron spectroscopy Peer-reviewed

R. Arafune, K. Hayashi, S. Ueda, Y. Uehara, S. Ushioda

Surface Science　600　(18)　3536-3539　2006/09/15

DOI： 10.1016/j.susc.2006.01.058 　

ISSN： 0039-6028
Laser photoelectron spectra of oxygen covered Cu(001) surface

ARAFUNE Ryuichi, HAYASHI Kei, TAKAGI Noriaki, KAWAI Maki, UEHARA Yoichi, USHIODA Sukekatsu

Abstract of annual meeting of the Surface Science of Japan　26　11-11　2006
Publisher: The Surface Science Society of Japan
DOI： 10.14886/sssj.26.0.11.0 　
Dynamics of very low energy photoelectrons interacting with image charge of Cs Cu(111) surface Peer-reviewed

K. Hayashi, R. Arafune, S. Ueda, Y. Uehara, S. Ushioda

Physical Review B - Condensed Matter and Materials Physics　72　(19)　2005/11/15

DOI： 10.1103/PhysRevB.72.195425 　

ISSN： 1098-0121 1550-235X
Inelastic photoemission due to scattering by surface adsorbate vibrations Peer-reviewed

R Arafune, K Hayashi, S Ueda, Y Uehara, S Ushioda

PHYSICAL REVIEW LETTERS　95　(20)　207601-1-207601-4　2005/11

DOI： 10.1103/PhysRevLett.95.207601 　

ISSN： 0031-9007

eISSN： 1079-7114
Dynamics of very low energy photoelectrons interacting with image charge of Cs/Cu(111) surface Peer-reviewed

K Hayashi, R Arafune, S Ueda, Y Uehara, S Ushioda

PHYSICAL REVIEW B　72　(19)　195425-1-195425-3　2005/11

DOI： 10.1103/PhysRevB.195425 　

ISSN： 2469-9950

eISSN： 2469-9969
Spike structure in the very low energy photoelectron spectra of Ag(001) Peer-reviewed

K Hayashi, R Arafune, S Ueda, S Ushioda

APPLIED SURFACE SCIENCE　237　(1-4)　296-300　2004/10

DOI： 10.1016/j.apsusc.2004.07.028 　

ISSN： 0169-4332
Magnetic dead layers induced by strain at fct Fe/Rh(001) interface Peer-reviewed

K Hayashi, M Sawada, H Yamagami, A Kimura, A Kakizaki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN　73　(9)　2550-2553　2004/09

DOI： 10.1143/JPSJ.73.2550 　

ISSN： 0031-9015
Magnetic dead layers in Fe films induced by a lattice mismatch at an interface Peer-reviewed

K Hayashi, M Sawada, H Yamagami, A Kimura, A Kakizaki

PHYSICA B-CONDENSED MATTER　351　(3-4)　324-327　2004/09

DOI： 10.1016/j.physb.2004.06.043 　

ISSN： 0921-4526
Energy loss of photoelectrons by interaction with image charge Peer-reviewed

R Arafune, K Hayashi, S Ueda, S Ushioda

PHYSICAL REVIEW LETTERS　92　(24)　247601-1-247601-4　2004/06

DOI： 10.1103/PhysRevLett.92.247601 　

ISSN： 0031-9007

eISSN： 1079-7114
Perpendicular magnetic anisotropy of Co/Pd(111) studied by spin-resolved photoelectron spectroscopy Peer-reviewed

M Sawada, K Hayashi, A Kakizaki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN　72　(5)　1161-1165　2003/05

DOI： 10.1143/JPSJ.72.1161 　

ISSN： 0031-9015
Spin-resolved photoemission and electronic structures of magnetic thin films - Perpendicular magnetic anisotropy of Co films Peer-reviewed

A Kakizaki, A Sawada, K Hayashi

JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA　124　(2-3)　281-288　2002/07

DOI： 10.1016/S0368-2048(02)00059-2 　

ISSN： 0368-2048
Electronic structures and reorientation of perpendicular magnetic anisotropy of Co/Au(111) and Co/Pd(111) Peer-reviewed

M Sawada, K Hayashi, A Kakizaki

SURFACE REVIEW AND LETTERS　9　(2)　865-869　2002/04

DOI： 10.1142/S0218625X0200307X 　

ISSN： 0218-625X
Structure and magnetism of Fe thin films grown on Rh(001) studied by photoelectron spectroscopy Peer-reviewed

K Hayashi, M Sawada, A Harasawa, A Kimura, A Kakizaki

PHYSICAL REVIEW B　64　(5)　2001/08

ISSN： 1098-0121

eISSN： 1550-235X
Electronic structure and magnetic anisotropy of Co/Au(111): A spin-resolved photoelectron spectroscopy study Peer-reviewed

M Sawada, K Hayashi, A Kakizaki

PHYSICAL REVIEW B　63　(19)　2001/05

ISSN： 1098-0121

eISSN： 1550-235X
Electronic structures of magnetic ultrathin films Co/Au(111) studied by spin-resolved photoelectron spectroscopy Peer-reviewed

M Sawada, K Hayashi, A Kakizaki

APPLIED SURFACE SCIENCE　169　176-179　2001/01

DOI： 10.1016/S0169-4332(00)00726-1 　

ISSN： 0169-4332
Electronic structure and magnetic anisotropy of Co/Au(111): a spin-resolved photoelectron spectroscopy study Peer-reviewed

M Sawada, K Hayashi, A Kakizaki

SPIN 2000　570　1006-1008　2001

ISSN： 0094-243X
Growth of Fe films on Rh(001): a photoemission study Peer-reviewed

K Hayashi, M Sawada, A Harasawa, A Kimura, A Kakizaki

APPLIED SURFACE SCIENCE　169　375-379　2001/01

DOI： 10.1016/S0169-4332(00)00687-5 　

ISSN： 0169-4332
Structure and magnetism of Fe thin films grown on Rh(001) studied by spin-resolved photoelectron spectroscopy Peer-reviewed

K Hayashi, M Sawada, A Harasawa, A Kimura, A Kakizaki

SPIN 2000　570　1003-1005　2001

ISSN： 0094-243X
Magnetic properties of fcc Fe thin films Peer-reviewed

A Kakizaki, N Kamakurra, M Sawada, K Hayashi, T Saitoh

SURFACE REVIEW AND LETTERS　7　(5-6)　667-671　2000/10

DOI： 10.1016/S0218-625X(00)00064-6 　

ISSN： 0218-625X

eISSN： 1793-6667
Spin-resolved photoelectron diffraction of Ag 4p electron on Fe/Ag(001) surface

Okuda T, Kinoshita T, Harasawa A, Sawada M, Hayashi K

Meeting abstracts of the Physical Society of Japan　55　(1)　643-643　2000/03/10
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Electronic states of fcc Fe/Co(001) of 5-11 monolayers probed by spin-resolved photoemission spectroscopy Peer-reviewed

N Kamakura, A Kimura, K Hayashi, A Harasawa, A Kakizaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS　38　415-418　1999

ISSN： 0021-4922

Show all ︎Show first 5

Misc. 37

格子欠陥を導入した高性能のp型Mg2Sn単結晶熱電材料を開発 Invited

林慶

日本熱電学会誌　21　(3)　158-159　2025/04
Development of Single Crystals with High Thermoelectric Performance by Introducing Lattice Defects Invited

Kei Hayashi

Journal of the Japanese Association for Crystal Growth　50　(3)　50-3-02　2023/10/31

DOI： 10.19009/jjacg.50-3-02 　
熱電発電の実用化に向けた格子欠陥含有単結晶の開発 Invited

林慶

アグリバイオ　7　39-41　2023/02/02
Publisher: 北隆館
Enhancement of thermoelectric performance of Mg2Sn single crystals via lattice-defect engineering International-journal Invited

JSAP Review　2022　220403　2022/07/29

DOI： 10.11470/jsaprev.220403 　

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Thermoelectric (TE) power generation, a potential clean power technology, has attracted significant attention owing to the recent development of high-performance TE materials. We focused on Mg2Sn and aimed to improve its TE performance by preparing single crystals (SCs) and introducing lattice defects. In this paper, experimental results on crystal structure analysis, microstructures, and TE properties are presented. It is demonstrated that the TE performance of Mg2Sn SCs can be superior to that of Mg2Sn polycrystals via lattice-defect engineering.
Enhancement of thermoelectric properties of Mg2Sn single crystals via lattice-defect engineering Invited Peer-reviewed

Kei Hayashi

Oyo Buturi　91　(5)　271-275　2022/05/10

DOI： 10.11470/oubutsu.91.5_271 　
Mg2Sn単結晶の点欠陥・線欠陥に対する化学的圧力の効果 Invited

林慶

日本熱電学会誌　18　(3)　145-146　2022/04/27
空孔欠陥を利用した単結晶熱電材料の開発 Invited

林慶

クリーンエネルギー　30　(6)　15-20　2021/06/05

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排熱から電気エネルギーを回収できる熱電発電の実現に向けて、高性能の熱電材料の開発が進められている。本稿では、材料価格が低く、価格性能比が高いマグネシウム錫化合物において、単結晶化・空孔欠陥の導入・電子キャリアの増加といった手法を駆使して高性能化を達成した研究成果を簡単に紹介する。
Thermoelectric properties of Mg2Si and its derivatives: effects of lattice defects and secondary phases Invited

K. Hayashi, Y. Miyazaki, W. Saito, M. Kubouchi, Y. Ogawa, S. Suzuki, Y. Hayashibara, I. Ando

Thermoelectric Materials -Principles and Concepts for Enhanced Properties-　99-116　2020/06/08
Publisher: De Gruyter
DOI： 10.1515/9783110596526 　
マグネシウムケイ化物の結晶構造と熱電性能 Invited

林慶, 窪内将隆

Materia Japan　56　(9)　546-553　2017/09/01
Publisher: 日本金属学会
DOI： 10.2320/materia.56.546 　

ISSN： 1340-2625
金属シリサイド系熱電材料研究の現状と展望 (小特集熱電変換材料の実用化へ向けた新規展望)

林慶, 宮﨑讓

金属　87　(2)　112-118　2017/02
Publisher: アグネ技術センター
ISSN： 0368-6337
金属シリサイド系熱電材料研究の現状と展望 Invited

林慶, 宮﨑讓

金属　87　(2)　20-26　2017/02/01
Publisher: アグネ技術センター
Thermoelectric energy conversion and ceramic thermoelectrics

T. Kajitani, Y. Miyazaki, K. Hayashi, K. Yubuta, X. Y. Huang, W. Koshibae

Materials Science Forum　671　1-20　2011/01/20

DOI： 10.4028/www.scientific.net/MSF.671.1 　

ISSN： 0255-5476
ラビング基板上に成膜したTTF-TCNQ薄膜の膜構造と熱電特性 Invited

林慶

日本熱電学会誌　6　(2)　9-12　2009/11/30
21pWH-6 An energy gain process in inelastic photoesmission through excitation of surface vibrations

Arafune R., Hayashi K., Takagi N., Kawai M., Uehara Y., Ushioda S.

Meeting abstracts of the Physical Society of Japan　62　(1)　928-928　2007/02/28
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
レーザー光電子スペクトル中に現れる振動励起非弾性構造 Invited

荒船竜一, 林慶, 高木紀明, 川合眞紀, 上原洋一, 潮田資勝

表面科学　28　(7)　378-384　2007
Publisher: The Surface Science Society of Japan
DOI： 10.1380/jsssj.28.378 　

ISSN： 0388-5321

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We have succeeded in observing vibrationally induced inelastic structures in the photoemission spectra of carbon monoxide or oxygen covered Cu(001) surfaces excited by laser light. The structure appears as a step at the vibrational energy below the Fermi level. We found that the CO/Cu(001) spectra contain two step structures arising from the C-O internal stretching mode and the frustrated rotation mode. These steps shift to lower energy for ¹³C¹⁸O. In the O/Cu(001) spectra we have observed the inelastic structures originating from not only adsorbate-substrate vibrations but also substrate surface phonons.
23pYC-1 Inelastic photoemission from the O/Cu(001) surface

Arafune R., Hayashi K., Takagi N., Kawai M., Uehara Y., Ushioda S.

Meeting abstracts of the Physical Society of Japan　61　(2)　724-724　2006/08/18
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
24pXD-3 The structure, the electronic state and the magnetism of Fe/Pd(001)

Seno Tetsuya, Morimoto Osamu, Hayashi Kei, Yu Dehong, Kakizaki Akito

Meeting abstracts of the Physical Society of Japan　60　(1)　851-851　2005/03/04
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Very Low Energy Photoelectron Spectroscopy: Energy Loss of Photoelectrons Invited

Kei Hayashi

Hyomen Kagaku　26　741-745　2005

DOI： 10.1380/JSSSJ.26.741 　
14aXD-7 The electric state and the structure of Fe/Pd(001)

Seno Tetsuya, Morimoto Osamu, Hayashi Kei, Kakizaki Akito

Meeting abstracts of the Physical Society of Japan　59　(2)　400-400　2004/08/25
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
14aXD-7 The electric state and the structure of Fe/Pd(001)

Seno Tetsuya, Morimoto Osamu, Hayashi Kei, Kakizaki Akito

Meeting abstracts of the Physical Society of Japan　59　(2)　811-811　2004/08/25
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
30aYE-10 Low energy photoelectron spectroscopy of Cs adsorbed surfaces of single crystals

Hayashi K., Arafune R., Ueda S., Ushioda S.

Meeting abstracts of the Physical Society of Japan　59　(1)　933-933　2004/03/03
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Low energy photoelectron spectroscopy of Cu single crystal surfaces

Arafune R., Hayashi K., Ushioda S.

Meeting abstracts of the Physical Society of Japan　58　(1)　842-842　2003/03/06
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Structure and Magnetism of Fe thin films grown on Pd(001) and Rh(001) surfaces

Hayashi K., Okuda T., Kinoshita T., Kakizaki A.

Meeting abstracts of the Physical Society of Japan　56　(2)　575-575　2001/09/03
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Temperature dependence of spin-resolved electronic states of Fe/Rh(001) (II)

Hayashi K., Harasawa A., Kinoshita T., Kakizaki A.

Meeting abstracts of the Physical Society of Japan　56　(2)　351-351　2001/09/03
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Temperature dependence of spin-polarized electronic states of Fe/Rh (001)

Hayashi K., Sawada M., Harasawa A., Morimoto O., Kakizaki A.

Meeting abstracts of the Physical Society of Japan　55　(2)　327-327　2000/09/10
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Electronic structures of PMA films of Co/Au(111)

Sawada M., Hayashi K., Kakizaki A.

Meeting abstracts of the Physical Society of Japan　55　(2)　328-328　2000/09/10
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
24aS-8 A relation between a magnetic anisotropy and a electron structure of Co/Au(111)

Sawada M, Hayashi K, Kamakura N, Harasawa A, Kakizaki A

Meeting abstracts of the Physical Society of Japan　54　(2)　335-335　1999/09/03
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
26pR-7 Structure and electronic states of Fe/Rh(001)

Hayashi Kei, Sawada Masahiro, Harasawa Ayumi, Kimura Akio, Kakizaki Akito

Meeting abstracts of the Physical Society of Japan　54　(2)　400-400　1999/09/03
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
28a-ZH-1 Spin-and angle-resolved photoemission study of Co/Au(111)

Sawada M., Kimura A., Hayashi K., Kamakura N., Harasawa A., Kakizaki A.

Meeting abstracts of the Physical Society of Japan　54　(1)　182-182　1999/03/15
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
28a-ZH-2 Spin dependent electronic states of fcc Fe/Co(001)

Kamakura N., Hayashi K., Kimura A., Harasawa A., Kakizaki A.

Meeting abstracts of the Physical Society of Japan　54　(1)　182-182　1999/03/15
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Angle-resolved photoemission spectroscopy study of Fe/Rh(100)

HAYASHI K., SAWADA M., KIMURA A., KAMAKURA N., HARASAWA A., KAKIZAKI A.

Meeting abstracts of the Physical Society of Japan　53　(2)　209-209　1998/09/05
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Spin resolved 3s photoemission of fct Fe/Co(001)

KAMAKURA N., HAYASHI K., KIMURA A., HARASAWA A., KAKIZAKI A.

Meeting abstracts of the Physical Society of Japan　53　(2)　209-209　1998/09/05
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Magnetic llnear dichroism in 3p core level photoemission of Fe/Co(001)

KAMAKURA N., HAYASHI K., KIMURA A., HARASAWA A., KAKIZAKI A.

Meeting abstracts of the Physical Society of Japan　53　(2)　209-209　1998/09/05
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Growth mode and electronic structure of Fe/Rh(001) and Fe/Co(001)

HAYASHI K., SAWADA M., KIMURA A., KAMAKURA N., HARASAWA A., KAKIZAKI A.

Meeting abstracts of the Physical Society of Japan　53　(2)　493-493　1998/09/05
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Spin dependent electronic structure in fct Fe/Co(001) II

KAMAKURA N., HAYASHI K., KIMURA A., HARASAWA A., KAKIZAKI A.

Meeting abstracts of the Physical Society of Japan　53　(2)　494-494　1998/09/05
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Interface electronic structure of Fe/Co(001)

KIMURA Akio, KAMAKURA Nozomu, HAYASHI Kei, HARASAWA Ayumi, KAKIZAKI Akito

Meeting abstracts of the Physical Society of Japan　53　(2)　494-494　1998/09/05
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Fe(001)spin dependent surface state

SAWADA M., KIMURA A., HAYASHI K., OHDATE S., KAMAKURA N., HARASAWA A., KAKIZAKI A.

Meeting abstracts of the Physical Society of Japan　53　(1)　423-423　1998/03/10
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349

Show all ︎Show first 5

Books and Other Publications 3

環境発電ハンドブック : 機能性材料・デバイス・標準化 : IoT時代で加速する社会実装

林慶, 齋藤亘, 中沢駿仁, 髙松智寿, 宮﨑讓

エヌ・ティー・エス　2021/10/29

ISBN: 9784860437480
Magnetic Materials and Magnetic Levitation

Kei Hayashi, Hezhang Li, Mao Eguchi, Yoshimi Nagashima, Yuzuru Miyazaki

IntechOpen　2020/06/30

DOI： 10.5772/intechopen.92867 　
Thermoelectric Materials -Principles and Concepts for Enhanced Properties-

Kei Hayashi, Yuzuru Miyazaki, Wataru Saito, Masataka Kubouchi, Yohei Ogawa, Shogo Suzuki, Yuta Hayashibara, Ikumi Ando

De Gruyter　2020/06/08

DOI： 10.1515/9783110596526

Presentations 181

High thermoelectric properties of Mg2Sn and Mg2Ge single crystals with engineered lattice defects International-presentation Invited

Kei Hayashi

Asia-Pacific Conference on Semiconducting Silicides and Related Materials 2025 (APAC Silicide 2025)　2025/07/19
Design of Oxide Thermoelectric Uni-leg Modules International-presentation

Yoshimi Shimizu, Kei Hayashi, Yuzuru Miyazaki

41st International Conference on Thermoelectrics & 7th Asian Conference on Thermoelectrics (ICT/ACT2025)
Formation of magnesium monovacancies by Sb doping into Mg2Sn crystals International-presentation

Mamoru Kitaura, Takuma Sumi, Yoshitaka Taira, Shinta Watanabe, Zhicheng Huang, Kei Hayashi, Yuzuru Miyazaki, Koji Michishio, Manabu Ishizaki, Akimasa Ohnishi

41st International Conference on Thermoelectrics & 7th Asian Conference on Thermoelectrics (ICT/ACT2025)
Characterization of thermoelectric single leg using high-performance Mg2Sn-based single crystal International-presentation

Shin Sato, Kei Hayashi, Zhicheng Huang, Yuzuru Miyazaki

41st International Conference on Thermoelectrics & 7th Asian Conference on Thermoelectrics (ICT/ACT2025)
Preparation and Thermoelectric Properties of Partially-substituted Chimney-ladder Compounds (Fe1-xCox)Geγ (γ~1.52) International-presentation

Tatsuhiro Kurosawa, Zhicheng Huang, Kei Hayashi, Yuzuru Miyazaki

41st International Conference on Thermoelectrics & 7th Asian Conference on Thermoelectrics (ICT/ACT2025)
Preparation and Thermoelectric Properties of Doubly-substituted Fe-based Half-Heusler Alloys (V1-xTix)(Fe1-yCoy)Sb International-presentation

Hiroaki Konishi, Xue Nan, Zhicheng Huang, Kei Hayashi, Yuzuru Miyazaki

41st International Conference on Thermoelectrics & 7th Asian Conference on Thermoelectrics (ICT/ACT2025)
Chemical bond engineering towards optimal-performance V1-xTixCo1-yFeySb half-Heusler thermoelectrics International-presentation

Xue Nan, Kei Hayashi, Hiroaki Konishi, Zhicheng Huang, Yuzuru Miyazaki

41st International Conference on Thermoelectrics & 7th Asian Conference on Thermoelectrics (ICT/ACT2025)
Data-driven approach for potential iron-based half-Heusler thermoelectrics with chemical bonding characteristics International-presentation

Xue Nan, Kei Hayashi, Zhicheng Huang, Yuzuru Miyazaki

41st International Conference on Thermoelectrics & 7th Asian Conference on Thermoelectrics (ICT/ACT2025)
Enhancement of Thermoelectric Properties in P-Type V0.6Ti0.4FeSb Alloys via Point Defects Engineering International-presentation

Zhicheng Huang, Xue Nan, Hiroaki Konishi, Kei Hayashi, Yuzuru Miyazaki

41st International Conference on Thermoelectrics & 7th Asian Conference on Thermoelectrics (ICT/ACT2025)　2025/06/18
Graphene-Assisted Electronic DOS Modulation and Phonon Scattering to Improve the Thermoelectric Performance of Mg3Sb2-Based Materials International-presentation International-coauthorship

Qiang Zhang, Jiadang Li, Nagendra S. Chauhan, Zhicheng Huang, Wenhao Fan, Kei Hayashi, Shaoping Chen, Yuzuru Miyazaki

41st International Conference on Thermoelectrics & 7th Asian Conference on Thermoelectrics (ICT/ACT2025)
Thermoelectric enhancement in half-metallic full-Heusler Mn2VAl alloy through control of nonstoichiometry International-presentation International-coauthorship

Kei Hayashi, Gakuto Kanno, Hezhang Li, Zhicheng Huang, Jing-Feng Li, Yuzuru Miyazaki

41st International Conference on Thermoelectrics & 7th Asian Conference on Thermoelectrics (ICT/ACT2025)　2025/06/18
Preparation of Mg2Sn and Mg2Ge Single Crystals for Thermoelectric Application Invited

Kei Hayashi

Taiwan Consortium of Emergent Crystalline Materials (TCECM)　2025/05
Development of single crystalline Mg2Sn and Mg2Ge thermoelectrics with engineered lattice defects International-presentation Invited

Kei Hayashi

2025 Taiwan-Japan Workshop on Crystal Growth, Analysis and Calculation (TJ-CGAC)　2025/05
Data-driven approach to find potential Fe-based half-Heusler thermoelectric materials for the near-room-temperature applications

Yuzuru Miyazaki, Xue Nan, Zhicheng Huang, Kei Hayashi

16th International Conference on Materials and Manufacturing Technologies (ICMMT 2025)
電子・陽電子プローブを用いた熱電半導体Mg2Sn中のアンチモンとマグネシウム空孔の局所構造解析

隅琢磨, 北浦守, 橋本由介, 山本裕太, 松下智裕, 平義隆, 渡邊真太, 黄志成, 林慶, 宮﨑讓, 満汐孝治, 石崎学, 大西彰正

日本物理学会 2025年春季大会　2025/03/19
Preparation and thermoelectric properties of nonstoichiometric Mn2VAl

2025/03/09
光電子ホログラフィーとガンマ線誘起陽電子消滅寿命分光によって調べたMg2Sn結晶のアンチモン添加効果IV

隅琢磨, 北浦守, 橋本由介, 山本裕太, 松下智裕, 平義隆, 渡邊真太, 黄志成, 林慶, 宮﨑讓, 満汐孝治, 石崎学, 大西彰正

超秩序構造科学第9回報告会　2025/03/08
Effect of Sb Doping on Mg2Sn Crystals Studied by Gamma-induced-Positron Annihilation Lifetime Spectroscopy and Photoelectron Holography Experiments

Takuma Sumi, Mamoru Kitaura, Yusuke Hashimoto, Yuta Yamamoto, Tomohiro Matsushita, Yoshitaka Taira, Shinta Watanabe, Zhicheng Huang, Kei Hayashi, Yuzuru Miyazaki, Manabu Ishizaki, Akimasa Ohnishi

Symposium on Hyper-Ordered Structure Sciences in London　2025/01/29
(Mn,Ru,V)Siγ多結晶の単相試料の合成と熱電性能

千葉俊明, 林慶, 大山達也, 加藤尚, 宮﨑讓

第79回応用物理学会東北支部学術講演会　2024/12/06
非化学量論組成Mn2VAlの作製と熱電特性

菅野楽人, 林慶, 黄志成, 宮﨑讓

第79回応用物理学会東北支部学術講演会　2024/12/06
チムニーラダー型化合物 (Fe1-xCox)Geγ (γ~1.52) の合成と熱電特性

黒沢立浩, 黄志成, 林慶, 宮﨑讓

第79回応用物理学会東北支部学術講演会　2024/12/06
Data-driven approach for potential half-Heusler thermoelectrics with chemical bonding characteristics

Xue Nan, Zhicheng Huang, Kei Hayashi, Yuzuru Miyazaki

2024/12/06
MgCu2O3の合成と電気化学特性

上原和真, 周子涵, 黄志成, 林慶, 宮﨑讓

第79回応用物理学会東北支部学術講演会　2024/12/06
Mg2Sn熱電単結晶の単素子の作製と発電特性

佐藤心, 林慶, 黄志成, 宮﨑讓

第79回応用物理学会東北支部学術講演会　2024/12/06
高圧下で作製したMg2Sn単結晶の熱電性能

村山一希, 林慶, 黄志成, 宮﨑讓

第79回応用物理学会東北支部学術講演会　2024/12/06
Decreasing the carrier concentration of CrSi2 via Si adjustment and Mn substitution International-presentation

Bing Lan, Kei Hayashi, Zhicheng Huang, Toshiaki Chiba, Yuzuru Miyazaki

35th International Photovoltaic Science and Engineering Conference (PVSEC-35)　2024/11/12
Preparation of (Mn,Fe,V)Siγ Single Crystals for Infrared Absorption Optoelectronics International-presentation

Toshiaki Chiba, Kei Hayashi, Makoto Shimizu, Yuzuru Miyazaki

35th International Photovoltaic Science and Engineering Conference (PVSEC-35)　2024/11/12
Defect engineering to enhance thermoelectric performance of Mg2Sn and Mg2Ge single crystals International-presentation Invited

Kei Hayashi

New Zealand–Japan Workshop on Emerging Solid-State Technology for Low-Enthalpy Energy Harvesting　2024/11/12
Effect of Sb Doping on Mg2Sn Crystals Studied by Gamma-induced-Positron Annihilation Lifetime Spectroscopy and Photoelectron Holography Experiments

Takuma Sumi, Mamoru Kitaura, Yusuke Hashimoto, Yuta Yamamoto, Tomohiro Matsushita, Yoshitaka Taira, Shinta Watanabe, Zhicheng Huang, Kei Hayashi, Yuzuru Miyazaki, Manabu Ishizaki, Akimasa Ohnishi

2024/11/05
Effect of Sb Doping on Mg2Sn Crystals Studied by Gamma-induced-Positron Annihilation Lifetime Spectroscopy and Photoelectron Holography Experiments International-presentation

Takuma Sumi, Mamoru Kitaura, Yusuke Hashimoto, Yuta Yamamoto, Tomohiro Matsushita, Yoshitaka Taira, Shinta Watanabe, Zhicheng Huang, Kei Hayashi, Yuzuru Miyazaki, Manabu Ishizaki, Akimasa Ohnishi

The 13th International Workshop on Positron and Positronium Chemistry (PPC13)　2024/10/29
Preparation, Crystal Structure and Electrochemical Properties of Mg1-XCu2+XO3 International-presentation

K Uehara, Z Zihan, Z Huang, K Hayashi, Y Miyazaki

PRiME 2024
光電子ホログラフィーとガンマ線誘起陽電子消滅寿命分光によって調べたMg2Sn結晶のアンチモン添加効果III

隅琢磨, 北浦守, 橋本由介, 山本裕太, 松下智裕, 平義隆, 渡邊真太, 黄志成, 林慶, 宮﨑讓, 石崎学, 大西彰正

超秩序構造科学第8回成果報告会　2024/09/24
酸化物熱電材料を用いたUni-leg熱電発電モジュールの設計

清水嘉, 林慶, 宮﨑譲

第21回日本熱電学会学術講演会　2024/09/25
First-Principles Study for High Thermoelectric Performance Iron-based Half-Heusler Compounds with Thermodynamic and Mechanical Stability

Xue Nan, Zhicheng Huang, Kei Hayashi, Hiroaki Konishi, Yuzuru Miyazaki

第21回日本熱電学会学術講演会　2024/09/25
チムニーラダー型化合物(Fe1−xCox)Geγ (γ~1.52)の合成と熱電特性

黒沢立浩, 黄志成, 林慶, 宮﨑讓

第21回日本熱電学会学術講演会　2024/09/24
格子欠陥を導入したMg2Ge単結晶のp型熱電性能 International-coauthorship

林慶, 黄志成, 竹内裕人, 李敬鋒, 宮﨑讓

第21回日本熱電学会学術講演会　2024/09/24
Lattice defect engineering for high-performance Mg2Sn and Mg2Ge thermoelectric single crystals International-presentation Invited

Kei Hayashi, Zhicheng Huang, Hiroto Takeuchi, Yuzuru Miyazaki

14th International Conference on Ceramic Materials and Components for Energy and Environmental Systems (cmcee14)　2024/08/19
Enhancement of Thermoelectric Properties in p-type Iron-based Half-Heusler VFeSb Alloys via Titanium Alloying International-presentation

Zhicheng HUANG, Kei Hayashi, Xue Nan, Hiroaki Konishi, Yuzuru Miyazaki

The joint 40th International and 20th European Thermoelectric Conference (ICT/ECT 2024)　2024/07/03
Enhanced p-type thermoelectric properties of Mg2Ge single crystals via lattice defect engineering International-presentation International-coauthorship

Kei Hayashi, Hiroto Takeuchi, Zhicheng Huang, Nagendra S. Chauhan, Qiang Zhang, Xue Nan, Hezhang Li, Jun Pei, Jinfeng Dong, Bo-Ping Zhang, Jing-Feng Li, Yuzuru Miyazaki

The joint 40th International and 20th European Thermoelectric Conference (ICT/ECT 2024)　2024/07/03
光電子ホログラフィーとガンマ線誘起陽電子消滅寿命分光によって調べたMg2Sn結晶のアンチモン添加効果II

隅琢磨, 北浦守, 橋本由介, 松下智裕, 平義隆, 渡邊真太, 黄志成, 林慶, 宮﨑讓, 石崎学, 大西彰正

超秩序構造科学第4回若手の学校　2024/04/27
光電子ホログラフィーとガンマ線誘起陽電子消滅寿命分光によって調べたMg2Sn結晶におけるアンチモン添加効果

隅琢磨, 北浦守, 橋本由介, 松下智裕, 平義隆, 渡邊真太, 黄志成, 林慶, 宮﨑讓, 石崎学, 大西彰正

超秩序構造科学第7回報告会　2024/03/04
Thermoelectric properties of Sr-substituted [Ca2(Co0.65Cu0.35)2O4]pCoO2 International-presentation

Yoshimi Shimizu, Kei Hayashi, Yuzuru Miyazaki

MRM2023/IUMRS-ICA2023　2023/12/15
近赤外光吸収材料(Mn,Fe,V)Siγ単結晶の作製

千葉俊明, 林慶, 宮﨑讓

2023年応用物理学会東北支部第78回学術講演会　2023/12/06
GiPALS実験によって調べたMg₂Sn結晶におけるアンチモン添加効果

隅琢磨, 北浦守, 平義隆, 渡邊真太, 黄志成, 林慶, 宮﨑讓, 石崎学, 大西彰正

UVSORシンポジウム2023　2023/12/02
白色中性子ホログラフィーによるLi, B共ドープMg2Sn熱電材料の研究

黒梅智子, 阿部幸樹, 滝田正勝, 小林洋大, 富松優花, 會澤幸希, 川上修汰, 原田正英, 及川健一, 稲村泰弘, 林慶, 黄志成, 宮﨑讓, 林好一, 大山研司

超秩序構造科学第6回報告会　2023/11/17
High Temperature X-ray Diffraction Study on Incommensurate Composite Crystal (Mn,Fe,V)Siγ International-presentation

T. Chiba, K. Hayashi, Y. Miyazaki

The 15th Pacific Rim Conference of Ceramic Societies (PACRIM15) & The 13th International Conference on High-Performance Ceramics (CICC-13)　2023/11/06
Enhancing Thermoelectric Properties of P-type Mg2Sn Single Crystals through Li/Si Co-Doping and Introduction of Lattice Defects International-presentation International-coauthorship

Zhicheng Huang, Kei Hayashi, Yuzuru Miyazaki

The 15th Pacific Rim Conference of Ceramic Societies (PACRIM15) & The 13th International Conference on High-Performance Ceramics (CICC-13)　2023/11/08
Lattice Defect Engineering to Develop Highly-Efficient Thermoelectric Single Crystals International-presentation International-coauthorship Invited

Kei Hayashi

The 15th Pacific Rim Conference of Ceramic Societies (PACRIM15) & The 13th International Conference on High-Performance Ceramics (CICC-13)　2023/11/07
Analysis of crystal structure and Thermoelectric properties of Sr‐substituted [Ca2CoO3]pCoO2 International-presentation

Y. Shimizu, K. Hayashi, Y. Miyazaki

19th European Conference on Thermoelectrics (ECT2023)　2023/09/20
Preparation and thermoelectric properties of nonstoichiometric full‐Heusler Mn2+xV1-xAl alloys International-presentation International-coauthorship

G. Kanno, K. Hayashi, Z. Huang, H. Li, Y. Miyazaki

19th European Conference on Thermoelectrics (ECT2023)
Single‐phase synthesis and thermoelectric properties of nowotony chimney‐ladder FeGeγ International-presentation

T. Kurosawa, K. Hayashi, Y. Miyazaki

19th European Conference on Thermoelectrics (ECT2023)
Study of Li, B co-doped Mg2Sn thermoelectric material by white neutron holography

The 23rd Annual Meeting of The Japanese Society for Neutron Science (JSNS2023)　2023/09/13
Boron doping in n-type and p-type Mg2Sn on the generation of lattice defects leading to improved thermoelectric properties

Z. Huang, K. Hayashi, W. Saito, H. Takeuchi, Y. Miyazaki

39th Annual International Conference on Thermoelectrics (ICT2023)　2023/06/22
Advancing the thermoelectric performance of single crystals: a case study of p-type Mg2Sn through lattice defect engineering International-presentation International-coauthorship

K. Hayashi, Z. Huang, W. Saito, J. Pei, J.F. Li, Y. Miyazaki

39th Annual International cinference on Thermoelectrics (ICT2023)　2023/06/23
[Ca2(Co0.65Cu0.35)2O4]0.63CoO2の配向バルク体の作製と熱電特性

清水嘉, 林慶, 宮﨑讓

第70回応用物理学会春季学術講演会　2023/03/16
Mn部分置換CrSi2の赤外線吸収効率化のためのアニール条件の検討 International-coauthorship

田﨑海地, 林慶, 髙松智寿, 李敬鋒, 宮﨑讓

第70回応用物理学会春季学術講演会　2023/03/16
Carrier density control of CrSi2 partially substituted with Mn International-presentation

K. Tasaki, K. Hayashi, Y. Miyazaki

33rd International Photovoltaic Science and Engineering Conference (PVSEC-33)　2022/11/15
Preparation of (Mn,Fe,V)Siγ Single Crystals for Infrared Absorption Optoelectronics International-presentation

T. Chiba, K. Hayashi, Y. Miyazaki

33rd International Photovoltaic Science and Engineering Conference (PVSEC-33)　2022/11/15
格子欠陥エンジニアリングによるMg2Si関連物質の熱電性能の向上 Invited

林慶

第39回シリサイド系半導体研究会　2022/09/24

More details Close

Mg2Si関連物質は高性能の熱電材料として注目されている。これまで、熱電性能を向上するために、元素部分置換した多結晶を作製することで、キャリア密度の最適化や格子熱伝導率の低減が行われてきた。これに対し、単結晶は多結晶より高いキャリア移動度を有する一方で、格子熱伝導率も高いことから、Mg2Si関連物質の単結晶の熱電性能を調査した研究は少ない。本発表では、物理的圧力や化学的圧力を加えて単結晶を作製すると格子欠陥が導入されること、これにより熱伝導率が低くなるものの、高いキャリア移動度は維持され、多結晶よりも高い性能が得られるという我々の最近の成果について報告する。
Optical properties of CrSi2 thin films prepared by pulsed laser deposition method International-coauthorship

Kaichi Tasaki, Kei Hayashi, Tomohisa Takamatsu, Jing-Feng Li, Yuzuru Miyazaki

2022/09/20
Si substitution effect on thermoelectric properties of Mn2VAl with optimized order degree International-coauthorship

2022/09/21
Point Defects and Thermoelectric Properties of Melt‐grown Mg2Ge Single Crystals International-presentation

H. Takeuchi, Z. Huang, K. Hayashi, Y. Miyazaki

18th European Conference on Thermoelectrics (ECT'22)　2022/09/14
Realising enhanced thermoelectric performance in partially substituted higher manganese silicides crystals International-presentation

N. S. Chauhan, I. Ono, K. Hayashi, Y. Miyazaki

18th European Conference on Thermoelectrics (ECT'22)　2022/09/16
Reduction of Thermal Conductivity of M2Sn Single Crystal via Lattice-Defect Engineering through Chemical-Pressure Control International-presentation

K. Hayashi, W. Saito, Z. Huang, K. Sugimoto, K. Ohoyama, N. Happo, M. Harada, K. Oikawa, Y. Inamura, K. Hayashi, T. Miyazaki, Y. Miyazaki

18th European Conference on Thermoelectrics (ECT'22)　2022/09/14
Fe, V共置換によるn型MnSiγ単結晶の作製と熱電性能 International-coauthorship

林慶, 千葉俊明, Nagendra Singh Chauhan, 李敬鋒, 宮﨑讓

第19回日本熱電学会学術講演会　2022/08/08
Effect of spark plasma sintering temperature on microstructures across the interfaces between thermoelectric-material Mg2Si and Ni electrode

I. Murakami, T. Ishii, H. Sugawara, H. Kawada, S. Kurosu, H. Shimizu, H. Sato, T. Hanajiri, I. Ando, K. Hayashi, Y. Miyazaki

The 6th Asia-Pacific Conference on Semiconducting Silicides and Related Materials (APAC-Silicide 2022)　2022/08/01
Partially compensated (Ru, V) co-doped higher manganese silicide single crystals

N. S. Chauhan, I. Ono, K. Hayashi, Y. Miyazaki

The 6th Asia-Pacific Conference on Semiconducting Silicides and Related Materials (APAC-Silicide 2022)　2022/07/30
Preparation and High-Temperature Thermoelectric Properties of Textured Cobaltate Ceramics International-presentation

Y. Shimizu, K. Hayashi, Y. Miyazaki

Virtual Conference on Thermoelectrics 2022 (VCT 2022)　2022/07/20
Feで部分置換したMnSiγ単結晶の作製と評価

千葉俊明, 林慶, 宮﨑讓

第69回応用物理学会春季学術講演会　2022/03/22
Crystal Structures and Thermoelectric Properties of Li-doped Mg2Sn Single Crystals

Z. Huang, K. Hayashi, Y. Miyazaki

第69回応用物理学会春季学術講演会　2022/03/24
Mg2Si単結晶のSi空孔陥形成に対する酸素の効果

林慶, 川村聡太, 橋本由介, 赤尾昇, 黄志成, 齋藤亘, 田﨑海地, 林好一, 松下智裕, 宮﨑讓

第69回応用物理学会春季学術講演会　2022/03/24
Crystal structure, microstructure and thermoelectric properties of melt-grown β-Zn4Sb3 International-presentation

K. Hayashi, S. Yoshioka, T. Chiba, Y. Miyazaki

Materials Research Meeting 2021 (MRM2021)　2021/12/15
近赤外光利用太陽電池のための(Mn1-xFex)Siγ単結晶の作製

千葉俊明, 林慶, 宮﨑讓

第76回応用物理学会東北支部学術講演会　2021/12/03
Mn部分置換によるCrSi2のキャリア密度制御

田﨑海地, 林慶, 宮﨑讓

第76回応用物理学会東北支部学術講演会　2021/12/03
溶融合成したMg2Ge単結晶のMg空孔欠陥と熱電性能

竹内裕人, 林慶, 黄志成, 宮﨑讓

第76回応用物理学会東北支部学術講演会　2021/12/03
Point defect engineering enhances thermoelectric performance of Mg2Si and Mg2Sn single crystals International-presentation Invited

Kei Hayashi

The 1st Japan-France Virtual Workshop on Thermoelectrics　2021/09/30
Effect of order degree on thermoelectric properties of Mn2VAl full-Heusler alloys

Kei Hayashi, Hezhang Li, Yuzuru Miyazaki

2021/09/15
Preparation and thermoelectric properties of crack-free melt-grown Zn4Sb3

Kei Hayashi, Shun Yoshioka, Toshiaki Chiba, Yuzuru Miyazaki

2021/09/10
N-type origin of half-Heusler V(Fe1-xCox)Sb compounds

Y. Huang, K. Hayashi, Y. Miyazaki

2021/08/24
Point defects and thermoelectric properties of B-doped Mg2Si single crystals

2021/08/23
Discharge Plasma Sintered Themoelectric Material Mg2Si/Ni Electrode Interface Observation and Evaluation

2021/08/21
The Crystal Structures and Thermoelectric Properties of Ag-doped Mg2Sn

Z. Huang, K. Hayashi, W. Saito, Y. Miyazaki

2021/03/17
SbとBの共置換によるMg2Sn単結晶の熱電性能の向上

齋籐亘, 林慶, 黄志成, 宮﨑讓

第68回応用物理学会春季学術講演会　2021/03/17
ホウ素で部分置換したMg2Sn単結晶の結晶構造と熱電特性

林慶, 齋藤亘, 黄志成, 杉本和哉, 山本隆文, 大山研司, 八方直久, 原田正英, 及川健一, 稲村康弘, 林好一, 宮﨑讓

第68回応用物理学会春季学術講演会　2021/03/17
Design and evaluation of the C40-type silicide thermoelectric modules

M. Ryu, T. Takamatsu, K. Hayashi, Y. Miyazaki

The 5th Asian Conference on Thermoelectrics (ACT5) &The 6th Southeast Asia Conference on Thermoelectrics (SACT6)　2020/12/17
Preparation, crystal structure and thermoelectric performance of p-type quaternary half-Heusler Ti(Fe0.5+xNi0.5-x)Sb compounds

Z. Liu, Y. Huang, K. Hayashi, Y. Miyazaki

The 5th Asian Conference on Thermoelectrics (ACT5) &The 6th Southeast Asia Conference on Thermoelectrics (SACT6)　2020/12/17
Influences of Mg vacancy and Ga atoms in p-type Mg2Sn1-xGax

Z. Huang, K. Hayashi, W. Saito, J. Dong, J.-F. Li, Y. Miyazaki

The 5th Asian Conference on Thermoelectrics (ACT5) &The 6th Southeast Asia Conference on Thermoelectrics (SACT6)　2020/12/17
Effect of disorder on electronic structure and thermoelectrical properties of inverse full-Heusler Mn2CoAl alloys

H. Li, K. Hayashi, Y. Nagashima, S. Yoshioka, J. Dong, J.-F. Li, Y. Miyazaki

The 5th Asian Conference on Thermoelectrics (ACT5) &The 6th Southeast Asia Conference on Thermoelectrics (SACT6)　2020/12/17
Local Structure and Thermoelectric Properties of Boron-Doped Mg2Si and Mg2Sn Single Crystals

K. Hayashi, W. Saito, K. Sugimoto, S. Uchi, Y. Kanazawa, Y. Fukumoto, T. Yamamoto, K. Ohoyama, K. Hayashi, N. Happo, M. Hatada, K. Oikawa, Y. Inamura, Y. Miyazaki

The 5th Asian Conference on Thermoelectrics (ACT5) &The 6th Southeast Asia Conference on Thermoelectrics (SACT6)　2020/12/17
Effects of V-substitution on Thermoelectric Properties of Pseudogap Intermetallic TiNiSi Compound

Y. Huang, H. Nagai, K. Hayashi, Y. Miyazaki

The 2nd International Conference on Metals and Alloys (CMA 2020)　2020/12/07
Relationship between order degree and thermoelectric properties of Heusler compounds

Kei Hayashi

Tohoku University - RIKEN Joint Symposium Online Poster session　2020/12/01
Preparation and Thermoelectric Properties of Mn₂CoAl Inverse Full-Heusler Alloy

H. Li,K. Hayashi,Y. Nagashima, Y. Miyazaki

The 2020 Magnetism and Magnetic Materials Virtual Conference (MMM2020) (online)　2020/11
自動車廃熱・産業廃熱を利用した大規模熱電発電のための大型単結晶熱電材料の開発

Kei Hayashi, Hiroshi Abe

2020/10/26
白色中性子ホログラフィーを用いた熱電材料Mg₂X (X=Si,Sn)の局所構造解析

杉本和哉, 山本隆文, 林好一, 八方直久, 原田正英, 及川健一, 稲村康弘, 林慶, 齋藤亘, 宮﨑讓, 大山研司

2020年日本物理学会秋季大会 (オンライン)　2020/09
Mg空孔欠陥の導入とSb置換によるMg₂Sn単結晶の熱電性能向上

齋籐亘, 林慶, 黄志成, 宮﨑讓

第81回応用物理学会秋季学術講演会 (オンライン)　2020/09
Enhanced Thermoelectric Performance in N-type Half-Heulser VFeSb Compounds with Cobalt-substitution

Y. Huang, K. Hayashi, Y. Miyazaki

Virtual Conference on Thermoelectrics (online)　2020/07
Enhancing Thermoelectric Performance of Mg₂Sn Single Crystals via Point Defect Engineering and Sb-doping

W. Saito, K. Hayashi, Y. Miyazaki

Virtual Conference on Thermoelectrics (online)　2020/07
Mg空孔欠陥の導入によるMg₂Si_2-xSb_x単結晶の熱電性能向上

2020/03
Determination of dopant position of thermoelectric material B-doped Mg2Si by white neutron holography

K. Sugimoto, S. Uechi, Y. Kanazawa, Y. Fukumoto, T. Yamamoto, K. Ohoyama, K. Hayashi, N. Happo, M. Harada, K. Oikawa, Y. Inamura, K. Hayashi, W. Saito, Y. Miyazaki

Material Research Meeting 2019 (MRM2019)　2019/12
Mn₂VAlフルホイスラー合金の熱電特性と規則度の関係

2019/12/02
マンガンケイ化物の元素置換による熱電特性に関する研究

張蘊財, 永井宏樹, 林慶, 宮﨑讓

第74回応用物理学会東北支部学術講演会　2019/12/02
Thermoelectric Properties of Melt-Grown Mg₂Sn_1–xGa_x Ingots

Z. Huang, W. Saito, K. Hayashi, Y. Miyazaki

2019/12/02
溶融合成したZn₄Sb₃におけるクラック生成機構

吉岡駿, 林慶, 宮﨑讓

第74回応用物理学会東北支部学術講演会　2019/12/02
スピンギャップレス半導体Mn₂CoAlの熱電性能

永島良美, 李和章, 林慶, 宮﨑讓

第74回応用物理学会東北支部学術講演会　2019/12/02
Thermoelectric Properties and Local Structure of Boron-Doped Mg₂Si and Mg₂Sn International-presentation

Kei Hayashi, Wataru Saito, Yuzuru Miyazaki, Kazuya Sugimoto, Syoichi Uechi, Yuki Kanazawa, Yohei Fukumoto, Takayoshi Yamamoto, Kenji Ohoyama, Koichi Hayashi, Naohisa Happo, Masahide Harada, Kenichi Oikawa, Yasuhiro Inamura

14th International Conference on the Structure of Non-Crystalline Materials (NCM14)　2019/11/05
Preparation, thermoelectric properties, and local structure of B-doped Mg₂Si single crystal International-presentation

Kei Hayashi, Wataru Saito, Yuzuru Miyazaki, Kazuya Sugimoto, Syoichi Uechi, Yuki Kanazawa, Yohei Fukumoto, Takayoshi Yamamoto, Kenji Ohoyama, Koichi Hayashi, Naohisa Happo, Masahide Harada, Kenichi Oikawa, Yasuhiro Inamura

Tsukuba Conference　2019/10/02
エネルギーハーベスティングが拓く未来 -身の周りのエネルギーから電気をつくる- Invited

林慶

東北大学-住友金属鉱山ビジョン共創型パートナーシップ第1回組織的連携ワークショップ　2019/10/01
Mg空孔欠陥を含むMg₂Sn単結晶の熱電性能と微細組織

齋籐亘, 林慶, 宮﨑讓

第80回応用物理学会秋季学術講演会　2019/09/19
C40型(Mn,Cr)(Si,Al)₂系化合物における熱電特性の組成および合成条件依存性

齋藤啓介, 髙松智寿, 林慶, 宮﨑讓

第16回日本熱電学会学術講演会　2019/09/03
ペロブスカイト型酸水素化物ATiO_3-xH_x (A = Ca, Sr)の合成と熱電特性

髙松智寿, 福留大輝, 林慶, 宮﨑讓

第16回日本熱電学会学術講演会　2019/09/03
Cross-sectional characterization of Mg₂Si-Ni interface compacted by SPS method at 800°C International-presentation

T. Ishii, H. Sugawara, M. Tokuda, H. Sato, T. Hanajiri, H. Shimoshige, S. Kurosu, K. Hayashi, I. Ando, W. Saito, Y. Miyazaki

5th Asia-Pacific conference on semiconducting silicides and related materials (APAC-SILICIDE 2019)　2019/07/22
Crystal structure evolution of Zn₄Sb₃ during melt grown process International-presentation

S. Yoshioka, K. Hayashi, Y. Miyazaki

38th International and 4th Asian Conference on Thermoelectrics (ICT & ACT 2019)　2019/07/02
Preparation, crystal structure and thermoelectric properties of Ru substituted half Heusler type VFeSb International-presentation

Y. Huang, K. Hayashi, Y. Miyazaki

38th International and 4th Asian Conference on Thermoelectrics (ICT & ACT 2019)　2019/07/02
Thermoelectric Properties of Strontium Titanium Oxyhydrides International-presentation

D. Fukutome, T. Takamatsu, K. Hayashi, Y. Miyazaki

38th International and 4th Asian Conference on Thermoelectrics (ICT & ACT 2019)　2019/07/02
Computer simulation of thermoelectric properties for tilted multilayer devices based on the off diagonal thermoelectric effect International-presentation

D. Sakuraba, N. Kodaira, K. Hayashi, Y. Miyazaki

38th International and 4th Asian Conference on Thermoelectrics (ICT & ACT 2019)　2019/07/02
Investigation on lattice defects in Mg₂Sn single crystals prepared under different Ar partial pressure International-presentation

W. Saito, K. Hayashi, Y. Miyazaki

38th International and 4th Asian Conference on Thermoelectrics (ICT & ACT 2019)　2019/07/02
Thermoelectric properties and local structure of B doped Mg₂Si single crystal International-presentation

K. Hayashi, W. Saito, Y. Miyazaki, K. Sugimoto, S. Uechi, Y. Kanazawa, Y. Fukumoto, T. Yamamoto, K. Ohyama, N. Happo, M. Harada, K. Oikawa, Y. Inamura

38th International and 4th Asian Conference on Thermoelectrics (ICT & ACT 2019)　2019/07/02
Crystal and electronic structures of the half Heusler type VFeSb compounds International-presentation

Y. Huang, S. Maki, K. Hayashi, Y. Miyazaki

38th International and 4th Asian Conference on Thermoelectrics (ICT & ACT 2019)　2019/07/01
Preparation and Thermoelectric Properties of Mn2VAl Full Heusler Alloys with Different Order Degree International-presentation

H. Li, K. Hayashi, Y. Miyazaki

38th International and 4th Asian Conference on Thermoelectrics (ICT & ACT 2019)　2019/07/01
Development of efficient thermoelectric materials－crystal structure, electronic structure, and morphology－ International-presentation

Kei Hayashi

2019/05/17
白色中性子ホログラフィーによる熱電材料BドープMg2Siの研究

杉本和哉, 上地昇一, 金澤雄輝, 福本陽平, 山本隆文, 大山研司, 林好一, 八方直久, 原田正英, 及川健一, 稲村康弘, 林慶, 齋藤亘, 宮﨑讓

日本物理学会第74回年次大会　2019/03/15
単結晶作製時の圧力変化によるMg2Snの格子欠陥制御

齋籐亘, 林慶, 宮﨑讓

第66回応用物理学会春季学術講演会　2019/03/10
Determination of dopant position of thermoelectric material B-doped Mg2Si by white neutron holography International-presentation

K. Sugimoto, S. Uechi, Y. Kanazawa, Y. Fukumoto, T. Yamamoto, K. Ohoyama, K. Hayashi, N. Happo, M. Harada, K. Oikawa, Y. Inamura, K. Hayashi, W. Saito, Y. Miyazaki

ISSP - J-PARC Joint Workshop on Science Frontier by Neutron Scattering ～ The 17th Korea-Japan meeting on Neutron Science ～　2019/01/15
ペロブスカイト型水素化物CaTiO3-xHxの合成と熱電特性

福留大輝, 高松智寿, 林慶, 宮﨑讓

応用物理学会東北支部第73回学術講演会　2018/12/06
Mg2Snの結晶構造と伝導型の関係に関する研究

齋藤亘, 林慶, 宮﨑讓

応用物理学会東北支部第73回学術講演会　2018/12/06
白色中性子ホログラフィーによる熱電材料BドープMg2Siの研究

杉本和哉, 上地昇一, 金澤雄輝, 福本陽平, 山本隆文, 大山研司, 林好一, 八方直久, 原田正英, 及川健一, 稲村康弘, 林慶, 齋藤亘, 宮﨑讓

日本中性子科学会第18回年会　2018/12/04
Structure and thermoelectric properties of Zn4Sb3 International-presentation Invited

Kei Hayashi, Aisaku Yokoyama, Yuzuru Miyazaki

Tsinghua U & Tohoku U Joint Seminar on Thermoelectric Materials　2018/11/05
マグネシウムシリサイド熱電材料における活性サイトの研究

林慶, 齋藤亘, 宮﨑讓, 杉本和哉, 上地昇一, 金澤雄輝, 福本陽平, 山本隆文, 大山研司, 林好一, 八方直久, 原田正英, 及川健一, 稲村康弘

第8回成果報告会　2018/10/14
白色中性子ホログラフィーによる熱電材料BドープMg2Siの研究

杉本和哉, 上地昇一, 金澤雄輝, 福本陽平, 山本隆文, 大山研司, 林好一, 八方直久, 原田正英, 及川健一, 稲村康弘, 林慶, 齋藤亘, 宮﨑讓

第8回3D活性サイト科学成果報告会　2018/10/13
PLD 法によるCrSi2薄膜の作製と熱電特性

安里祐輝, 高松智寿, 飯島喜彦, 林慶, 宮﨑讓

第15回日本熱電学会学術講演会　2018/09/14
ヒドリド(H-)を含有したATiO3-xHx(A=アルカリ土類元素) の熱電特性に関する研究

福留大輝, 高松智寿, 林慶, 宮﨑讓

第15回日本熱電学会学術講演会　2018/09/14
還元拡散法と高温熱処理によるC40型(Cr,Mo)Si2のMo固溶限の拡大と熱電特性

髙松智寿, 中沢駿仁, 飯島喜彦, 林慶, 宮﨑讓

第15回日本熱電学会学術講演会　2018/09/13
Mn2V(Al1-xSix)の熱電特性における規則度の影響

李和章, 林慶, 宮﨑讓

第15回日本熱電学会学術講演会　2018/09/13
溶融合成したMnSiγ の高温X線回折

川崎優太郎, 濱田陽紀, 林慶, 宮﨑讓

第15回日本熱電学会学術講演会　2018/09/13
溶融合成したCr 置換マンガンシリサイドの微細組織と熱電特性

永井宏樹, 林慶, 宮﨑讓

第15回日本熱電学会学術講演会　2018/09/13
Mg2Snの伝導型と結晶構造に対する格子欠陥の効果

齋藤亘, 林慶, 宮﨑讓

第15回日本熱電学会学術講演会　2018/09/13
Structural analysis of β- and γ-phases of Zn4Sb3 thermoelectrics International-presentation

Kei Hayashi, Aisaku Yokoyama, Yuzuru Miyazaki

37th International and 16th European Conference on Thermoelectrics　2018/07/03
Microstructure and thermoelectric properties of magnesium silicide composites International-presentation Invited

K. Hayashi

World Congress of Smart Materials 2018　2018/03/06
Fabrication of (Mn,Fe)Siγ~1.7 thin films for near-infrared absorption solar cells International-presentation

K. Hayashi, K. Ishii, C. Kawasaki, R. Honda, Y. Miyazaki

The 27th International Photovoltaic Science and Engineering Conference PVSEC-27　2017/11/12

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The 27th International Photovoltaic Science and Engineering Conference PVSEC-27 (November 12-17, 2017, Ohtsu) "Fabrication of (Mn,Fe)Siγ~1.7 thin films for near-infrared absorption solar cells" K. Hayashi, K. Ishii, C. Kawasaki, R. Honda, Y. Miyazaki (Poster)
Electronic structure and thermoelectric properties of ternary full-Heusler compounds International-presentation Invited

Kei Hayashi

Global Congress of Knowledge Economy 2017　2017/09/19
フルホイスラー合金Co2MnSiのキャリア熱伝導率と格子熱伝導率

林慶, 宮﨑讓

第78回応用物理学会秋季学術講演会　2017/09/05
東北支部リフレッシュ理科教室の取り組みについて

林慶, 小澤祐市, 矢代航, 佐藤俊一

第78回応用物理学会秋季学術講演会　2017/09/05
Comprehensive study on the thermoelectric properties of Co2MnSi and Co2FeSi International-presentation

Kei Hayashi, Mao Eguchi, Yuzuru Miyazaki

The 36th International Conference on Thermoelectrics ICT2017　2017/07/31
(3+1)-dimensional Incommensurately Modulated Crystal Structure: X-ray Diffraction Study International-presentation Invited

Kei Hayashi

AnalytiX2017　2017/03/22
Mn基フルホイスラー合金の熱電性能計算

林慶, 宮﨑讓

第64回応用物理学会春季学術講演会　2017/03/14
溶融合成によるV, Fe共置換MnSiγの作製と熱電性能

佐藤美嘉, 濱田陽紀, 林慶, 宮﨑讓

第64回応用物理学会春季学術講演会　2017/03/14
Mg2Si系熱電材料の格子欠陥

林慶

熱電材料構造科学セミナー　2016/12/26
Promising thermoelectric properties of melt-grown Zn4Sb3 Zintl phase International-presentation Invited

Kei Hayashi, Aisaku Yokoyama, Kentaro Ishii, Yuzuru Miyazaki

EMN (Energy Materials Nanotechnology) Meeting on Energy and Sustainability 2016　2016/11/28

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HOTEL MYSTAYS Shin Osaka Conference Center
ジントル化合物Zn4Sb3熱電変換材料の高性能化

林慶, 横山相朔, 石井健太郎, 髙松智寿, 宮﨑讓

粉体粉末冶金協会平成28年度秋季大会　2016/11/09

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粉体粉末冶金協会平成28年度秋季大会(第118回講演大会) (11月9-11日, 2016年, 仙台市) "ジントル化合物Zn4Sb3熱電変換材料の高性能化" 林慶, 横山相朔, 石井健太郎, 髙松智寿, 宮﨑讓 (口頭発表)
イントロダクトリートーク～熱電変換の現在と未来：ZTはどこまで上がるのか？～

林慶

第77回応用物理学会秋季学術講演会　2016/09/13
Structural and thermoelectric properties of TTF-I0.71 organic compound International-presentation

Kei Hayashi, Kento Kuba, Yuzuru Miyazaki

The 2016 Compound Semiconductor Week (CSW2016)　2016/06/26
Structural and Thermoelectric Properties of Ternary Full-Heusler Alloys International-presentation

M. Eguchi, K. Hayashi, Y. Miyazaki

The 35th International Conference & the 1st Asian Conference on Thermoelectrics (ICT/ACT 2016)　2016/05/29
Effects of interstitial Mg and secondary phases on thermoelectric properties of Mg2Si International-presentation Invited

Kei Hayashi, Masataka Kubouchi, Yohei Ogawa, Yuzuru Miyazaki

The 2016 EMN (Energy Materials Nanotechnology) Beijing Meeting　2016/04/21
Pyroelectric Energy Harvesting Using BaTiO3 Compounds International-presentation

K. Hayashi, E. Aikawa, T. Ueno, T. Kajitani, Y. Miyazaki

19th International Conference on Ternary and Multinary Compounds　2014/09/01
Preparation of TTF-Ix Thin Films by Evaporation Method for Organic Thermoelectric Devices International-presentation

Kei Hayashi, Kento Kuba, Yuzuru Miyazaki

IUMRS International Conference in Asia 2014　2014/08/24
Structural and pyroelectric properties of Ca-doped BaTiO3 International-presentation

K. Hayashi, E. Aikawa, T. Ueno, T. Kajitani, Y. Miyazaki

The 32nd International Conference on Thermoelectrics　2013/06/30
Anisotropy in thermoelectric properties of MnSiγ film International-presentation

K. Hayashi, K. Takeda, Y. Kikuchi, Y. Miyazaki, T. Kajitani

IUMRS International Conference on Electronic Materials 2012　2012/09/23
Structural, magnetic, and ferroelectric properties of CuFe1-xMnxO2 International-presentation

K. Hayashi, R. Fukatsu, T. Nozaki, Y. Miyazaki, T. Kajitani

The International Workshop on Neutron Applications on Strongly Correlated Electron Systems 2011　2011/02/23
マルチフェロイックCuFe1-xMnxO2の中性子準弾性散乱 Invited

林慶, 深津遼平, 野崎友大, 宮﨑讓, 梶谷剛

ISSPワークショップ小角・反射率・高分解能装置研究会　2011/02/07
Thermoelectric properties of iodine doped pentacene thin films International-presentation

Kei Hayashi, Takashi Shinano, Yuzuru Miyazaki, Tsuyoshi Kajitani

The 37th International Symposium on Compound Semiconductors　2010/05/31
ヨウ素ドープしたペンタセン薄膜の熱電特性とその経時変化

林慶, 信野高志, 梶谷剛

第70回応用物理学会学術講演会　2009/09/08
ラビング基板上に成膜したTTF-TCNQ薄膜の膜構造と熱電特性

林慶, Efrain Tamayo, 梶谷剛

第六回日本熱電学会学術講演会　2009/08/10
三角格子反強磁性体CuFeO2の中性子準弾性散乱

林慶, 野崎友大, 深津遼平, 梶谷剛

拡大IRT研究会シリーズ -3号炉の将来計画を視野に入れて-　2009/08/04
Surface Morphology and Thermoelectric Properties of Copper Phthalocyanine Thin Films on Si(001)

K. Hayashi, T. Shinano, T. Kajitani

The IUMRS International Conference in Asia 2008　2008/12/09
Structure and thermoelectric properties of delafossite-type oxides CuCr0.97-xMg0.03NixO2 International-presentation

K. Hayashi, K. Sato, T. Kajitani

7th Pacific Rim Conference on Ceramic and Glass Technology　2007/11/11
Fabrication and in-plane electrical resistivity of Ge/SiGe quantum dot superlattices International-presentation

K. Hayashi, S. Abiko, N. Motegi, T. Kajitani

20th International Microprocesses and Nanotechnology Conference　2007/11/05
デラフォサイト型酸化物CuCrO2の熱電特性におけるダブルドーピング効果

佐藤健一, 林慶, 梶谷剛

2007年春季第54回応用物理学関係連合講演会　2007/03/27
CO/Cu(001)表面の超低速光電子スペクトル：FR modeの励起によるエネルギー損失構造

林慶, 荒船竜一, 上田茂典, 上原洋一, 潮田資勝

2006年秋季第67回応用物理学会学術講演会　2006/08/29
Vibrational energy loss structure in very low energy photoelectron spectra of CO/Cu(001) surface International-presentation

K. Hayashi, R. Arafune, S. Ueda, Y. Uehara, S. Ushioda

American Physical Society March Meeting 2005　2005/03/21
Cu単結晶表面の低速光電子分光

荒船竜一, 林慶, 上田茂典, 潮田資勝

日本物理学会第58回年次大会　2003/03
Fe/Rh(001)のスピン電子状態の温度依存性(II)

林慶, 原沢あゆみ, 木下豊彦, 柿崎明人

日本物理学会 2001年秋季大会　2001/09
Pd(001)とRh(001)表面上に成長させたFe薄膜の構造と磁性

林慶, 奥田太一, 木下豊彦, 柿崎明人

日本物理学会 2001年秋季大会　2001/09
Structure and magnetism of Fe thin films on Rh(001) studied by spin-resolved photoelectron spectroscopy International-presentation

M. Sawada, A. Harasawa, A. Kimura, A. Kakizaki

PES2000　2000/10
Fe/Rh(001)の温度依存スピン電子状態

林慶, 沢田正博, 原沢あゆみ, 森本理, 柿崎明人

日本物理学会第55回年次大会　2000/09
Thickness dependence of electronic structure and magnetism of Fe/Rh(001) International-presentation

K. Hayashi, M. Sawada, A. Harasawa, A. Kimura, A. Kakizaki

Eight International Conference on Electronic Spectroscopy and Structure (ICESS8)　2000/08
Fe/Rh(001)の構造と電子状態

林慶, 沢田正博, 原沢あゆみ, 木村昭夫, 柿崎明人

日本物理学会 1999年秋の分科会　1999/09
Growth of Fe films on Rh(001): a photoemission study International-presentation

K. Hayashi, M. Sawada, A. Kimura, A. Harasawa, A. Kakizaki

First Vacuum and Surface Sciences Conference of Asia and Australia (VASSCAA-1)　1999/09
Fe/Rh(001)およびFe/Co(001)の成長モードと電子状態

林慶, 沢田正博, 木村昭夫, 鎌倉望, 原沢あゆみ, 柿崎明人

日本物理学会 1998年秋の分科会　1998/09
Fe/Rh(001)の角度分解光電子分光

林慶, 沢田正博, 木村昭夫, 鎌倉望, 原沢あゆみ, 柿崎明人

日本物理学会 1998年秋の分科会　1998/09
格子欠陥を導入したMg2Sn単結晶の熱電性能 International-coauthorship Invited

林慶

第55回排熱発電コンソーシアム　2024/01/19
格子欠陥エンジニアリングによるMg2Sn単結晶の熱電性能の向上 Invited

林慶

JSAP Review創刊記念 VRシンポジウム　2022/11/11

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Industrial Property Rights 11

熱電材料および熱電材料の製造方法

齋藤亘, 林慶, 黄志成, 宮﨑讓

特許第7637969号

Property Type: Patent

Holder: 国立大学法人東北大学
熱電材料および熱電材料の製造方法

宮﨑讓, 林慶, 湯葢邦夫, 濱田陽紀, 佐藤美嘉

特許第7493817号

Property Type: Patent
熱電材料および熱電材料の製造方法

宮﨑讓, 林慶, 湯葢邦夫, 濱田陽紀, 佐藤美嘉

特許第7121964号

Property Type: Patent
希土類アルミノボライド熱電半導体、その製造方法及びそれを用いた熱電発電素子

森孝雄, 丸山恵史, 宮﨑讓, 梶谷剛, 林慶

特許第6061272号

Property Type: Patent
熱電変換材料および熱電変換モジュール

黒崎洋輔, 籔内真, 早川純, 宮﨑讓, 髙松智寿, 林慶

Property Type: Patent
スズ亜鉛シリカリン酸塩系ガラスおよび高温環境用ガラス封止材料

豊原梨恵, 高橋儀宏, 藤原巧, 梶谷剛, 宮﨑讓, 林慶, 上野知道, 上野亨, 山田聖

Property Type: Patent
熱電変換素子

上野亨, 上野知道, 清野嘉幸, 梶谷剛, 宮﨑讓, 林慶, 藤原巧, 井原梨恵

Property Type: Patent
p型熱電変換材料及びその製造方法、並びに、熱電変換素子及び熱電変換モジュール

菊池将太, 林慶, 梶谷剛, 宮﨑讓

特許第5931413号

Property Type: Patent
熱電材料および熱電材料の製造方法

林慶, 竹内裕人, 黄志成, 宮﨑讓

Property Type: Patent
Thermoelectric Conversion Material and Thermoelectric Conversion Module

Yosuke Kurosaki, Shin Yabuuchi, Jun Hayakawa, Yuzuru Miyazaki, Tomohisa Takamatsu, Kei Hayashi

Property Type: Patent
Thermoelectric material and method for producing thermoelectric material

Y. Miyazaki, K. Hayashi, K. Yubuta, H. Hamada, M. Sato

Property Type: Patent

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Research Projects 22

低熱伝導と高強度を両立する鉄基ハーフホイスラー熱電材料のボンドエンジニアリング

宮崎讓, 林慶

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 基盤研究(A)

Institution: 東北大学

2023/04/01 - 2027/03/31
Development of single-crystalline thermoelectric materials with low thermal conductivity via pressure-induced point-defects engineering Competitive

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2022/04/01 - 2025/03/31
自動車排熱・産業排熱を利用した大規模熱電発電のための大型単結晶熱電材料の開発

林慶

Offer Organization: 住友金属鉱山株式会社

System: 共同研究

Category: 共同研究

2020/04 - 2025/03
Achieving minimum thermal conductivity in higher manganese silicide-based thermoelectric materials through controlling of incommensurate nano-sized domains

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2020/04/01 - 2023/03/31
Development of metal/Mg2Si composite materials with high thermoelectric efficiency

HAYASHI Kei

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2017/04/01 - 2020/03/31

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We prepared composite thermoelectric materials consisting of Mg2Si and metal to enhance power factor PF and dimensionless figure-of-merit zT of Mg2Si. As a metal, Mg, Al, and Ni were selected. According to the effective-medium theory, it was predicted that PF and zT are enhanced for all these metals; however, it is valid for the Mg/Mg2Si and Al/Mg2Si composite materials. In the case of Ni, PF and zT decreased by preparing the Ni/Mg2Si composite material. This is due to difference in microstructures and barrier heights at the interface between Mg2Si and metal. The maximum zT value of 0.6 (800 K) was obtained for the Al/Mg2Si composite material by the refinement of the microstructure of the dispersed Al metal phase in Mg2Si, which lead to increase in electrical conductivity and decrease thermal conductivity. This value was higher than an partially Al-substituted Mg2Si materials.
高効率熱電材料の開発 Competitive

林慶

Offer Organization: 住友金属鉱山株式会社

System: 受託研究

Category: 受託研究

2019/11 - 2020/03
階層的構造制御によるチムニーラダー型熱電変換材料の高性能化 Competitive

宮﨑讓

Offer Organization: NEDO

System: 未利用熱エネルギー革新的活用技術研究開発

2015/08 - 2020/03

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階層的構造制御により、熱伝導率を低減し、チムニーラダー型熱電変換材料の高性能化を狙う。
Fabrication of higher-manganese-silicide thin films for near-infrared absorption solar cells

Hayashi Kei, ISHII kentaro, KAWASAKI chihiro, HONDA ryosuke, YANG runchen

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Research (Exploratory)

Institution: Tohoku University

2017/06/30 - 2019/03/31

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We measured optical bandgap and carrier density of Mn1-xFexSig~1.73. Mn1-xFexSig~1.73 thin films were fabricated by using a pulsed laser deposition method. The optical bandgap of Mn1-xFexSig~1.73 thin films was approximately 0.8 eV, which was in the near-infrared (NIR) energy range. The carrier density of a Mn1-xFexSig~1.73 bulk sample (x = 0.28) was approximately 1×10{17} cm-3, which was enough to absorb NIR light up to 90%. To fabricate p-n junction of Mn1-xFexSig~1.73, we attempted to prepare a Mn1-xFexSig~1.73 single crystal that can be used as a substrate, by means of a melt-grown method. Mn1-xFexSig~1.73 single crystals were successfully obtained in the range of x < 0.2. Using the p-type Mn1-xFexSig~1.73 single crystal (x = 0.15), we could grow n-type Mn1-xFexSig~1.73 thin films.
格子間活性サイトエンジニアリングの開拓と熱電発電材料・デバイス開発への応用展開

宮崎讓

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 新学術領域研究(研究領域提案型)

Institution: 東北大学

2017/04/01 - 2019/03/31

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溶融合成法とブリッジマン法を用いて、熱電発電材料として注目されているマグネシウムシリサイド(Mg2Si)、マグネシウムスタナイド(Mg2Sn)、およびそれらにホウ素(B)をドープした試料の大型単結晶を育成した。これにより、中性子ホログラフィーによる局所原子構造の解析と、単結晶X線回折を用いた格子欠陥量の定量評価が可能となった。続いて、実際にMg2SiにドープしたBの周辺の局所原子構造を調査し、BがMgサイトに侵入して活性化することを明らかにした。また、Mg2Sn単結晶を育成する時の雰囲気を変化させることで、Mg2Sn単結晶に含まれるMg正規サイト(MgR)の欠損量を制御できることを明らかにした。並行して、単結晶試料の熱電特性（ゼーベック係数、導電率および熱伝導率）の温度変化を測定し、Bドープ量と熱電特性の間に強い相関があることが確認された。従来、Mg2(Si1-xSnx)熱電発電材料の性能向上は、部分置換や元素添加によってキャリア密度を制御して行われてきた。本研究成果は、部分置換あるいは添加した元素がどのサイトに入って活性化しているのか、中性子ホログラフィーによって可視化できることを示したものであり、漫然と試みられてきたMg2(Si1-xSnx)の性能向上の研究に革新をもたらすものと期待される。また、本研究で明らかになったMgR欠損量の制御法は、格子欠陥を有する熱電発電材料の開発研究の指針として有用な知見となるものと考えられる。
高電流出力熱電発電デバイス用のハーフメタル強磁性フルホイスラー合金の開発 Competitive

林慶

Offer Organization: 熱・電気エネルギー技術財団

System: 研究助成(一般研究)

2017/01 - 2018/02

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高電流出力熱電発電デバイス用の金属熱電材料を開発する。
Fabrication of high performance thermoelectric devices using incommensurate chimney ladder compounds

Miyazaki Yuzuru, HAYASHI Kei, TAKAMATSU Tomohisa

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2013/04/01 - 2016/03/31

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Higher manganese silicide-based chimney-ladder compounds have been prepared and detailed crystal structure of four new phases has been determined. Metallic composition to realize potential thermoelectric (TE) properties has been investigated and the best p-type performance has been achieved for a lightly vanadium-substituted samples. A 3cm x 3cm size TE module has been fabricated and its power generation has been measured under a temperature difference of 400 K. The highest output power of 1.3 W has been recorded, which corresponds to the power density of 1.25 kW/m2.
Thermoelectric properties and performance of molecular organic compounds

Hayashi Kei

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: Tohoku University

2013/04/01 - 2016/03/31

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To reduce the consumption of energy resources and prevent the emission of global warming gasses, thermoelectric conversion technique has been attracted much attention as a clean power generation system. In this study, we focused on molecular organic compounds as a thermoelectric material. Pentacene, tetrathiafulvalene-tetrachianoquinodimethane (TTF-TCNQ), and TTF-Ix thin films were fabricated and their thermoelectric properties were measured. In addition, we evaluated electric power generated from these organic thin films by measuring current-voltage characteristics.
Fabrication of cooling devices by means of the Thomson effect

MIYAZAKI Yuzuru, HAYASHI Kei

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2013/04/01 - 2015/03/31

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Experimental conditions to fabricate solids wherein the carrier concentration consecutively and exponentially changes in order to realize cooling devices utilizing the Thomson effect. Partially Fe-substituted manganese silicides known as degenerated semiconductors have been selected. The amount of Fe-substitution and its distribution were controlled by the spark plasma sintering temperature and duration time. A discernible voltage was detected when the temperature gradient and electric current were applied to the samples. However, it was difficult to separate the contributions of the Seebeck, Peltier and Thomson effects. Besides, a novel phenomenon to generate electric power from no temperature difference has been detected. This effect would useful as a new power generation method from waste heat without cooling parts.
Development of High Efficient Pyroelectric Generator

KAJITANI Tsuyoshi, HAYASHI Kei

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2012/04/01 - 2014/03/31

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This project was aimed to develop practically usable pyroelectric device materials for the low temperature waist heat harvesting. Research focus was to develop modified BTO which has low Curie temperature, at about 130 deg., and temperature dependent polarization, P(T). The first principle band calculation was repeated to find suitable combination of ionic arrangement and crystal structure suitable for the purpose. Following itemized knowledges were obtained. 1.Partial substitution of Y or Ca for Ba caused appreciable increase in Curie temperature. for 5 deg. was due to the substitution of Y or Ca. 2.The polarization, P, also increased by the partial substitution. 3. Significant increase in the grain sizes and pyroelectric coefficient were recorded for the 30% Ca sample. 4. The d-bands extended from Ti, Zr or Nb ion situated just below Fermi level have very close relationship between the pyroelectric characteristics of above three materials.
多層高効率熱電デバイスの製造 Competitive

梶谷剛

Offer Organization: 経済産業省

System: 戦略的基盤技術高度化支援事業

2010/10 - 2013/03

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高い出力密度(＝熱効率／実装密度)を実現する多層熱電デバイスの製造を目的とする。従来の熱電デバイスと比べて、機械的強度、耐酸化性、耐湿度を高めるとともに、製造価格を大幅に低減する。本熱電デバイスは、NOx除去装置から出た400℃～600℃の高熱排気ガスを熱源とし発電する画期的な熱回生装置への応用を目標とする。
Basic research on future thermoelectric device using spinSeebeck effect

HAYASHI Kei

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Young Scientists (B)

Institution: Tohoku University

2011 - 2012

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We have studied spin Seebeck effect of half metal compounds, Co_2CrAl, Co_2Cr_<1-x>Fe_xAl, and Co_2Cr_<1-x>Mn_xAl. The spin Seebeck voltage changed with substitution amount x, indicating the relation between the voltage and saturation magnetization.
層状コバルト酸化物熱電材料の研究開発 Competitive

梶谷剛

Offer Organization: 日本ガイシ(株)

System: 受託研究

2010/09 - 2011/03

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層状コバルト酸化物Co121にナノサイズの空孔あるいは不純物を導入し、ナノスケールの組織制御を行うことで熱伝導率を低減する。これによりZT=1を目指す。
π型積層構造を有する薄膜太陽光熱複合発電モジュールの開発 Competitive

林慶

Offer Organization: 東電科学技術研究所

System: 研究助成(一般研究)

2010/04 - 2011/03

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薄膜太陽光発電モジュールの構造をπ型積層構造にすることで、太陽熱発電が同時に起こるようにし、熱効率の飛躍的な向上を目指す。
Development of Dimension-Controlled Narrow-gap Semiconductor Devices

KAJITANI Tsuyoshi, FUJIWARA Takumi, MIYAZAKI Yuzuru, HAYASHI Kei, YUBUTA Kunio

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2007 - 2010

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This project was aimed to develop high performance thermoelectric devices which can directly convert the heat flux to the electrical current. Theoretically, it has been expected that the dimensional controlling, namely developing the two-dimensional device, i. e. thin layered devices as well as two-dimensional layered synthetic crystals might exhibit enhanced thermoelectric performance. Recently, one paper showed that high-performance 2D-device ; i. e., being 2. 5 times high relative to the 3D one, was developed. In this project, thin pulsed laser deposition films, vacuum evaporation films and synthetic layered semiconductors were studied.
Fundamental study on fabrication of highly-oriented organic thinfilms with high thermoelectric performance

HAYASHI Kei

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Young Scientists (B)

Institution: Tohoku University

2007 - 2009

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We have attempted to fabricate highly-oriented organic thin films such as copper phthalocyanine, tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ), and pentacene by the use of vicinal substrates, oblique evaporation technique, and rubbing method. As a result, we have succeeded to realize highly flat TTF-TCNQ thin films with the power factor of 7.8×10^<-7> W/mK^2. In addition, the iodine-doped pentacene thin films shows the higher power factor of 2×10^<-5> W/mK^2.
電子内部自由度制御型ナノデバイス創製原理の構築 Competitive

前川禎通

Offer Organization: 科学技術振興機構

System: 戦略的創造研究推進事業

2007/04 - 2008/03

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多体電子系の様々な数値計算法を用いて、強相関電子系における競合する相の関係を明らかにし、その競合から生じる新奇な量子現象を引き出すとともに、それらを用いたナノデバイスの特性を解き明かすことを目的とする。そして、実験的実証を踏まえながら新しいナノデバイスの創製指導原理を構築しようとするものである。
ナノブロックインテグレーションによる層状酸化物熱電材料の創製 Competitive

河本邦仁

Offer Organization: 科学技術振興機構

System: 戦略的創造研究推進事業

2006/04 - 2008/03

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環境負荷を最大限に低減する環境保全・エネルギー高度利用の実現のためのナノ材料・システムを創製する。

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Teaching Experience 9

電磁気学基礎演習 Undergraduate (specialized)
構造物性学 Postgraduate
数学物理学演習II Undergraduate (specialized)
電磁気学基礎論 Undergraduate (specialized)
学生実験 Undergraduate (specialized)
応用材料物性学 Postgraduate
応用物理学特別研修 Postgraduate
電磁気学I演習 Undergraduate (specialized)
応物研修 Undergraduate (specialized)

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Social Activities 36

20周年記念リフレッシュ理科教室

2019/01/26 - 2019/01/26

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生涯学園都市会館(花巻市)にて20周年記念リフレッシュ理科教室を実施した。
平成30年度サイエンススクール(仙台市立連坊小路小学校)

2018/12/18 - 2018/12/18
平成30年度サイエンススクール(仙台市立金剛沢小学校)

2018/12/17 - 2018/12/17
平成30年度サイエンススクール(仙台市立桂小学校)

2018/12/11 - 2018/12/11
20周年記念リフレッシュ理科教室

2018/08/22 - 2018/08/22

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弘前大(弘前市)にて20周年記念リフレッシュ理科教室を実施した。
20周年記念リフレッシュ理科教室

2018/08/21 - 2018/08/21

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秋田大(秋田市)にて20周年記念リフレッシュ理科教室を実施した。
20周年記念リフレッシュ理科教室

2018/08/10 - 2018/08/10

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山形大(米沢市)にて20周年記念リフレッシュ理科教室を実施した。
20周年記念リフレッシュ理科教室

2018/08/01 - 2018/08/01

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ビックアイ(郡山市)にて20周年記念リフレッシュ理科教室を実施した。
20周年記念リフレッシュ理科教室

2018/07/29 - 2018/07/29

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サイエンスディ(仙台市)にて20周年記念リフレッシュ理科教室を実施した。
平成29年度サイエンススクール(上愛子小学校)

2017/12/18 - 2017/12/18

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上愛子小学校にて大学出前講座を行った
平成29年度サイエンススクール(福室小学校)

2017/12/14 - 2017/12/14

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福室小学校にて大学出前講座を行った
平成29年度サイエンススクール(仙台青陵中等教育学校)

2017/12/12 - 2017/12/12

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仙台青陵中等教育学校にて大学出前講座を行った
平成29年度大学出前講座(大田原高等学校)

2017/10/10 - 2017/10/10

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大田原高等学校にて大学出前講座を行った
工作や実験大好き市科学館子ども理科教室

2017/08/06 - 2017/08/06
リフレッシュ理科教室(応用物理学会東海支部リフレッシュ理科教室20周年記念事業)

2017/08/03 - 2017/08/05

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名古屋市科学館にてリフレッシュ理科教室を実施単極モーターを小中学校の先生と子どもたちに実施
リフレッシュ理科教室part2

2017/07/29 - 2017/07/29

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2017年7月29日に東北学院大学ハイテクリサーチセンター/工学部1号館ラウンジでリフレッシュ理科教室を開催応用物理学会東北支部企画運営委員会幹事として実施
リフレッシュ理科教室part1

2017/07/16 - 2017/07/16

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2017年7月15日に東北大学川内キャンパス講義棟でリフレッシュ理科教室を開催応用物理学会東北支部企画運営委員会幹事として実施
リフレッシュ理科教室part1

2016/04/01 - 2016/08/22

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2016年8月22日に東北大学創造工学センターでリフレッシュ理科教室を開催応用物理学会東北支部企画運営委員会幹事として参加
サイエンスディ

2016/04/01 - 2016/07/28

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2016年7月17、22日のサイエンスディに応用物理学会東北支部の出展を応用物理学会東北支部企画運営委員会幹事として実施
リフレッシュ理科教室

2012/08/22 - 2013/07/09

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2013年6月28日に中野小学校でリフレッシュ理科教室を開催応用物理学会東北支部・東海支部・九州支部主催実行委員として参加
第73回東北大学祭模擬講義

2021/11/05 -
令和2年度一日大学(仙台青陵中等教育学校)

2020/11/06 -
平成29年度大学出前講座(盛岡中央高等学校)

2017/07/07 -

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盛岡中央高等学校にて大学出前講座を行った
排熱を電力へ、熱電変換材料で2倍の出力因子実現

2016/12/05 -

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東北大学の宮崎讓氏、林慶氏らの研究グループは2016年12月、マンガンケイ化物系熱電変換材料の発電量を表す出力因子で、従来の1.6～2倍に相当する結果を得たと発表した。
東北大学、車の排熱など無駄な熱を電気エネルギーに換える熱電発電モジュールの実現が視野に

2016/12/02 -

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東北大学大学院工学研究科は1日、自動車エンジンや工場排熱など、300～700℃の未利用熱エネルギーを電力に変換するための熱電変換技術において、マンガンケイ化物系熱電変換材料を使用し、従来の約2倍に相当する2.4mW/平方Kmを実現したと発表した。
発電量を2倍に、排熱を電力に変換する新材料

2016/12/02 -

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東北大学の研究グループがNEDOプロジェクトの一環で、マンガンケイ化物を用いた新しい熱電変換材料を開発。低コストな材料を用いつつ、発電量の指標となる出力因子を従来比約2倍に高めた。自動車エンジンの排熱や工業炉からの排熱など、中温域の未利用熱を電力に変換する高出力な熱電発電モジュールの実現に貢献する成果だという。
出力因子従来比約2倍のマンガンケイ化物系熱電変換材料、高温未利用熱エネルギーの活用へ

2016/12/02 -

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東北大学の宮崎讓氏、林慶氏らの研究グループは2016年12月、マンガンケイ化物系熱電変換材料の発電量を表す出力因子で、従来の1.6～2倍に相当する結果を得たと発表した。
マンガンケイ化物系熱電変換材料で、従来比2倍の出力を実現

2016/12/02 -

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東北大学は2016年12月1日、マンガンケイ化物系熱電変換材料で、発電量を表す指標である出力因子として、従来の約2倍に相当する2.4mW/K2mを達成したと発表した。自動車エンジンや産業分野の工業炉からの排熱など、300～700℃の未利用熱エネルギーを電力に変換する高出力熱電発電モジュールの実現が期待される。
リフレッシュ理科教室part2

2016/11/05 -

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2016年11月5日に東北大学知の館でリフレッシュ理科教室を開催応用物理学会東北支部企画運営委員会幹事として参加
東北大学出張講座

2016/09/21 -

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河合塾仙台校にて東北大学出張講座を行った
磁石の力にわくわく仙台・中野小応用物理学会が理科教室

2013/07 -
物理学者が被災小学校で理科教室

2013/06 -
被災小学校で理科教室

2013/06 -
排熱から電気変換効率40倍

2012/05/21 -
東北大、マンガン・ケイ素製の多層型熱電デバイスの試作品を展示

2012/03/19 -

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東北大学大学院工学研究科応用物理学専攻の梶谷剛教授の研究グループは、マンガン・ケイ素系製熱電材料シートを積層した多層型デバイスの試作品を公表した。2012年3月15日に東北大学産学連携推進本部が東京都千代田区で開催した「東北大学イノベーションフェア」で展示したもの。
東北大学イノベーションフェア2006 in 仙台

2006/10/18 -

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東北大学イノベーションフェア2006 in 仙台にて展示した

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Media Coverage 33

熱電材料として「Mg2Sn単結晶」が実用レベルに

EE Times Japan

2025/04/03

Type: Internet
東北大、マグネシウム・スズ化合物の熱電性能を実用レベルまで向上

マイナビ　マイナビニュース

2025/04/02

Type: Internet
デバイス化が容易なハーフメタルの熱電性能を４倍向上東北大研究チーム「エネルギーハーベスティング技術の進展が期待」

株式会社官庁通信社　文教速報デジタル版

2024/01/10

Type: Internet
デバイス化が容易なハーフメタルの熱電性能を4倍向上させる方法を確立東北大学と中国清華大学

MEITEC　fabcross for エンジニア

2024/01/09

Type: Internet
デバイス化が容易なハーフメタルの熱電性能を4倍向上 - 点⽋陥制御と部分置換で半導体に匹敵する熱電材料に期待 -

理化学研究所　Q-Portal

2024/01/05

Type: Internet
東北⼤、デバイス化が容易なハーフメタルの熱電性能を4倍向上させることに成功

日本経済新聞社　日経電子版

2024/01/04

Type: Internet
東北大学など、熱電性能の高いマグネシウム・スズ化合物p型単結晶

日経BP　日経XTECH

2023/01/26

Type: Internet
p型でも熱電性能が高いマグネシウムスズ化合物の単結晶を作製東北大学

MEITEC　fabcross for エンジニア

2023/01/16

Type: Internet
性能26倍、東北大などがマグネシウム・スズ化合物の熱電変換性能向上

ニュースイッチ (Yahoo! JAPAN ニュース、goo ニュースに転載)

2023/01/16

Type: Internet
マグネシウム・スズ化合物熱電変換性能高める東北大など

日刊工業新聞社　日刊工業新聞　19面

2023/01/13

Type: Newspaper, magazine
東北大など、マグネシウム・スズ化合物の熱電変換性能向上一部リチウム置換で性能26倍

日刊工業新聞社　日刊工業新聞電子版

2023/01/13

Type: Internet
東北大、有力な熱電材料マグネシウムスズ化合物のp型性能で記録更新

日本経済新聞社　日本経済新聞

2023/01/12

Type: Newspaper, magazine
【連載】コロナ禍の教室 ④理系学生・教員規制緩和で生徒の交流増加

東北大学学友会報道部　東北大学新聞

2022/01/22

Type: Newspaper, magazine
東北大，単結晶の欠陥制御で最低熱伝導率達成

OPTRONICS ONLINE

2021/05/12

Type: Internet
東北大など、化学的圧力で単結晶の欠陥を制御して最低熱伝導率を達成

日本経済新聞社　日経電子版

2021/05/11

Type: Internet
亜鉛アンチモン化合物、100時間加熱でクラック解消東北大

日刊工業新聞社　日刊工業新聞

2021/04/16

Type: Newspaper, magazine
東北大など、熱電変換材の性能50倍システム実現に道

日刊工業新聞社　日刊工業新聞

2020/12/29

Type: Newspaper, magazine
東北大、熱を伝えにくい単結晶で電気を流しやすくすることに成功

日本経済新聞社　日経電子版

2020/12/24

Type: Internet
東北大ら，単結晶の熱電変換材料を開発

OPTRONICS ONLINE

2020/02/26

Type: Internet
高い熱電変換効率を有する単結晶熱電変換材料の開発手法を確立――熱利用のエネルギーハーベスティングの実用化に寄与東北大

fabcross for エンジニア

2020/02/26

Type: Internet
東北大、高効率の単結晶熱電変換材料の開発手法を創出

日本経済新聞社　日経電子版

2020/02/25

Type: Internet
FMアップルウェーブゴゴナビ!! リフレッシュ理科教室生中継

FMアップルウェーブ

2018

Type: TV or radio program
工作や実験大好き市科学館子ども理科教室

中日新聞日曜朝刊愛知県版

2017

Type: Newspaper, magazine
排熱を電力へ、熱電変換材料で2倍の出力因子実現

EE Times Japan

2016

Type: Internet
マンガンケイ化物系熱電変換材料で、従来比2倍の出力を実現

日経テクノロジーonline

2016

Type: Internet
東北大学、車の排熱など無駄な熱を電気エネルギーに換える熱電発電モジュールの実現が視野に

PC Watch

2016

Type: Internet
発電量を2倍に、排熱を電力に変換する新材料

スマートジャパン

2016

Type: Internet
出力因子従来比約2倍のマンガンケイ化物系熱電変換材料、高温未利用熱エネルギーの活用へ

fabcross for エンジニア

2016

Type: Internet
磁石の力にわくわく仙台・中野小応用物理学会が理科教室

河北新報

2013

Type: Newspaper, magazine
被災小学校で理科教室

NHK宮城

2013

Type: TV or radio program
物理学者が被災小学校で理科教室

仙台放送

2013

Type: TV or radio program
東北大、マンガン・ケイ素製の多層型熱電デバイスの試作品を展示

日経テクノロジーonline

2012

Type: Internet
排熱から電気変換効率40倍

日経産業新聞

2012

Type: Newspaper, magazine

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Other 4

機能性無機・有機材料の電子状態および熱・電気輸送特性の計算
焦電発電材料の開発
近赤外光太陽電池材料の開発
無機・有機熱電変換材料の開発