The 4th Symposium for
The Core Research Cluster for
Materials Science andthe 3rd Symposium on
International Joint Graduate Programin Materials Science

10 11 , 2020
“Create New Value of Materials Science through Broad Collaboration”
FebruaryMon

Tue

Sendai International Center

2020

Tohoku University was named one of the first three Designated National Universities in Japan onJune 30, 2017 by the Japanese Government. As a Designated National University, Tohoku University
initiated the Core Research Clusters in four research fields; materials science, spintronics, nextgeneration medical care and disaster science. We will hold the 3rd symposium on the two research
fields, Materials Science and Spintronics to show our research results and discuss future prospects

ProgramSPeakerS CVS
abStraCtS
PoSter abStraCtS

Jerome B. Hastings

SLAC National Accelerator Laboratory

City Hall

Prefectural Office

Jozenji ave.

Koutoudai-koen Sta.

International
Center Sta.

Hirose ave.

Hirose-dori Sta.

Omachi
Nishi-koen Sta.

Sendai International
Center

Aoba-dori
Ichibancho Sta.
Aoba ave.
SubwaySendai Sta.

Bus
Pool

JR
Sendai Sta.

Stéphane Mangin
University of Lorraine

Maki Kawai

Institute for Molecular Science

International Affairs Center（IAC）,
Organization for Advanced Studies, Tohoku University
2-1-1 Katahira, Aoba-ku, Sendai
980-8577, JAPAN
Phone: +81-22-217-5971 Fax: +81-22-217-5129
E-mail: iac@grp.tohoku.ac.jp

Minamimachi ave.

Itsutsubashi Sta.

http://www.wpi-aimr.tohoku.ac.jp/iac/event.html

International CollaborationTohoku
Center, University
Institute for Materials Research, Tohoku University

The 4th Symposium for The Core Research Cluster for Materials Science andthe 3rd Symposium on International Joint Graduate Program in Materials Science
November 16 (Mon) - 18 (Wed), 2020
As of October 28, 2020

Nov. 16 (Mon)

DAY 1
JST
9:00

Core Research Cluster for Materials Science
GP-MS
9:00-9:10 Opening Remarks: OHNO Hideo, President of Tohoku University

9:10
9:20 9:10-9:55 Plenary Session ①
9:30 Chair: KOTANI Motoko

9:40 ・Byeong-Joo Lee (Pohang University of Science and Technology)
9:50
9:55
10:00

9:55-10:00 Remarks: YAMAGUCHI Masahiro, Head of the Division for International Joint Graduate School Programs, Tohoku University
10:00-10:10 Break (10 min.)

10:10
10:20

10:10-11:40<Materials Science> Session 1
Chair: FURUHARA Tadashi
10:50
1-A. OHTANI Hiroshi (Tohoku University)
11:00
1-B. MATSUBAE Kazuyo (Tohoku University)
11:10
1-C. ABE Eiji (The University of Tokyo)
11:20
10:30
10:40

11:30
11:40
11:50
12:00
12:10
12:20

Lunch
(11:40-13:00)

12:30
12:40
12:50
13:00

13:00-14:30<Materials Science> Session 2
Chair: YOSHIMI Kyosuke
13:30
2-A. Qiang Charles Feng (University of Science and Technology
13:40
Beijing)
13:50
2-B. OHMURA Takahito (National Institute for Materials Science)
14:00
2-C. NOMURA Naoyuki (Tohoku University)
14:10
13:10
13:20

14:20
14:30
14:40

14:00-16:00<GP-MS> Student Session 1
Chair: KOSABA Takumi
1-A. Ying Jin (University of Science and Technology Beijing)
1-B. HIROMOTO Sachiko (National institute for Materials
Science)
1-C. KOSABA Takumi (Tohoku University)

14:30-14:50 Break (20 min.)

14:50
15:00

14:50-16:20<Materials Science> Session 3
15:20
Chair: HIRANO-IWATA Ayumi
15:30
3-A. KURIYAGAWA Tsunemoto (Tohoku University)
15:40
3-B. UMETSU Mitsuo (Tohoku University)
15:50
3-C. Yi-tao Long (Nanjing University)
16:00
15:10

16:10
16:20
16:30

16:00-16:40 Break(40min.)16:20-16:40 Break (20 min.)

16:40
16:50 16:40-17:25 Plenary Session ②
17:00 Chair: FURUHARA Tadashi

17:10 ・Dierk Raabe (Max-Planck-Institut für Eisenforschung GmbH)
17:20
17:30

17:25-18:10 Plenary Session ③
Chair: ORIMO Shin-ichi
17:50
・Hans-Joachim Freund (Fritz-Haber-Institut der Max-Planck-Gesellschaft)
18:00
17:40

i

The 4th Symposium for The Core Research Cluster for Materials Science andthe 3rd Symposium on International Joint Graduate Program in Materials Science
November 16 (Mon) - 18 (Wed), 2020

Nov. 17 (Tue)

DAY 2
JST

Core Research Cluster for Materials Science

GP-MS

10:00
10:10

10:00-11:30<Materials Science> Session 4
10:30
Chair: ORIMO Shin-ichi
10:40
4-A. MIZUGUCHI Masaki (Nagoya University)
10:50
4-B. EINAGA Mari (Osaka University)
11:00
4-C. AKAGI Kazuto (Tohoku University)
11:10
10:20

11:20
11:30
11:40
11:50
12:00
12:10
12:20

Lunch
(11:30-13:00)

12:30
12:40
12:50
13:00
13:10
13:20
13:30
13:40
13:50
14:00

Poster Session(13:00-15:00)

14:10
14:20
14:30
14:40
14:50
15:00
15:10
15:20
15:30
15:40
15:50
16:00
16:10
16:20
16:30
16:40
16:50
17:00
17:10

17:00-19:00<GP-MS> Student Session 2
Chair: YAMAGUCHI Mina
2-A. Andreas Klein (Technical University Darmstadt)
2-B. Holger Fritze (Technical University of Clausthal)
2-C. Matthias T. Elm (Justus Liebig University Gießen)
2-D. TAKAMURA Hitoshi (Tohoku University)
2-E. YAMAGUCHI Mina (Tohoku University)

17:20
17:30
17:40
17:50
18:00
18:10
18:20
18:30
18:40
18:50

19:00-19:10 Break (10 min.)

19:00
19:10
19:20
19:30

19:10-21:10<GP-MS> Student Session 3
Chair: KURISU Minoru
3-A. Peter Walde (ETH)
3-B. Dora Tang (Max Planck Institute)
3-C. Kate Adamala (University of Minnesota)
3-D. KURISU Minoru (Tohoku University)

19:40
19:50
20:00
20:10
20:20
20:30
20:40
20:50
21:00

ii

The 4th Symposium for The Core Research Cluster for Materials Science andthe 3rd Symposium on International Joint Graduate Program in Materials Science
November 16 (Mon) - 18 (Wed), 2020

Nov. 18 (Wed)

DAY 3
JST

Core Research Cluster for Materials Science

GP-MS

8:30
8:40
8:50
9:00

9:00-10:30<GP-MS> GP-MS Session
Chair: SAITO Riichiro
A. Shengxi Huang (Pennsylvania State University)
B. Lianming Tong (Peking University)
C. Teng Yang (Institute of Metal Research, Chinese Academy of
Sciences)

9:10

9:00-10:30<Materials Science> Session 5
9:30
Chair: FUKUMURA Tomoteru
9:40
5-A. MURAKAMI Shuichi (Tokyo Institute of Technology)
9:50
5-B. FUJIWARA Kozo (Tohoku University)
10:00
5-C. TSUDA Kenji (Tohoku University)
10:10
9:20

10:20
10:30
10:40
10:50
11:00
11:10

10:30-10:50 Break (20 min.)

10:30-10:50 Break (20 min.)
10:50-11:10 Poster Award Ceremony

11:10-11:20 Closing Remarks: NAGASAKA Tetsuya, Dean of Graduate School of Engineering, Tohoku University

iii

The 4th Symposium for The Core Research Cluster for Materials Science and the 3rd Symposiumon International Joint Graduate Program in Materials Science“Create New Value of Materials Science through Broad Collaboration”

Program & Abstracts
As of October 28, 2020

November 16 (Mon)
Opening Remarks

9:00 - 9:10

OHNO Hideo (President of Tohoku University)�������������2

Plenary Session 1 9:10-9:55
Chair: KOTANI Motoko (Director, Core Research Cluster for Materials Science)�������� 3
Plenary Session 1

9:10-9:55

Remarks

9:55 -10:00
YAMAGUCHI Masahiro (Head, Division for International Joint Graduate
School Programs)���������������������������6

Byeong-Joo Lee (Pohang University of Science andTechnology)“Solute-dislocation binding: understanding themechanism for room temperature ductility of Mg alloys”
�������������������������� 4---------- Parallel Session ---------Session 1 10:10- 11:40
Chair: FURUHARA Tadashi (Director, IMR) ������������������������� 7
Session 1-A

10:10-10:40

OHTANI Hiroshi (IMRAM)“Electron Theory Calculation of Thermodynamic
Properties of Alloys and Its Application to Theoretical
Phase Diagrams” ������������������ 8

Session 1-B

10:40-11:10

MATSUBAE Kazuyo (Graduate School of Environmental
Studies)“Resource logistics approach on critical resources for
future society” ������������������ 10

Session 1-C

11:10-11:40

ABE Eiji (The University of Tokyo)“Kink Strengthening of Mille-feuille Structures in Mg
Alloys” ���������������������� 12iv

Session 2 13:00- 14:30
Chair: YOSHIMI Kyosuke (Professor, Graduate School of Engineering) ������������15
Session 2-A

13:00-13:30

Qiang Charles Feng (University of Science andTechnology Beijing)“Development of γ′-strengthened Co-base superalloys
with improved comprehensive performances”��� 16

Session 2-B

13:30-14:00

OHMURA Takahito (National Institute for Materials
Science)“Characterization of Dislocation Motions in Metallic
Materials by TEM In-situ Straining and Nanoindentation”������������������������� 18

Session 2-C

14:00-14:30

NOMURA Naoyuki (Graduate School of Engineering)“Challenges of composite powder fabrication for additive
manufacturing”������������������ 20

Student Session 1 14:00- 16:00
Chair: KOSABA Takumi (Graduate School of Engineering)Student Session 1-A

Ying Jin (University of Science and Technology Beijing)“High-throughput Characterization Methods for Corrosion Research”

22Student Session 1-B

HIROMOTO Sachiko (National institute for Materials Science)“Calcium Phosphate Coating of Mg/Mg alloys for Biomedical Use” �� 24

Student Session 1-C

KOSABA Takumi (Graduate School of Engineering)“Effect of Anodizing on Galvanic Corrosion Prevention ofPure aluminum Coupled to Pure iron and stainless steel”������� 26

Session 3 14:50- 16:20
Chair: HIRANO-IWATA Ayumi (Professor, AIMR/RIEC) �������������������27
Session 3-A

14:50-15:20

KURIYAGAWA Tsunemoto (Graduate School of
Biomedical Engineering)“Future of High Value Manufacturing (Introduction of BioMedical Applications for the Super Aging Society)” � 28

Session 3-B

15:20-15:50

UMETSU Mitsuo (Graduate School of Engineering)“Protein-based molecular evolution for nanobioengineering” ����������������� 30

Session 3-C

15:50-16:20

Yi-tao Long (Nanjing University)“Electrochemistry Confined Nanopore: Design andApplication in Single Molecule Sensing”������ 32v

Plenary Session 2 16:40-17:25
Chair: FURUHARA Tadashi (Director, IMR) ������������������������� 7
Plenary Session 2

16:40-17:25

Dierk Raabe (Max-Planck-Institut für EisenforschungGmbH)“Interplay of Chemistry and Structure at Lattice Defects
studied at the Atomic Scale”������������ 34

Plenary Session 3 17:25-18:10
Chair: ORIMO Shin-ichi (Director, AIMR) ��������������������������36
Plenary Session 3

17:25-18:10

Hans-Joachim Freund (Fritz-Haber-Institut der MaxPlanck-Gesellschaft)“Model Systems for Heterogeneous Catalysts at theAtomic Scale”������������������� 38

November 17 (Tue)
Session 4 10:00- 11:30
Chair: ORIMO Shin-ichi (Director, AIMR) ��������������������������36
Session 4-A

10:00-10:30

MIZUGUCHI Masaki (Nagoya University)“Nanostructured magnetic materials for thermoelectric
generation”�������������������� 40

Session 4-B

10:30-11:00

EINAGA Mari (Osaka University)“Search for Superconductivity of Super-hydrides
Synthesized under Extreme Condition” ������ 42

Session 4-C

11:00-11:30

AKAGI Kazuto (AIMR)“Collaboration among Computation, Experiments andMathematics toward Next Generation Battery”��� 44

Student Session 2 17:00- 19:00
Chair: YAMAGUCHI Mina (Graduate School of Engineering)Student Session 2-A

Andreas Klein (Technical University Darmstadt)“XPS Analysis of Functional Oxides”����������������� 46

Student Session 2-B

Holger Fritze (Technical University of Clausthal)“High-Temperature Acoustic Loss in Piezoelectric CTGS crystals”��� 48

Student Session 2-C

Matthias T. Elm (Justus Liebig University Gießen)“Impact of the Surface Space Charge Region on the Charge Transport inOxides for Energy Applications”������������������� 50

Student Session 2-D

TAKAMURA Hitoshi (Graduate School of Engineering)“Catalytic Activity of Cobalt-Based Oxides for the Cathodic Reaction of ITSOFC” ������������������������������� 52vi

Student Session 2-E

YAMAGUCHI Mina (Graduate School of Engineering)“Flat Visible-Light Absorption Properties of Inorganic Thin Films Preparedby Pulsed Laser Deposition”��������������������� 54

Student Session 3 19:10- 21:10
Chair: KURISU Minoru (Graduate School of Engineering)Student Session 3-A

Peter Walde (ETH)“Basic Properties of Vesicles as Biomaterials” ������������ 56

Student Session 3-B

Dora Tang (Max Planck Institute)“Bottom up approaches to synthetic cellularity” ����������� 58

Student Session 3-C

Kate Adamala (University of Minnesota)

Student Session 3-D

KURISU Minoru (Graduate School of Engineering)“Sustainable Reproduction of Vesicles coupled with Surface Confined
Template Polymerization”���������������������� 60

November 18 (Wed)Session 5 9:00- 10:30
Chair: FUKUMURA Tomoteru (Professor, AIMR)�����������������������61
Session 5-A

9:00-9:30

MURAKAMI Shuichi (Tokyo Institute of Technology)“Theoretical approaches to topological materials” � 62

Session 5-B

9:30-10:00

FUJIWARA Kozo (IMR)“Morphology of Crystals in Melt Growth Processes” � 64

Session 5-C

10:00-10:30

TSUDA Kenji (FRIS)“Nanometer-scale local crystal structure analysis using
convergent-beam electron diffraction”������� 66

GP-MS Session 9:00- 10:30
Chair: SAITO Riichiro (Professor, Graduate School of Science) ����������������68
GP-MS Session A

Shengxi Huang (Pennsylvania State University)“Abnormal Raman Modes in Janus Monolayers and Weyl Semimetals”�� 70

GP-MS Session B

Lianming Tong (Peking University)“Circularly Polarized Raman Scattering of Two-Dimensional Materials” ��� 72

GP-MS Session C

Teng Yang (Institute of Metal Research, Chinese Academy of Sciences)“Double Resonant Raman Scattering in TMDCS”����������� 74

Poster Award Ceremony 10:50-11:10
Closing Remarks

11:10 - 11:20
NAGASAKA Tetsuya (Dean, Graduate School of Engineering)����� 76vii

Poster Presentation (Materials Science)
P-1

Manjit Singh Grewal (AIMR)“Innovative Strategies for High-Performance Cross-linked Polymer Electrolytes for
Rechargeable Lithium Ion Batteries” ����������������������� 78

P-2

Jiuhui Han (FRIS / AIMR)“Unveiling the lithium-oxygen electrochemistry by in situ liquid cell transmission
electron microscopy” ������������������������������� 79

P-3

Khuong Kim Huynh (AIMR)“The Large Magnetoresistance in BaMn2Bi2 Antiferromagnet and its Possible Origins”���� 80

P-4

IDZUCHI Hiroshi (AIMR)“Increased Curie Temperature and Enhanced Perpendicular Magneto Anisotropy of
Cr2Ge2Te6/NiO Heterstructures” �������������������������� 81

P-5

KAI Hiroyuki (AIMR)“Space-filling open microfluidics for droplet collection by hierarchical transport:
generative design of fractal hyperbranched channels” ��������������� 82

P-6

Ruma Mandal (AIMR)“Interface-Engineered Magnetic Gilbert Damping: An Experimental and Theoretical
Study in Perpendicularly Magnetized Fe/MgAl2O4 Heterostructures” �������� 83

P-7

SUZUKI Z. Kazuya (AIMR)“Atomic-layered antiferromagnet with perpendicular magnetic anisotropy”����� 84

P-8

YOKO Akira (AIMR)“Turbulent Mixing Phenomenon and Solvent Effects on Kinetics of Supercritical
Hydrothermal Synthesis: Reaction of Nickel Nitrate to Nickel Oxide” �������� 85

P-9

AKAIKE Mizuki (IMR)“Nonreciprocal Electronic Transport in an Itinerant Antiferromagnet PdCrO2 with
120-degree Spin Structure” ���������������������������� 86

P-10

ITO Keita (IMR)“Epitaxial L10-FeNi Films with a High Degree of Order and Uniaxial Magnetic Anisotropy
Fabricated by a Denitriding Method” ����������������������� 87

P-11

Nan Jiang (IMR)“Chirality memory stored in magnetic domain walls in the ferromagnetic state of MnP”��� 88

P-12

KURASHIMA Yutaro (IMR)“Transparent CaHfO3 crystals synthesized by the Core Heating method” ������ 89

P-13

KUROSAWA Shunsuke (IMR)“Study on the bandgap structure for Ce:(La, Gd)2Si2O7 scintillators”��������� 90

P-14

MAEDA Milene Yumi (IMR)“Hydrogen-assisted Damage Evolution in Nitrogen-doped Duplex Stainless Steel”�� 91

P-15

NISHIMURA Hayato (IMR)“ Effects of Residual Stress on Hydrogen Embrittlement of a Stretch-Formed Tempered
Martensitic Steel Sheet”������������������������������ 92

viii

P-16

SATO Mitsutaka (IMR)“Effects of Mn addition on bainitic transformation in Fe-0.3N alloy” �������� 93

P-17

SAWADA Yuya (IMR)“Anomalous Behavior of Magnetization and Magnetic Resonance in the Chiral
Helimagnet” ����������������������������������� 94

P-18

SUDO Kenta (IMR)“Detection of Complete Valley Polarization in Tellurium by Nonreciprocal
Magnetoresistance”�������������������������������� 95

P-19

TAKAGI Rise (IMR)“ Fabrication of 3D micro-patterned metallic glass by imprinting process and application
to Li-ion battery (LIB) electrode” ������������������������� 96

P-20

ISHIGURO Nozomu (IMRAM)“Nano/Meso-scale Chemical State Visualization of Functional Materials Using
Ptychography-XAFS” ������������������������������� 97

P-21

ITO Shunya (IMRAM)“ Organic-Inorganic Hybrid Nanoimprint Replica Molds for Industrial Application”�� 98

P-22

KAMAGATA Kiyoto (IMRAM)“Rational design of peptide targeting intrinsically disordered protein p53 and discovery
of liquid-liquid phase separation of p53”���������������������� 99

P-23

KONDO Yuki (IMRAM)“Analysis of the Effect of Powder Heterogeneity in Compression Molding” ����� 100

P-24

OKAMURA Hidenori (IMRAM)“Stable and orthogonal DNA base pair with translocated recognition units”����� 101

P-25

ONITSUKA Yuuki (IMRAM)“Development of a multi-turn time-of-flight electron analyzer toward molecular orbital
imaging at ultra-high resolution” ������������������������� 102

P-26

Yuxia Zhang (IMRAM)“Cryo-EM structures of SERCA2b reveal the mechanism of regulation by the luminal
extension tail” ���������������������������������� 103

P-27

Zuoqiao Zhu (IMRAM)“Suppression of alkali elution from steelmaking slag for recycling”��������� 104

P-28

AIZAWA Iichiro (Graduate School of Engineering)“Micro-damage detection using backscattering method” �������������� 105

P-29

HAYASHI Kenta (Graduate School of Engineering)“Hydrogen Oxidation Reaction and Hydrogen Peroxide Generation Properties of
Vacuum-Prepared Ru/Ir(111)”��������������������������� 106

P-30

KOIZUMI Ryusuke (Graduate School of Engineering)“Visible-light-induced antibacterial activity of TiO2 layer formed by the two-step thermaloxidation of Ti” ���������������������������������� 107

P-31

MORI Shunsuke (Graduate School of Engineering)“MnTe-based phase change memory with displacive polymorphic transformation”�� 108
ix

P-32

NAKAMURA Jo (Graduate School of Engineering)“Flow Stress Modeling of Alloy 720Li Using Internal State Variables Model”����� 109

P-33

IMAI Taichi (Graduate School of Science)“Thin-Film Properties of BTBT Derivatives withOligo(ethylene oxide) Chains”���� 110

P-34

KUWAHARA Kazuki (Graduate School of Science)“Exosome-targeting probe containing an environment-sensitive fluorophore introduced
into amphipathic helix peptide”�������������������������� 111

P-35

MATSUBAYASHI Yukihiro (Graduate School of Science)“Electronic excitations in high-Tc superconducting cuprates by oxygen K-edge resonant
inelastic X-ray scattering”����������������������������� 112

P-36

NAKAYAMA Kosuke (Graduate School of Science)“High-Resolution ARPES Study on the Origin of High-Temperature Superconductivity in
FeSe1−xTex/CaF2”���������������������������������� 113

P-37

NOJIMA Rinto (Graduate School of Science)“ Electrical resistivity measurements under high pressure for iron-based ladder material
BaFe2(S1−xSex)3” ���������������������������������� 114

P-38

TOMIYOSHI Yoshinori (Graduate School of Science)“Dissipative particle dynamics approach to reaction-induced morphological changes inthermoplastic/thermosetting resin mixtures” ������������������� 115

P-39

Dmytro Demirskyi (AIMR / Graduate School of Engineering)“Solid Solution Strengthening and High-Temperature Strength in TiC–TaC–ZrC–NbC
Ceramics” ������������������������������������ 116

P-40

KISU Kazuaki (AIMR)“Electrochemical characterization of Magnesium Borohydride Ammonia Borane
Mg(BH4)2(NH3BH3)2 as a Magnesium Ionic Conductor” ��������������� 117

P-41

Teng Ma (AIMR)“Two dimensional bio-hybrid membranes based on self-assembly”��������� 118

P-42

OKA Hirofumi (AIMR)“In-situ low-temperature scanning tunneling microscopy and spectroscopy studies ofSrVO3 and Pr thin films”������������������������������ 119

P-43

Fei Sun (AIMR / IMR)
“Phase Separation with Ordering in Aged Fe-Ni-(Al,Mn) Alloys”���������� 120

P-44

Joseph R. Nelson (AIMR / University of Cambridge)“Analysing ion conduction using persistent homology in lithium solid electrolytes”�� 121x

Project Introduction of the Core Research Cluster for Materials Science
P-45

Advanced Energy Materials Project“The Core Research Clusters for Materials Science -Advanced Energy Material-” �� 123

P-46

Advanced Electronic Materials Project“Advanced Electronic Materials Project in Core Research Clusterof Material Science”�������������������������������� 124

P-47

Biomaterials Project“Next-generation medical diagnosis and treatment based on bio-hybrid materials anddevices” ������������������������������������� 125

P-48

Materials Development Based on Microstructure Control Project“Strengthening by metastable solute clustering/precipitation in low-alloy nitrogen steels”
����������������������������������������� 126

P-49

High Strength Materials Project“Overview of the High-Strength Materials Project”����������������� 127

P-50

Mathematical Science and Computation Project“Endothelial Cells Distribution on the Stent Strut with Surface Treatment after the Flow
Exposure” ������������������������������������ 128

P-51

Evaluation and Sensing Project“Evaluation and Sensing Project - support through collaboration between microscopic
analysis, measurements and evaluation infrastructure-” �������������� 129

P-52

Processing Project“Process Science Toward Design and Control of Nanomaterials” ���������� 130

P-53

Education and Human Resources Development Project“Formation of the global human resources development base
- Introduction of International Joint Graduate Program in Materials Science -” ��� 131

P-54

Core Research Cluster for Materials SciencexiPoster Presentations(International Joint Graduate Program in Materials Science)
P-55

BABA Akiko (Graduate School of Science)“Properties of Primitive Membrane and Optimization of Biopolymers
in Life Evolution” ��������������������������������� 133

P-56

CHIBA Toshikaze (Graduate School of Science)“Development of Microfluidic Device for Planar Assembly of Giant Vesicles” ���� 134

P-57

HACHIYA Yuto (Graduate School of Science)“Promotion of DNA Synthesis by Liposome Surface” ���������������� 135

P-58

HATAKEYAMA Takuya (IMR)“Phase stabilities of magnesiated MnO2 polymorphs as cathodes for magnesium
rechargeable batteries” ������������������������������ 136

P-59

Yeon Beom Jeong (IMR)“Effect of Minor alloying elements on Microstructural and mechanical properties
changes in Ti-Fe Alloy” ������������������������������ 137

P-60

KANNARI Koki (Graduate School of Science)“Revealing the Reaction Mechanism of Li-O2 Battery by in-situ Surface-Enhanced Raman
Scattering (SERS)”��������������������������������� 138

P-61

KAWAMORI Hiroaki (Graduate School of Engineering)“High-Pressure Synthesis and Defect Chemistry of Hydrated Ba-Sc-Based Perovskites”
����������������������������������������� 139

P-62

KIMURA Koya (Graduate School of Engineering)“Mixed Conduction and Local Structural Analysis of Y and Al co-doped BaZrO3”��� 140

P-63

KOSABA Takumi (Graduate School of Engineering)“Effect of Anodizing Time on Galvanic Corrosion Resistance on Localized Corrosion
Initiated at IMP of Al Alloys” ��������������������������� 141

P-64

KURISU Minoru (Graduate School of Science)“Giant Vesicle of AOT: New Material for Soft Microscale Compartment and its Dynamic
Property”������������������������������������� 142

P-65

MATSUO Takaya (Graduate School of Science)“Synthesis and n-type thermoelectric application of pyranylidene-substituted
heteroaromatics with extremely high electron-donating ability” ���������� 143

P-66

OGASAWARA Takuma (AIMR)“Title in Bold and Centered is to Appear in 14 pt. Times New Roman Using Initial
Capitals” ������������������������������������� 144

P-67

Chioma Uche Okeke (Graduate School of Science)“Effect of the Alkyl Linker of Thiazole Orange Base Surrogate in the Peptide Nucleic
Acid-DPQ Conjugate on the Binding and Fluorescence Sensing of the Promoter Region of
Influenza A Virus RNA” ������������������������������ 145

xii

P-68

SAITO Haruka (School of Engineering)“Fabrication of Type 304L Stainless Steel Containing Mo-rich Phases By Spark Plasma
Sintering and Its Corrosion Resistance in 0.1 M NaCl” ��������������� 146

P-69

Zheng Shao (School of Engineering)“Elucidation of the Initiation of Pitting Corrosion and the Growth of Filiform Corrosionof AZ91D Die-cast Mg Alloy”���������������������������� 147

P-70

TAKADA Chunji (Graduate School of Science)“Oxidation Mechanism of the Unsaturated Phospholipid Monolayer in the Low-level
Ozone Studied by HD-SFG” ���������������������������� 148

P-71

TAZAWA Toma (Graduate School of Engineering)“Surface oxygen dissociation reaction rates of Co-containing oxides”�������� 149

P-72

UEHARA Hiroki (Graduate School of Engineering)“Local structure and mixed conductivity of Co-doped BaZr0.9Sc0.1O3-δ” �������� 150

P-73

YAMAGUCHI Mina (Graduate School of Engineering)“Black Titanium Oxynitride Thin Films Prepared by Ion-Beam-Assisted Pulsed Laser
Deposition”������������������������������������ 151

P-74

YAMAMOTO Yuki (Graduate School of Science)“Synthesis of anti-ThCr2Si2-type La2O2Bi epitaxial thin film by multilayer solid-phase
epitaxy method” ��������������������������������� 152

xiii

Plenary Session 1

Solute-dislocation binding: understanding the mechanism for room
temperature ductility of Mg alloys
Jong-Kwan Lee1,2, Hyo-Sun Jang1, Antonio João Seco Ferreira Tapia1,2, Nack Joon Kim2
and Byeong-Joo Lee1
1

Department of Material Science and Engineering,
Pohang University of Science and Technology (POSTECH), Republic of Korea
2
Graduate Institute of Ferrous Technology,
Pohang University of Science and Technology (POSTECH), Republic of Korea
Non-basal slips play an important role in overcoming the poor ductility and formability ofmagnesium. We have proposed that alloying elements can activate non-basal slips by
reducing critical resolved shear stress anisotropy among slip systems and that the optimum
content of alloying elements in binary Mg alloys can be estimated, using atomistic
simulations [1,2]. However, the detailed criterion for the activation of <c+a> slips inmulticomponent Mg alloys, which can be utilized in commercial Mg alloys, requires further
understanding. We found that the critical resolved shear stress anisotropy of amulticomponent Mg alloy can be minimized, resulting in an activation of the <c+a> slips, if
the alloy has a dislocation binding intensity equivalent to associated binary Mg alloys
optimized to minimize the critical resolved shear stress anisotropy. We also found that theactivation in multicomponent Mg alloys can be robust when the element with relatively weakdislocation binding is the main alloying element. It was confirmed through an experiment thatthe multicomponent Mg alloys satisfying the above criterion show higher room-temperaturetensile elongation and formability than other alloys.
Further, as a structural material, a reasonable strength is required from Mg alloys and a
precipitation hardening can be an effective way to improve the strength. Important here is thatthe additional alloying for precipitation hardening should not have a harmful effect on the
optimized dislocation binding. A thermodynamic calculation can be utilized to estimate theamount of solute in matrix and precipitates. It will be demonstrated how the thermodynamic
calculation can be combined with the atomistic simulation as a new alloy design technique toimprove the strength without disturbing the well-optimized ductility and formability, together
with an experimental verification.
[1] K.-H. Kim, J.B. Jeon, N.J. Kim, B.-J. Lee, Scripta Mater. 108, 104 (2015).
[2] K.-H. Kim, J.H. Hwang, H.-S. Jang, J.B. Jeon, N.J. Kim, B.-J. Lee, Mater. Sci. Eng. A
715, 266 (2018).

Fig. 1. Formability vs. Strength of various Mg alloys.

5Session 1-A

Electron Theory Calculation of Thermodynamic Properties of Alloys
and Its Application to Theoretical Phase Diagrams
Hiroshi Ohtani 1* and Masanori Enoki 1
1Institute of Multidisciplinary Research for Advanced Materials,
Tohoku University, Sendai 980-8577, Japan

In controlling to maximize the functions of various materials, the role which the
CALPHAD (Calculation of Phase Diagrams) method has played is very large. However, it isvery difficult to apply this technique to the system which has not been clarified inexperiments, metastable regions, and non-equilibrium phases. Then in this study, newapproach to constitute phase diagrams will be proposed for incorporating with such problems.
In order to make a phase diagram of a certain system, the identification of the orderedstructure which constitutes the phase region is most important. Then the ground structures ofthe system were estimated by first-principles calculations based on genetic algorithm, and thefree energies of their structures are evaluated by electronic calculations and statistical
thermodynamic techniques. In addition, the phase diagrams at finite temperature weretheoretically constructed using the calculated free energies, and the result was compared withthe experimental knowledge.
As an example of the calculation results, the theoretical phase diagram for Fe-Mo-B ternary
system at T = 1323 K is shown in Fig. 1(a). For comparisons, calculated phase diagrams by
the authors group using CALPHAD method is shown in Fig. 1(b), together with experimental
values. The space groups and compositions of many ground structures obtained by thecalculations correspond well with the experimental findings, but the agreement is not perfect.
However, by including metastable structures by only a few kJ/mol than the ground state, it
becomes clear that the appearance of almost all structures can be predicted based on thistechnique. The new calculation technique of such theoretical phase diagrams suggested in thepresent study is expected to open up the possibility of estimation of unknown phase diagram,reexamination of experimental phase diagrams and discovery of new phases. On the other
hand, examining the calculation conditions for improving the accuracy of energy calculation,
consideration of the anharmonicity of atomic vibration, magnetic entropy effect, handling ofsolid solution, etc. are mentioned as problems requiring further consideration.

Fig. 1. (a) Theoretical phase diagram for Fe-Mo-B ternary system at T = 1323 K and (b)Calculated phase diagram by thermodynamic analysis with experimental data.

9

Session 1-B

Resource logistics approach on critical resources for future society
Kazuyo Matsubae1* Kenichi Nakajima2 Tetsuya Nagasaka3
1

Graduate School of Environmental Studies, Tohoku University, Japan
2
National Institute of Environmental Studies, Japan
3
Graduate School of Engineering, Tohoku University, Japan

Water intensity (kL/t ore)

There is no doubt that the large-scale development and diffusion of climate change
mitigation technologies is urgently required in our society. On the other hand, the acquisitionof the additional mineral resources required by these technologies is expected to result invarious negative impacts on the global environment. These include the depletion of limited
mineral resources, damage to water bodies, stress on land surface areas, and the creation of
toxic waste products.
Globally, the extraction of metal ores increased by more than 250% from 1970 to 2010.
Copper is second only to iron ore in terms of the volume of metal ore extracted [1]. The recent
increase in the global demand for copper [2] is certain to continue due to infrastructure
maintenance in emerging countries and the increased production of electric vehicles [3].
However, since only a limited number of countries and regions are rich in copper andengaging in domestic copper extraction [4], many countries and regions procure copper
through international trade-based supply chains.
The flow of resources in complex supply chains and the impact of green innovations on thelife cycle of those resources needs to be understood. The importance of “resource logistics”
has been growing in tandem with global concerns about resource and environmental
constraints. Likewise, responsible mining, as a constituent of social responsibility associatedwith resource extraction and usage, is becoming increasingly important.
In this study, the focus was on
800
copper as an indispensable material for
700
climatechangemitigation
Open Pit
technologies. We estimated the600Open Pit/ Undergroundamount of water used during theUnderground500
procurement of copper resources to
400
support economic activities in300
different countries and regions
200(Fig.1)[5]. We also investigated the100
water supply risk for the water needed0
for these activities. The amount of
0.0
1.0
2.0
3.0
4.0
Copper grade (%Cu)
water used in domestic copper mine
production and that generated by
Fig.1 Water intensity against copper ore grade
copper ore imports was clarified.
[1] United Nations Environmental Programme, International Resource Panel (UNEP IRP),(2016) http://www.resourcepanel.org/file/423/download?token=Av9xJsGS[2] K. Nakajima, I. Daigo, K. Nansai, K Matsubae, W. Takayanagi, M. Tomita, Y. Mastuno,
Resour. Conserv. Recycl. 133, 369–374. (2018)[3] F. Un-Noor, S. Padmanaban, L. Mihet-Popa, M.N. Mollah, E.A. Hossain, Energies, 10,1217 (2017)[4] United States Geological Survey (USGS), Minerals Yearbook, copper, (2015),
https://minerals.usgs.gov/minerals/pubs/commodity/copper/myb1-2015-coppe.pdf[5] A. Oashi, K, Matsubae, K. Nakajima, T. Nagasaka, Proceedings of Institute of Life Cycle
Assessment, B2-03 (2018)11

Session 1-C

Kink Strengthening of Mille-feuille Structures in Mg Alloys
Eiji Abe
Department of Materials Science and Engineering, University of Tokyo,
7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, JAPAN
Dilute Mg alloys containing a few atomic percent of transition-metal and rare-earth
element have attracted increasing attentions because of their excellent mechanical properties[1]. The remarkable microstructural feature common for all of these Mg alloys is formation of
a novel type of long-period stacking/order (LPSO) structures [2,3], which reveal a remarkable
strength through the warm-extrusion process. During the process the LPSO crystals are
deformed not by simple dislocation migrations but kink formations (Fig. 1) that are the direct
relevance to realize excellent properties of the alloys. From the extensive studies of the
LPSO-structured Mg alloys for more than the past two decades, it has become apparent thatthe kink regions indeed provide an extra strengthening effect [4] for the alloys, but its detailed
mechanism is not fully understood yet.
In order to deepen our understanding of the veiled work-hardening mechanism
related to kink, we have launched the new project aiming the establishment of the “Kinkstrengthening phenomenon” as a universal strengthen principle [5]. In the meantime, the
LPSO structure can be generally viewed as “Mille-feuille structure (MFS)”, in the sense thatthey are constructed by alternate stacking of microscopic hard- and soft-layer. That is,regarding LPSO-forming Mg alloys, the isolated structural unit is found to be highly stableeven when distributed sparsely/randomly to form MFS [6]. Our recent studies have confirmedthat the MFS-Mg alloys indeed reveal the kink strengthening, whose effect seems to be more
prominent than LPSO Mg alloys. Therefore, solving the critical condition and universality on
the kink-strengthening phenomenon will certainly lead to a further development oflightweight structural materials, including novel Al and Ti alloys, and even polymer materials
in the future.
[1] Y. Kawamura, K. Hayashi, A. Inoue, and T. Masumoto, Mater. Trans. 42 (2001) 1172.
[2] E. Abe, Y. Kawamura, K. Hayashi, and A. Inoue, Acta Mater. 50 (2002) 3845.
[3] D. Egusa, and E. Abe, Acta Mater. 60 (2012) 166.
[4] K. Hagihara, M. Yamasaki, Y. Kawamura, and T. Nakano, Acta Mater. 163 (2019) 226.
[5] https://www.mfs-materials.jp/en/[6] M. Egami, I. Ohnuma, M. Enoki, H. Ohtani, and E. Abe, Materials and Design 188 (2020)

Fig. 1. HAADF-STEM image of kink-deformed MFS regions in a MgZn1Y2 alloy

13

Session 2-A

Development of γ′-strengthened Co-base superalloys
with improved comprehensive performances

1

Qiang Feng 1, Longfei Li 1, Wendao Li 1, Zou Min 1, Xiaoli Zhuang 1
Beijing Advanced Innovation Center for Materials Genome Engineering,
State Key Laboratory for Advanced Metals and Materials,
University of Science and Technology Beijing, Beijing 100083, China

In 2006, Sato and Ishida et al. in Tohuku University discovered the novel γ′-strengthened
Co-Al-W-base alloys, which show potential for improved mechanical properties at hightemperature than conventional Co-base alloys, opening up a new path for the development of
Co-base superalloys. Since then, worldwide efforts have been made to improve thecomprehensive performance of this new type of materials.
In the last decade, our group have done a plenty of investigations on the alloying effects of
Ta, Ti, Nb, Mo and V on the γ′ solvus temperature, γ/γ′ two-phase stability and precipitationof secondary phases of Co-Al-W-base alloys, through the traditional "trial and error" method.
A Co-Al-W-Ta-Ti quinary single crystal alloy was designed which demonstrates good hightemperature γ/γ′ microstructural stability and excellent creep property, owning to theinteraction effect of Ta and Ti. However, such quinary single crystal alloy is not suitable forengineering application, due to the narrow γ/γ′ two-phase region, higher alloy density and theabsence of alloying elements for environmental resistance.
In recent years, an accelerated methodology integrating CALPHAD, diffusion-multiple
approach and machine learning method is developed in our group to systematicallyunderstand the alloying effects of different elements, i.e. Ni, Al, W, Ti, Ta, Ni, Mo, on themulticomponent γ′-strengthened Co-base alloys, by which the Co-based superalloys with wellbalance of long-term microstructural stability, strength and oxidation resistance could be
developed for different service purposes, such as turbine blades and disks. This work will bevery helpful for the future alloy design efficiently.
[1] J. Sato, T. Omori, K. Oikawa, I. Ohnuma, R. Karinuma, K. Ishida, Cobalt-basehigh-temperature alloys, Science 312, 90-91 (2006).
[2] J.-C. Zhao, Combinatorial approaches as effective tools in the study of phase diagrams andcomposition–structure–property relationships, Prog. Mater. Sci. 51, 557-631 (2006).

Fig. 1. Research Road Map of novel γ′ strengthened
Co-base alloys.

17

Session 2-B

Characterization of Dislocation Motions in Metallic Materials by
TEM In-situ Straining and Nanoindentation
Takahito Ohmura1, 2, 3*, Seiichiro. Ii1 and Hongxing. Li1
1

2

National Institute for Materials Science, Tsukuba
Course of Advanced Nanomaterials Science and Engineering, Kyushu University, Fukuoka
3
Elements Strategy Initiative for Structural Materials, Kyoto University, Kyoto

Local deformation behavior in metallic materials governs macroscopic properties andinvolves dislocation motion deeply. One can elucidate the fundamental mechanisms of the
microstructure-properties relation through great potential approaches including dynamic
observation of the dislocation glide by TEM in-situ straining and probing the local
mechanical response through nanoindentation under an applied stress.
Load-displacement curves by nanoindentation clearly show the plasticity initiation and thesubsequent deformation in “pop-in” behavior on the loading segment. Fig. 1 shows
probability distributions of magnitudes in the first pop-in and the subsequent one as a functionof the stress drop  for a single crystal Fe with (001) surface orientation [1]. The first event,which is a transition from pure elastic strain to an elastoplastic deformation, shows Gaussian
like distribution, indicating a thermally-activated process of dislocation nucleation at
defect-free region in the material. On the other hand, the second and subsequent events follow
a power-law function like Gutenberg-Richter model in seismology, suggesting a dislocation
avalanche as a catastrophe phenomenon.
Dynamic interactions between lattice dislocation and grain boundaries can be captured by
TEM in-situ straining. In the case of 3 coincidence site lattice grain boundary in pure Al
bicrystal, the slip transfer goes through the boundary with a dislocation reaction there [2]. The<110> lattice dislocation dissociates into a grain boundary dislocation and another <110>lattice dislocation in the adjacent grain. Since the dislocation self energy is proportional to asquare of a magnitude of the Burgers vector and is exactly the same for the <110> lattice
dislocations in the original and the adjacent grains, the energy barrier for the slip transfer
corresponds to the formation of the grain boundary dislocation. In the early stage of
deformation below the yield stress in an ultra-fine-grained (UFG) steel, dislocations in graininterior move forward to a grain boundary and then are absorbed there with no pilling up.
Dislocation density in the grain interior
decreases with increasing strain, which isconsistent with a case in a macroscopic tensile
specimen, therefore the extra hardening inHall-Petch plot in the UFG steel can be
attributed to a starvation of the mobile
dislocation based on a combination of Orowan
model and Johnston-Gilman theory.
[1] Y. Sato, S. Shinzato, T. Ohmura, T.
Hatano, S. Ogata, Nature Comm., 11,4177 (2020).
[2] S. Ii, T. Enami, T. Ohmura, S. Tsurekawa,submitted.
[3] H. Li, S. Gao, Y. Tomota, S. Ii, N. Tsuji,
T. Ohmura, submitted.

19

Fig. 1. Probability distributions of first
pop-in and subsequent one
magnitudes as a function of thestress drop for Fe [1].

Session 2-C

Challenges of composite powder fabrication for additive manufacturing
NOMURA Naoyuki* and ZHOU Weiwei
Department of Materials Processing, Graduate School of Engineering, Tohoku University,
6-6-02, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan
Additive manufacturing (AM) has attracted much attention as a new method for creatingparts with complicated shape. The consumer side sometimes calls the method 3-D printing,and the technical innovation is rapidly going forward during the last decades especially forhigh -power heat source, large build fabrication, process monitoring, and so on. In thisprocess, the 3-D CAD data is sliced to provide the AM machine and the laser or electron
beam are scanned on the powder according to the data. The irradiated powder is melted andconsolidated with the cross-section shape. The powder is recoated depending on the required
resolution thickness and is scanned again according to the next layer data. This process isperformed repeatedly until the parts are obtained. This method can from complicated shapeswith internal structure impossible by traditional fabrication method. Thus, AM can realize theparts with innovative design. Steels, Ni, Ti, and Al alloys powders are already provided for
AM, and the variety of metal powders applicable to AM is increasing as the application fields
are expanding such as medical implants, molds for plastics, and aerospace.
In our research group, we are now focusing on the fabrication of composite powders(Fig. 1) to develop additively manufactured composites having superior properties to the AM
metallic builds. In this presentation, several composite powders developed by our group andthe AM builds showing characteristic microstructures will be introduced [1-3].
[1] W. Zhou, X. Sun, K. Kikuchi, N. Nomura, K. Yoshimi, and A. Kawasaki, Mater. Des.,
137, 276-285 (2018).
[2] W. Zhou, K. Kikuchi, N. Nomura, K. Yoshimi, and A. Kawasaki, J. Alloy Comp., 819,
152981 (2020).
[3] N. Nomura, W. Zhou, Z. Zhou, and K. Yoshimi, Ceramics Japan, 55, 90-92 (2020).

cFig. 1. Schematics and SEM image of a NiAlCrMo/ATCNT/Al2O3 composite powder[1] (reuse with the permission of Elsevier).

21

Student Session 1-A

High-throughput Characterization Methods for Corrosion Research
Ying JIN, Zhaogui LAI, Yang ZOU, Chaoyang ZHAONational Center for Materials Service Safety, University of Science and Technology Beijing,
Beijing 100083, China
Corrosion assessment is a pivotal step in the development of new inhibitors, coatings, andanti-corrosion alloys. In order to improve the low-efficiency of traditional techniques forelectrochemical characterization, the high-throughput theory and methodology have been
proposed to address this issue in the past two decades. This lecture is to present examples toillustrate this possibility, in which two material libraries were selected to demonstrate theapplication of high throughput multi-analytical techniques in material comprehensive
evaluation, one is an artificial Fe-Cr-Ni thin film specimen, the other is a natural
308L-309L/SA508 weld joint specimen.
The demonstrated high throughput study involved multi-analytical techniques. Electronprobe X-ray microanalysis (EPMA) and X-ray diffraction (XRD) of synchrotron radiation
source were used to characterize composition and microstructure, respectively.
Metallographic observations were conducted by scanning electronic microscope (SEM) andautomatic photographing optical microscope (OM). Scanning Kelvin probe (SKP) or scanning
Kelvin force microscopy (SKPFM) was utilized to evaluate the nobility of the specimens withdifferent compositions. In addition, the electrochemical properties were characterized by aself-assembled high-throughput local electrochemical test apparatus.
Moreover, high-throughput data analysis techniques were also developed and utilized toaccomplish data processing more effectively and intelligently. For instance, hierarchy
clustering was implemented to categorize the thousands of X-ray diffraction patterns.
Multiple machine learning (ML) classification algorithms were adopted to predict thecorresponding equvilent circuit model (ECM) of a bunch of electrochemical impedance
spectroscopy (EIS), and employed various meta-heuristic global optimization algorithms toautomatically fit the parameters of ECM. As a result, the relationship between
composition-structure-property could be extracted through data mining.

23

Student Session 1-B

Calcium Phosphate Coating of Mg/Mg alloys for Biomedical Use
Sachiko Hiromoto1*
1

National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047

Magnesium/Mg alloys are starting to be practically used for biodegradable medical devices
such as bone screws and stents. The initial rapid corrosion of Mg/Mg alloys reduces thestrength and the generated H2 gas forms cavities which can prevent the surrounding tissue toadhere to the material surface. The corrosion control of Mg/Mg alloys is thus a crucial issue.
We developed hydroxyapatite (HAp) and octacalcium phosphate (OCP) coatings [1] and thecoatings retarded the corrosion speed of Mg/Mg alloy in a cell culture medium and in mouse
subcutaneous tissue [2,3]. The HAp coating retarded the initial corrosion of Mg/Mg alloys in
rat femurs and enhanced the bone formation [4]. In this presentation, the formation of the
HAp coatings and the corrosion behavior of HAp-coated Mg/Mg alloys in various
environments will be introduced.
As a substrate, Mg-3mass% Al-1mass% Zn (AZ31) discs were used for the immersion test
in a cell culture medium and the implantation test in mouse subcutaneous tissue. Pure Mg
rods were used for the implantation test in rat femurs. HAp coatings were formed on thesubstrates by immersing in a previously reported solution [2] at 90℃ for 1~2 hours.
Figure 1 shows SEM images of HAp-coated and uncoated Mg/Mg alloy
immersed/implanted in various environments. The corrosion layer of the HAp-coated Mg/Mg
alloy was thinner than that of the uncoated specimens in medium and soft and hard tissues. It
was demonstrated that the HAp coating is effective to retard Mg corrosion in vitro and invivo.
In medium, corrosion progressed homogeneously under the HAp layer (Fig. 1(b)); whereas
in soft and hard tissues, localized corrosion was observed under the HAp layers (Fig. 1(c, e)).
In gelatin-added medium, in which mass transfer was restricted, HAp-AZ31 showed localized
corrosion under the HAp layer (Fig. 1(d)). Corrosion product in medium partly dissolved
while that in soft tissue mostly undissolved (Fig. 1(f, g)). The localized corrosion under the
HAp layers in soft and hard tissues indicates that the low diffusivity and relatively smallliquid content of tissues allowed body fluid to permeate preferentially through the defects of
HAp layers. It is suggested that the mass diffusivity and liquid content in the surrounding
tissues influences the corrosion behavior of HAp-coated Mg/Mg alloys.
[1] S. Hiromoto et al., Electrochim. Acta. 54, 7085-7093 (2009). [2] S. Hiromoto, M. Inoue,
T. Taguchi, M. Yamane, N. Ohtsu, Acta Biomater. 11, 520-530 (2015). [3] S. Hiromoto,
Corros. Sci. 100, 284-294 (2015).[4] S. Hiromoto, E. Nozoe, K. Hanada, T. Yoshimura, K.
Shima, T. Kibe, N. Nakamura, K. Doi (submitted).

Fig. 1 Cross-section SEM images of (a-d) HAp-AZ31 and (f,g) uncoated AZ31 (a) as-prepared, (b, f) immersed
in medium for 52 weeks, (c,g) implanted in mouse subcutaneous tissue for 16 weeks and (d) immersed ingelatin-added medium for 4 weeks and (e) HAp-Mg and (h) uncoated Mg implanted in rat femur for 4 weeks.

25

Student Session 1-C

Effect of Anodizing on Galvanic Corrosion Prevention ofPure aluminum Coupled to Pure iron and stainless steel
Takumi Kosaba1*, Izumi Muto1 and Yu Sugawara1
1

Department of Materials Science, Tohoku University

Due to the prevention of global warming, the demand for weight reduction of automobiles
is increasing these days: then the multimaterial structures, which is one of the methods toachieve the weight reduction, attract great interest. Because of low cost and high stiffness,aluminum alloys and steels joints are anticipated to utilize in the structures. However,galvanic corrosion is expected to occur on less noble potential metals such as aluminumalloys.
The evaluation of galvanic corrosion has been generally performed by corrosion potential
difference; therefore, the active dissolution of aluminum alloys is accelerated because theelectrode potential of aluminum alloys increased by the coupling. In the case of the galvanic
corrosion in chloride solutions at near-neutral pH, the anodic reaction on aluminum alloys areoxide film formation and/or localized corrosion generation like pitting. For pure aluminum
and aluminum alloys, the generation of localized corrosion is generally evaluated by thecritical potential for localized corrosion, such as pitting potential. Consequently, in chloride
solutions at near-neutral pH, galvanic corrosion should be evaluated by comparison between
electrode potential of aluminum alloys under coupling and the critical potential for localized
corrosion.
To prevent the galvanic corrosion, inhibitor and surface modification have been adapted tothese joints. Among these techniques, anodizing is expected to be effective as the surface
modification techniques because thicker anodic oxide film contributed to improvement on
corrosion resistance of aluminum alloys; however, there is little research related to theimprovement on galvanic corrosion resistance of aluminum alloys under coupling with steels
by anodizing.
In this research, we investigated the galvanic corrosion behavior of pure aluminum coupled
to pure iron in diluted synthetic seawater. This electrolyte simulated the chloride solutions at
near-neutral pH relevant to atmospheric environments. The galvanic corrosion tests werecarried out by zero resistance ammeter techniques. Moreover, the galvanic corrosion behaviorof anodized aluminum coupled to pure iron or Type 430 stainless steel was studied. Purealuminum surface was modified by anodizing in sulfuric acid at various anodizing voltage andtime conditions. we performed the galvanic corrosion tests between anodized aluminum andpure iron or Type 430 stainless steel in diluted synthetic seawater, and the thickness of anodic
oxide film to prevent galvanic corrosion damage on anodized aluminum was determined.

26

Session 3-A

Future of High Value Manufacturing(Introduction of Bio-Medical Applications for the Super Aging Society)
Tsunemoto Kuriyagawa
Tohoku University, 6-6-01 Aramaki Aoba, Aoba-ku, Sendai 980-8579
We aim to promote innovations of pico- & nano-precision Micro/Meso Mechanical
Manufacturing (M4 process) at the frontier of manufacturing technology, including
ultra-precision mechanical manufacturing technologies for various shapes, nano-precision
fabrication for 3D microstructures, atom/molecule manipulation for nanostructures and so on.
Our goal is not only to create high-precision shapes, but also to generate functional structureson the shape by controlling the micro textures. Today, I will introduce an unique technology,
which is powder jet deposition (PJD). The deposition mechanism of PJD was studied withsmoothed particle hydrodynamics (SPH) and molecule dynamics (MD) simulations. The
deformation of a particle and a substrate by impact was successfully simulated. From theresult, a thick film is generated due to the repetition of the deposition of the stagnation areas.
The blasting experiments were also conducted to study the machining mechanism at transition
condition. The machining surface was analyzed with SEM and TEM. It was that found fromthese results, the removal process of the substrate material and deposition process of particles
onto the substrate occur concurrently under the transition conditions. Utilizing the PJD, ahydroxyapatite film has been successfully deposited on a human tooth as a new dental
treatment.
[1] M. Mizutani, C. Kuji, H. Ohisa, S. Nishimura, K. Mizutani, R. Akatsuka, K. Sasaki, S.
Xu, K. Shimada, and T. Kuriyagawa, Particle fracture behavior and deposition
mechanism in powder jet deposition (PJD), J. of JSAT, 61 (1), 28-33 (2017).

H A p f ilm

HA film

Same
Vickers hardness
as enamelenamelenamelprism

× 1.5 k 25
kv

20 um

Fig. 1. Developed dental PJD unit and deposited HA film on human enamel.

29Session 3-B

Protein-based molecular evolution for nano-bioengineering
Mitsuo Umetsu1,2
1Department of Biomolecular Engineering, Graduate School of Engineering,Tohoku University
2
Center of Advanced Intelligence Project, RIKEN, Japan

Protein is a biopolymer where the amino acids with various side chain are dehydrated, andthe sequence of amino acids are coded by DNA. The variety of the amino acid sequences,called sequence space, is so huge that a diversity of function can be expressed. The design ofamino acid sequence lead directly to a creation of functional protein, but no reliable rationalsequence design has been established. Molecular evolution is widely used in protein
engineering, where a library of protein variants by means of mutagenesis on a scaffold protein
and the variants with a specific function are survived in the selection process. However, themassive scale of sequence space makes it tough to explore a goal variant, because preparing
the library with the goal variants and screening the variants from the library are low
probability. In this background, we study the “library design cycle”, where a local area with agoal variants in sequence space is identified at first step by mean of wet techniques,bioinformatics, and AI , and we explore the goal variants in the designed local library. With
this methodology, we are creating various available recombinant proteins in the therapeutic,
diagnostic, environmental, and material fields. Here, I show several attractive proteins fornanobiotechnology and therapeutic fields, by means of our powerful approach for accelerated
discovery of functional proteins.
[1] T. Niide, N. Manabe, H. Nakazawa, K. Akagi, T. Hattori, I. Kumagai, and M. Umetsu,
Langmuir, 35, 3067−3076 (2019).
[2] Y. Saito, M. Oikawa, H. Nakazawa, T. Niide, T. Kameda, K. Tsuda, and M. Umetsu, ACS
Synthetic Biology, 7, 2014–2022 (2018).
[2] H. Fujii, Y. Tanaka, H. Nakazawa, A. Sugiyama, N. Manabe, A. Shinoda, N. Shimizu, T.
Hattori, K. Hosokawa, T. Sujino, T. Ito, T. Niide, R. Asano, I. Kumagai, and M. Umetsu,
Advanced Therapeutics, 1700031 (2018).
[3] H. Nakazawa, D.-M. Kim, T. Matsuyama, N. Ishida, A. Ikeuchi, Y. Ishigaki, I. Kumagai,
and M. Umetsu, ACS Catalysis, 3, 1342-1348 (2013).
Smart Nano-Bio Design
Nano
Dry

Bioinformatics

Deep learning
Evolutionengineering

Molecular
dynamics

AI

Bio

HybridCentral dogma

Small-molecule drug
Tumor model

Giant Gene

High-throughput
screening

Wet

siRNA

Nanoparticle

Cell manipulation
DNA

RNA

Protein

Medicine Environment

Material

Biosensor
CancerBiomineralization Bottom up design
KidneyBioenergy
Infection

Fig. 1. Smart nano-bio design for the medical, environmental, and material fields

31

Session 3-C

Electrochemistry Confined Nanopore: Design and Application in Single
Molecule Sensing
Yi-Tao Long

School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R.
China, E-mail: yitaolong@nju.edu.cn
The single molecule measurement has enhanced the precision and depth of our knowledge
about living system. Learning from nature, the million years of evolution have produced themembrane proteins which acts as a single biomolecule interface for capturing and identifying
a single molecule of interests, and makes biological process occurring. Here, we focus on the
biological nanopore-based single biomolecule interface for single molecule measurements.1-3
We outline the design of nanopore-based single biomolecule interface which provides richheterogeneities and stochastics information about each molecule. Then, we focus on the futureareas beyond DNA sequencing including detecting rare species, resolving the hidden
intermediates, depicting the spectra for the covalent/non-covalent interactions, tracing the
dynamic pathways of single molecule behaviors.4-6 A concept “single-molecule ionicspectrum”, which is considered as “a special music of molecule”, may potentially map the
non-covalent interaction at atomic level in future. Since the characteristic interaction
determines the sensitivity of nanopore, ideally the frequency analysis of nanopore data could
be used not only for DNA sequencing, RNA sequencing, protein sequencing but also all kindsof single molecule detection. As ideally transferring the frequency-energy spectrum from theionic current into the voice frequency, we illustrate that a nanopore-based single-biomoleculeinterface likes a tuba. When a single analyte flows into the ‘tuba’, its dynamic interaction withthe pore could be modulated by the residue of the pore (‘button’) and the resonance space atthe single-molecule interface (‘tuba’). As a result, the incredible music of a single molecule
will be played with a typical rhythm and melody.
1. Y. L. Ying, C. Chao, Y. X. Hu. Y. T. Long, Natl. Sci. Rev., 5, 450-520 (2018).
2. Y. Q. Wang, C. Cao, Y.-L. Ying, S. Li, M. B. Wang, J. Huang, Y. T. Long, ACS Sens., 3,779-783 (2018).
3. Y. Q. Wang, M.-Y. Li, H. Qiu, C. Cao, M.-B. Wang, X. Y. Wu, J. Huang, Y. L. Ying, Y.
T. Long, Anal. Chem., 90, 7790-7794, (2018).
4. C. Cao, Y. L. Ying, Z. L. Hu, D. F. Liao, H. Tian, Y. T. Long, Nat. Nanotechnol., 11,713-716 (2016).
5. C. Cao, Y T Long, Acc. Chem. Res. 51, 331-341 (2018).
6. Y. L. Ying, Y. T. Long. J. Am. Chem. Soc., 141, 15720-15729 (2019).

Figure. A self-assembled aerolysin membrane protein exampled as single
biomolecule interface. The oligonucleotide is taken as an example for illustrating theanalyte.

33

Plenary Session 2

Interplay of Chemistry and Structure at Lattice Defects studied at theAtomic Scale
Dierk Raabe
Max-Planck-Institut für Eisenforschung,
Max-Planck-Str. 1, 40237 Düsseldorf, Germany
Lattice defects like interfaces, stacking faults and dislocations determine many mechanical,
functional and kinetic properties of materials. Lattice defects do not merely constitutestructural imperfections but they are often chemically decorated by solutes as described by the
Gibbs isotherm 100 years ago. The interplay of structure and chemistry at lattice defects canlead to a wide range of phenomena and manipulation opportunities including Suzuki and
Cottrell effects, confined elemental partitioning, linear and planar phase-like states,
decomposition and low-dimensional transformations. All these effects alter the defects’energy, mobility, structure, cohesion and transport properties.
The lecture presents and discusses several aspects in that context:
First, recent progress is presented which allows imaging of both structure and composition
features at lattice defects by using correlative imaging through field ion microscopy, atom
probe tomography and electron microscopy [1,2]. Some of these observation methods areenhanced by using quantum mechanical simulations and machine learning.
Second, atomic-scale experiments on several material classes ranging from metals tothermoelectrics are presented which reveal that the interplay between defect structure andchemistry can lead to a much larger variety in compositional – structural states thancommonly assumed. Examples are confined phase formation, athermal transformations,spinodal decomposition or inter-defect partitioning at lattice defects to name but a few
phenomena, Fig. 1.
Third, some thermodynamic considerations are discussed which may guide better
understanding and utilization of these phenomena.
[1] M. Kuzmina, M. Herbig, D. Ponge, S. Sandlöbes, D. Raabe, Linear Complexions:
Confined Chemical and Structural States at Dislocations. Science 349, 6252 (2015).
[2] D. Raabe, M. Herbig, S. Sandlöbes, Y. Li, D. Tytko, M. Kuzmina, D. Ponge, P. Choi,
Grain Boundary Segregation Engineering in Metallic Alloys: A Pathway to the Design ofInterfaces. Current Opinion in Solid State and Materials Science 18, 253 (2014).

Fig. 1. Interface decoration in AlCuZn
35

Plenary Session 3

Model Systems for Heterogeneous Catalysts at the Atomic Scale
Hans-Joachim FreundFritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
We have created model systems for heterogeneous catalysts on the basis of thin oxide
films. This permits us to apply the toolbox of surface science for characterization and reaction
studies at the atomic scale. Two case studies to demonstrate how those systems may bestudied at the atomic scale are reported.
The first one discusses a novel characterization technique, namely surface action
spectroscopy, using concepts developed in gas phase studies to record vibrational spectra ofextremely dilute specimen based on messenger desorption[1-3]. We demonstrate the extreme
surface sensitivity of this technique by applying it to surface states of oxide surfaces, i.e.
vanadia as well as iron oxides.
The second case study deals with a reaction in confined space using a model system basedon a thin silica film, which is only bound to a metal substrate by dispersive forces, leaving aspace between the oxide film and the metal substrate[4,5]. Here we study water formationfrom intercalated oxygen, adsorbed on the metal surface and hydrogen provided from the gas
phase in operando, and deduce the details of the kinetics of the reaction in confined space indirect comparison to the equivalent open space reaction. To this end we use aspectro-microscope, operated at BESSYII and developed in the group, which allows toobserve tempo-spatial distribution of reactants and deduce apparent activation energies. Thoseexperimental observations are interpreted on the basis of DFT calculations and kinetic
models.
References:[1] Z. Wu, A. Płucienik, F.E. Feiten, M. Naschitzki, W. Wachsmann, S. Gewinner, W. Schöllkopf, V.
Staemmler, H. Kuhlenbeck, and H.-J. Freund, Phys. Rev. Lett. 119, 136101 (2017).
[2] Z. Wu, A. Plucienik, Y. Liu, M. Naschitzki, W. Wachsmann, S. Gewinner, W. Schöllkopf, H.
Kuhlenbeck, and H.-J. Freund, Rev. Sci. Instrum. 89, 083107 (2018).
[3] Y. Liu, Z. Wu, M. Naschitzki, S. Gewinner, W. Schöllkopf, X. Li, J. Paier, J. Sauer, H.
Kuhlenbeck, and H.-J. Freund, J. Am. Chem. Soc. 142, 2665 (2020).
[4] M.J. Prieto, H.W. Klemm, F. Xiong, D.M. Gottlob, D. Menzel, T. Schmidt, and H.J. Freund,Angew. Chem. Int. Ed. 57, 8749 (2018).
[5] H.W. Klemm, M.J. Prieto, F. Xiong, G.B. Hassine, M. Heyde, D. Menzel, M. Sierka, T. Schmidt,
and H.-J. Freund, Angew. Chem. Int. Ed. 59, 10587 (2020).

39

Session 4-A

Nanostructured magnetic materials for thermoelectric generation
Masaki Mizuguchi
Graduate School of Engineering, Nagoya University
The correlation between spin and charge in electronic transports has been energeticallystudied in a scheme of spintronics research. Recently, the coupling between heat current, spincurrent and charge current is also attracting much attention, and this newly established filed iscalled “spin caloritronics”. The recent discovery of the spin Seebeck effect has explosively
expanded this field, and various thermomagnetic effects related to spin current have been
investigated. The Nernst effect is a common thermomagnetic effect, which has been known
for a long time. When a temperature gradient is applied on a material with spontaneous
magnetization, an electric field is induced in the perpendicular direction to both thetemperature gradient and the magnetization, which is called the anomalous Nernst effect(ANE). We have reported ANE measurements of an L10-ordered epitaxial FePt thin film,
which is a well-known material with a large spin-orbit coupling, for studying thermomagnetic
effects in ordered alloys [1, 2]. We also studied the material dependence of ANE regarding thespin-orbit interaction in several perpendicularly magnetized ordered-alloy thin films [3].
Obtaining materials with a large ANE is indispensable to realize a practical application ofANE-based energy conversion. From this point of view, this talk describes our study on the
ANE in various nanostructured materials. A novel material with the strong anisotropy in ANE,
the enhancement of ANE for granular thin films, and spin caloritronic devices with magnetic
nanostructures for ANE-based thermoelectric generation will be discussed [4-7].
The author thanks Mr. Hasegawa, Dr. Takanashi, Dr. Isogami, Dr. Sheng, Dr. Sharma, Dr.
Ohe for their supports in experimental and theoretical studies. This research was partly
supported by JST-CREST (JPMJCR1524), a Grant-in-Aid for Scientific Research (A)(17H01052) from Japan Society for the Promotion of Science, the Center for Spintronics
Research Network (CSRN), and Collaborative Research Center on Energy Materials(E-IMR).
[1] M. Mizuguchi, S. Ohata, K. Hasegawa, K. Uchida, E. Saitoh, and K. Takanashi, Appl.
Phys. Express 5, 093002 (2012).
[2] Y. Sakuraba, K. Hasegawa, M. Mizuguchi, T. Kubota, S. Mizukami, T. Miyazaki, and K.
Takanashi, Appl. Phys. Express 6, 033003 (2013).
[3] K. Hasegawa, M. Mizuguchi, Y. Sakuraba, T. Kamada, T. Kojima, T. Kubota, S.
Mizukami, T. Miyazaki, and K. Takanashi, Appl. Phys. Lett. 106, 252405 (2015).
[4] S. Isogami, K. Takanashi, and M. Mizuguchi, Appl. Phys. Express 10, 073005 (2017).
[5] M. Mizuguchi and S. Nakatsuji, Sci. Tech. Adv. Mater 20, 262 (2019).
[6] H. Sharma, Z. Wen, K. Takanashi, and M. Mizuguchi, Jpn. J. Appl. Phys. 58, SBBI03(2019).
[7] P. Sheng, T. Fujita, and M. Mizuguchi, Appl. Phys. Lett. 116, 142403 (2020).

41

Session 4-B

Search for Superconductivity of Super-hydrides
Synthesized under Extreme Condition
EINAGA Mari1*, SAKATA Masafumi2 NAKAO Harushige1 and SHIMIZU Katsuya1
1

KYOKUGEN, Osaka University, Machikaneyamacho 1-3, Toyonaka, Osaka 560-8531,
Japan
2
Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu city, Gifu, 501-1193, Japan
3
JASRI, 1-1-1, Sayo-cho, Sayo-gun, Hyogo 679-5198.
At the end of 2014, a joint theoretical and experimental investigation broke the record forthe superconducting critical temperature Tc by more than 30 K, reaching 203 K for hydrogensulfide H2S under a high pressure of 150 GPa which was the first increase in 20 years [1, 2].
After this discovery, several theoretical groups proposed the crystal structures and the valueof Tc in a lot of binary and some ternary hydrides. However, only a few experimental works
on the investigation of the way of synthesis and the transport properties of the predicted
hydrides have been reported so far.
Most recently, direct synthesis of several hydrides, for instance, H3S, LaH10, PrH9, ThH7
made from the mixture of the elements (sulfur, lanthanum, praseodymium and thorium), andH2 or hydrogen source has been reported from several groups [3-6]. Especially, lanthanum
hydride shows the highest-Tc ~ 250 K with zero electrical resistance at 170 GPa [3].
Here we report our recent results of synchrotron x-ray diffraction with electrical resistancemeasurements to search for superconductivity of sulfur and lanthanum super-hydrides
synthesized under high pressure and high temperature from sulfur and lanthanumsuper-hydride synthesized from H2S or sulfur and hydrogen, or lanthanum and aluminium
trihydride as the hydrogen source [7-9].
[1] A. P. Drozdov, M. I. Eremets, I. A. Troyan, V. Ksenofontov and S. I. Shylin, Nature 525,
73-76 (2015).
[2] Y. Li, J. Hao, H. Liu, Y. Li, and Y. Ma, J. Chem. Phys., 140, 174712 (2014).
[3] A. P. Drozdov, P. P. Kong, V. S. Minkov, S. P. Besedin, M. A. Kuzovnikov, S. Mozaffari,
L. Balicas, F. F. Balakirev, D. E. Graf, V. B. Prakapenka, E. Greenberg, D. A. Knyazev,
M. Tkacz and M. I. Eremets, Nature, 569, 528–531 (2019).
[4] M. Somayazulu, M. Ahart, A. K. Mishra, Z. M. Geballe, M. Baldini, Y. Meng, V. V.
Struzhkin, and R. J. Hemley, Phys. Rev. Lett. 122, 027001(2019).
[5] D. V. Semenok, A. G. Kvashnin, A. G. Ivanova, V. Svitlyk, V. Y. Fominski, A. V.
Sadakov, O. A. Sobolevskiy, V. M. Pudalov, I. A.Troyan and A. R.Ogano: Materials
today 33, 36 (2020).
[6] D. Zhou, D. V. Semenok, D. Duan, H. Xie, W. Chen, X. Huang, X. Li: Sci. Adv. 6,
eaax6849 (2020).
[7] M. Einaga, M. Sakata, T. Ishikawa, K. Shimizu, M. I. Eremets, A. P. Drozdov, I. A.
Troyan, N. Hirao and Y. Ohishi, Nature Phys. 12, 835 (2016).
[8] H. Nakao M. Einaga, M. Sakata, M. Kitagaki, K. Shimizu, S. Kawaguchi, N. Hirao and Y.
Ohishi: J. Phys. Soc. Jpn. 88, 123701 (2019).
[9] M. Sakata, M. Einaga, M. Dezhong, T. Sato, S. Orimo and K. Shimizu, Supercond. Sci.
Technol. 33 114004, (2020).

43

Session 4-C

Collaboration among Computation, Experiments and Mathematics
toward Next Generation Battery
Kazuto Akagi*
WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University
Exploration and design of new materials for energy devices is one of the important issuesof modern materials science. The data driven approach known as "Materials Informatics" hasbrought us drastic change in various ways, but it is not a magic. We may find better materials
by interpolation of a dataset based on machine learning techniques. But if we want to findnovel materials by extrapolation, appropriate modeling based on scientific understandings oftarget systems is indispensable.
In this talk, we will focus on some recent activities in the field of development ofhigh-performance next generation batteries, which is strongly expected from the viewpoint ofenvironmental problem. First, we will briefly introduce "Advanced Target Project" in AIMR
and "Fugaku Battery & Fuel Cell Project [1]" using the supercomputer Fugaku to see what are
the latest interests and challenges there.
Next, two key components in my own approach to achieve reliable classical molecular
dynamics simulations and enable quantitative characterization of large complex structural
data will be shown (Fig.1). The former one is a framework optimizing force field parameters
based on multi-objective genetic algorithm, and the latter one is topological data analysis
based on persistent homology [2], respectively. We will see how these methods are applied toobtain the scientific understandings of thermodynamic behavior of solid electrolyte systems
with hydride materials and polymer electrolyte systems for proton transport. Not only the
on-going collaborations but possible collaborations necessary to solve the problems will also
be mentioned.
[1] https://www.nims.go.jp/fugaku-denchi/en/index.html[2] Y. Hiraoka et al., PNAS 113, 7035-7040 (2016).

Fig. 1. Approach to battery materials by combination ofreliable large-scale MD simulation andtopological data analysis.

45

Student Session 2-A

XPS Analysis of Functional Oxides
Andreas Klein*
Technical University of Darmstadt, Department of Materials and Earth Sciences, Electronic
Structure of Materials Group, Otto-Berndt-Str. 3, 64287 Darmstadt, Germany
X-ray photoelectron spectroscopy (XPS) is widely used for the analysis of the chemicalcomposition and oxidation states of surfaces. Apart from chemical and composition analysis,
XPS can provide insights into the defect properties of the materials. This is provided by thepossibility to determine the Fermi energy and its variation with doping and preparation
conditions and its evolution during interface formation. Even highly insulating samples can beanalyzed either via measuring thin films on conducting substrates or by using thin conducting
top electrodes. As an example, Fig. 1 shows the Fermi energies of differently doped CeO2 thinfilms. These data can be directly compared with defect chemistry calculations. Large data sets
for a single material provide limits of the Fermi energy, which are directly related to thedominant compensation mechanism of doping.
Interface studies can reveal chemical interactions and help to understand the factors influencing Schottky barrier heights and heterojunction band alignment. By comparing with the Fermi
energy limits, a fundamental understanding of compensation mechanisms is possible (see Fig.
1). A description of XPS basics and its application to functional oxides can be found in [1-3].
[1] A. Klein, T. Mayer, A. Thissen, and W. Jaegermann, Photoelectron Spectroscopy inMaterials Science and Physical Chemistry: Analysis of Composition, Chemical Bonding
and Electronic Structure of Surfaces and Interfaces, Bunsenmagazin 10 (2008), 124.
[2] A. Klein, Energy band alignment at interfaces of semiconducting oxides: A review ofexperimental determination using photoelectron spectroscopy and comparison withtheoretical predictions by the electron affinity rule, charge neutrality levels, and thecommon anion rule, Thin Solid Films 520 (2012), 3721.
[3] A. Klein, Interface Properties of Dielectric Oxides, J. Am. Ceram. Soc. 99 (2016), 369.
[4] R. Schafranek, S. Li, F. Chen, W. Wu, and A. Klein, PbTiO3/SrTiO3 interface: Energy
band alignment and its relation to the limits of Fermi level variation, Phys. Rev. B 84
(2011), 045317.

Fig. 1: (left) Fermi energies of differently doped and treated CeO2 thin film samples deposited
onto Pt coated MgO(110) and c-cut sapphire substrates; (right) Variation of the Fermi energy
in BST and PZT films with aligned energy bands [4].

47Student Session 2-B

High-Temperature Acoustic Loss in Piezoelectric CTGS crystals
High-Temperature Acoustic Loss in Piezoelectric CTGS crystals
Y. Suhak, M.
Schulz,H. Fritze
High-Temperature Acoustic
Loss
in Piezoelectric
CTGS crystals

Y. Suhak, M. Schulz, H. Fritze
Institute of Energy
Researchand PhysicalTechnologies,
Y. Suhak,
M. Schulz,
H. Fritze
Institute ofClausthal
Energy Research
andofPhysicalTechnologies,
University
Technology
Clausthal University of Technology
Institute of Energy Research and Physical Technologies,
Clausthal University of Technology
High-temperature stable piezoelectric crystals of the langasite family show a broad
High-temperature
crystalsof theshow a broad
application
potential stable
in a piezoelectricwide temperature
range.
Forlangasite
example,family
the developmentofapplication
potential
inawide
temperature
range.
For
example,thedevelopmentof
high-quality
crystals stablesupports
the development
frequency
filters family[1]. Further,mass
High-temperature
piezoelectric
crystalsof ofthe langasite
show thea broadhigh-quality
crystalsdevelopment
ofoffers
frequency
filtersin[1].
Further,technology
the mass
sensitivity
ofpotential
resonantsupports
sensorsatthe
hightemperatures
advantages
theapplication
in a wide
temperature
range.
For
example,the sensor
development ofsensitivityofresonant
sensors
at hightemperaturesoffers advantages
in the sensor
technology
of
gases
or
soot
particlesandthus
supports
thedevelopment
andtheincreaseinefficiency
andhigh-quality crystals supports the development of frequency filters [1]. Further, the mass
of
gases
or
soot
particlesandthus
supports
thedevelopment
andtheincreaseinefficiency
andenvironmental
compatibility
conversion processes[2,3]. in the sensor technology
sensitivityof resonant
sensorsofatenergy
high temperaturesoffers advantages
environmental compatibility of energy conversion processes [2,3].
of gases or soot particles and thus supports the development and the increase in efficiency andPiezoelectriccompatibility
Ca3TaGa3Siof2Oenergy
14 (CTGS) crystals combine properties required forenvironmental
conversion processes [2,3].
Piezoelectric Ca
combineproperties
for
3TaGa3Si2O
14 (CTGS)
high-temperaturetransducers
like
excellent crystals
thermal andchemicalstability,required
high phasehigh-temperaturetransducersand
likelowexcellent
thermal andchemicalstability, highphasetransformation
temperatureselectromechanicallosses.
The
fundamental
resonance
Piezoelectric Ca3TaGa3Si2O14 (CTGS) crystals combine properties required fortransformation
temperatures andlow electromechanicallosses.
The fundamentaltemperatureresonance
properties of high-temperaturesuchandas maximum
high-temperaturetransducers piezoelectriclike excellentcrystals
thermalchemical operation
stability, high phase
properties
high-temperature
piezoelectric crystals
such asoperation
temperatureandlossesofare
reviewed. Atomistic
propertiesof maximum
langasite-type
crystals
are thentransformation
temperaturesand lowtransport
electromechanicallosses.
The fundamental
resonanceandlossesandarecorrelated
reviewed.with
Atomistictransport propertiesof langasite-type
crystals
are thendiscussed
electromechanicallosses.
Here,
the
focus
is
put
on
dominating
properties of high-temperature piezoelectric crystals such as maximum operation temperature
discussedand correlatedwith electromechanicallosses.
Here, thefocus
is putrelaxations.
on dominating
chargecarriers,
conductivity
relatedlossesandanelastic
point
defectFor
and losses are reviewed. Atomistic transport properties of langasite-type crystals are thenchargecarriers,
conductivity
relatedlossesandanelastic
point
defectrelaxations.
For
example, oxygen
transport
is foundto play a minor
role.Here,The analysis
is isappliednominally
discussedand correlated
withelectromechanicallosses.
the focus
put ontodominating
example,oxygencrystals
transportfrom
is found to playa minor role.
The showanalysis
is applied
to nominallyidenticalcarriers,
CTGS
which
impuritylevels.
chargeconductivity several
related manufacturers
losses and anelastic
pointdifferent
defect relaxations.
For
identical
CTGS crystals losses
from several
manufacturers
which show
different
impuritylevels.
Theelectromechanicalare
analyzedasafunctionoftemperature
from
room
example, oxygen transport is found to play a minor role. The analysis is applied to nominally
The electromechanicalare analyzed
as a functionof temperaturefrom room
temperature
up tocrystals
900 °Closses
and comparedwith langasite.
The overallloss and its
contributions
identical
CTGS
from
several manufacturers
whichshow different
impuritylevels.
temperature
up
to
900
°C
and
comparedwithlangasite.
Theoverall
loss
and
its
contributions
in CTGS
crystals are shown
Fig.analyzed
1. Further,
properties
includingTheelectromechanicallossesinare
as fundamental
a function materialof temperature
from
room
in
CTGS conductivity
crystals are shownin Fig. 1.
Further, arefundamental
material
propertiesone
includingelectricalandandresonance
frequency
monitored
overlossa period
year attemperature
up to 900 °C
comparedwith langasite.
The overall
and itsofcontributions
electricalconductivity
and resonancefrequency
monitored
over a period of one year at
1000°C andfound areto decrease
by Fig.
only1.
0.1Further,% and are0.4%, respectively.
in
CTGS
crystals
shown infundamental
material properties including
1000
°C
and
found
to
decrease
by
only
0.1
%
and
0.4
%,
respectively.
Finally,conductivity
application relevant
information
aboutareuncertainty
in overfrequency
determinationelectricaland resonancefrequency
monitoreda periodof one yearandatFinally,
application
relevant For
information
about
uncertaintyconditions,in frequency
determination
mass
sensitivity
ispresented.
the
given
experimentalamass
resolutionandof1000 °C and found to decrease by only 0.1 % and 0.4 %, respectively.
mass
For theoperated
given experimental
conditions,of50
ng sensitivity
is foundforis apresented.
CTGS
resonator
in uncertainty
thickness-shear
mode aatmass
aboutresolution
5 MHz andand
Finally,
application
relevant
information about
in frequency
determination
50 ng°C.is found for a CTGS resonator operated in thickness-shear mode at about 5 MHz and700
mass sensitivity is presented. For the given experimental conditions, a mass resolution of
700 °C.
50 ng is found for a CTGS resonator operated in thickness-shear mode at about 5 MHz and[1] H.
700°C.Kawanaka, H. Takeda, K. Shimamura, T. Fukuda, J. Crystal Growth 183, 274 (1998).
[1]
Kawanaka,
H. Takeda,
K.J.Shimamura,
Fukuda,J. Crystal
183, 274 (1998).
[2] H.
X. Jiang,
K. Kim,S. Zhang,
Johnson, G.T.Salazar,
Sensors
14, Growth
144 (2014).
[2]
X.
Jiang,K.W.
Kim,
S.
Zhang, A.
J. Johnson,
G.H.
Salazar,Sensors
14, 144MRS(2014).
[3]
Y.
Suhak,
L.
Johnson,Sotnikov,
Schmidt,
H.
Fritze,Advances
4, 515[1] H. Kawanaka, H. Takeda, K. Shimamura, T. Fukuda, J. Crystal Growth 183,274 (1998).
[3] Y.
Suhak,W.
L.
Johnson,A.
Sotnikov,H.
Schmidt,
H.
Fritze,MRSAdvances
4, 515(2019).
[2] X.
Jiang, K. Kim, S. Zhang, J. Johnson, G. Salazar, Sensors 14, 144 (2014).
(2019).
[3] Y. Suhak, W. L. Johnson, A. Sotnikov, H. Schmidt, H. Fritze, MRS Advances 4, 515(2019).

Fig. 1. Overall loss in CTGS and different temperature
Fig. 1. Overall
losslossin CTGSand different temperaturedependent
contributions.
dependent loss contributions.
Fig. 1. Overall loss in CTGS and different temperaturedependent loss contributions.
48

Student Session 2-C

Impact of the Surface Space Charge Region on the Charge Transport inOxides for Energy Applications
Matthias T. Elm1*
1

Center for Materials research, Justus-Liebig University Giessen, Heinrich-Buff-Ring 16,35392 Giessen*Matthias.elm@phys.chemie.uni-giessen.deIon-conducting ceramic oxides are widely used for various applications in the field ofelectrochemical energy storage. While ceria and zirconia-based materials are used as electrolyte
or electrode material for oxygen storage devices or solid oxide fuel cells, LiCoO2-based
ceramics are still the state-of-the art electrode material for lithium-ion batteries. In both cases,
the electrode material exhibits a complex, porous architecture with a high surface area to ensure
on the one hand the transport of the electronic and ionic charge carriers within the porous
framework and on the other hand the exchange of oxygen with the surrounding atmosphere or
the exchange of lithium ions with the electrolyte, respectively. However, due to the high grainboundary density and surface area, the material may exhibit different electronic an ionictransport properties compared to the bulk. The reason is that at interfaces the local symmetry is
broken, resulting in the formation of a space charge region with different defect-chemical
properties compared to the bulk. Especially in nanostructured materials, where interface effects
can dominate the overall behavior, the space charge region may significantly alter the electricalproperties. As the working principle of all electrochemical devices is based on the transport ofcharged carriers, a fundamental understanding of the defect-chemistry at the interfaces isneeded to further optimize the device performance for applications.
The talk will give an overview on recent results on the electrochemical investigation of thetransport properties of (meso)porous oxide thin films. Due to their high surface-to-volume ratio,these films present an ideal model system to study the influence of the surface properties on theelectronic and ionic transport processes. The results reveal an increased electronic conductivity
in porous oxygen-ion conductors due to the formation of a space charge region, not only in thecase of mixed-conducting ceria but also for YSZ, whose bulk pendant is a purely ionic
conductor. Furthermore, in these oxides protonic surface conductivity arises, which can bealtered by modifications of the surface [1]. Finally, the talk will discuss the influence of thespace charge region on the lithium storage capacity in mesoporous Nb-doped TiO2 [2], which
represents a promising anode material for lithium ion batteries.
[1] E. Celik, R.S. Negi, M. Bastianello, A. Maziklin, T. Brezesinski, M.T. Elm, Phys. Chem.
Chem. Phys. 22, 11519 (2020).
[2] J. Yue, C. Suchomski, P. Voepel, R. Ellinghaus, M. Rohnke, T. Leichtweiss, M.T. Elm,
B.M. Smarsly, J. Mater. Chem. A 5, 1978 (2017).

51

Student Session 2-D

Catalytic Activity of Cobalt-Based Oxides for the Cathodic Reaction of ITSOFC
Yuto Tomura, Toma Tazawa, Itaru Oikawa and Hitoshi Takamura
Department of Materials Science, Graduate School of Engineering, Tohoku University,
Sendai 980-8579, Japan
Cobalt-containing oxides such as LSC and BSCF are well-known to exhibit a superior oxygen
reduction reaction (ORR) activity at intermediate temperatures for IT-SOFC. Even though theirperovskite-type structure having a large amount of highly mobile oxygen vacancies is definitely
responsible for their cathode performance, the catalytic activity of cobalt element itself is notwell understood. The focus of this study is then to clarify its catalytic activity at intermediate
temperatures apart from the perovskite-type structure. In this investigation, a modified pulse
isotopic exchange technique was used to quantitatively evaluate the dissociative adsorption rateof Co–Fe-based spinel-type and Co–Mg-based rock salt-type oxides. The catalytic activity
increased with increasing concentrations of the Co ion regardless of crystal structure. The nonlinear relationship between the catalytic activity and the Co concentration indicated that the
improvement in the catalytic activity of the Co-rich samples by the formation of Co clusters isgreater than that resulting from a simple increase in the number of Co ions (Fig. 1). That effectwas likely more remarkable in the Co-rich system because of the outstanding catalytic activityof Co3O4, which is comparable to the overall surface exchange rate of MIECs, and its relatively
low activation energy compared to Fe-containing spinel-type oxides. The importance of the Co
element in catalytic activity at high temperatures was confirmed [1].

Fig. 1: Dissociative oxygen adsorption rate (Ra) as a function of Co area fraction for Co-Mg
and Co-Fe-based oxides.
[1] Y. Tomura, T. Tazawa, I. Oikawa and H. Takamura, J. Mater. Chem. A, in press.

53

Student Session 2-E

Flat Visible-Light Absorption Properties of Inorganic Thin Films Preparedby Pulsed Laser Deposition
Mina Yamaguchi1, Akihiro Ishii1, Itaru Oikawa1, Yusuke Yamazaki2, Masaaki Imura2,
Toshimasa Kanai2 and Hitoshi Takamura1
1

Department of Materials Science, Graduate School of Engineering, Tohoku University,
Sendai, Japan
2
Nippon Electric Glass Co., Ltd.

Preference for a classy black turn-off appearance and for distinct dark colors on flat-panel
displays has led to a high demand for optically black materials. For use in flat-panel displays,
the black materials must have three non-negotiable properties. They are required to have a large
optical density (i.e. high magnitude of absorbance), have absorption which is less wavelengthdependent in the visible range (λ=400–700 nm), and also be homogeneous at the micro scale to
avoid light scattering. It is difficult to satisfy these three requirements simultaneously. Ourgroups developed a newly concept that is coexistence of semiconducting absorption andmetallic absorption mechanisms and controlling the composition.
NbxTi1−xO2, a solid solution combining the reduced titanium and niobium oxide phases wereprepared by pulsed laser deposition (PLD), and their optical absorption properties were shown
to be large in magnitude at an almost constant value of ≈17 µm−1. Localized Nb-Nb dimers in
the metallic NbxTi1−xO2 phase open an optical band gap which gives rise to semiconducting
behavior [1]. Ti-O-N and tungsten-doped Ti-O-N prepared using nitrogen plasma assisted PLD
also show the large and flat absorption coefficient of approximately 40 μm−1 in the visible range.
The 4.1 mol%W-doped Ti(O,N)x, which had a rock-salt-type structure, was optically jet-black.
The origin of the flat wavelength dispersion in the W-doped Ti(O,N)x was attributed to thecoexistence of semiconducting absorption and metallic absorption mechanisms. DFT
calculations suggest that the 5d states achieved when using doped tungsten provide highabsorption in the mid-wavelength range, whereas undoped-Ti(O,N)x was characterized by weakabsorption [2].
In addition to a flat and large absorption coefficient in the visible range, an electricallyinsulative property is required for the application of the touch-panel displays; however, it isdifficult to achieve these properties simultaneously in single phase because they are basicallytrade-off relation. Nano-sized metal particles dispersed into an insulator matrix are focused onin this study, in which the coexistence of free-carrier absorption of metal and inter-band
absorption of insulator is expected. Cu-Bi2O3 and Ag-Fe2O3 thin films were prepared by PLD.
The 30mol%Cu-Bi-O films and the 45mol%Ag-Fe-O thin films showed the large and the flat
absorption in visible range. These sample have large sheet resistance (Rsheet>108 ohm/sq.) eventhough the Cu and Ag peaks were observed in the XRD patterns, respectively. The ADF-STEM
image of the Ag-Fe-O thin film shows three phases mixed in nanometer scale. These phases
were identified as metallic Ag, spinel iron oxide and amorphous Ag-Fe-O phase from theelement mapping and the electron diffraction pattern. In this thin film, Ag was separated
partially by the insulator matrix, which have Ag and large resistance. This microstructure seems
to be responsible for the electrically insulative property even for high Ag content.
[1] A. Shimabukuro, A. Ishii, I. Oikawa, Y. Yamazaki, M. Imura, T. Kanai and H. Takamura,Appl. Surf. Sci. 464, 61 (2019).
[2] M. Yamaguchi, A. Ishii, I. Oikawa and H. Takamura, Appl. Surf. Sci. 534 147616 (2020).
[3] A. Ishii, M. Yamaguchi, I. Oikawa, Y. Yamazaki, M. Imura, T. Kanai and H. Takamura,phys, status solidi RRL, 14, 2000160 (2020)54

Student Session 3-A

Basic Properties of Vesicles as Biomaterials
Peter Walde
Laboratory for Multifunctional Materials, Department of Materials, ETH Zürich,
Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland
Amphiphilic molecules − with their hydrophilic and hydrophobic parts − are fascinating
molecules since they assemble in aqueous solution into various types of polymolecularaggregates. SDS (sodium dodecylsulfate), for example, is a simple micelle-forming surfactant.
Highly dynamic, thermodynamically stable, spherical SDS micelles form in water above thecritical micellization concentration (CMC) and above the critical micellization temperature(CMT). Other types of aggregates may also form from amphiphiles in aqueous solution. It
depends on (i) the chemical structure of the amphiphile, (ii) the concentration, (iii) thetemperature, (iv) the composition of the aqueous solution, and - in many case - (v) the way theamphiphiles are brought in contact with the aqueous solution. In the latter case, the aggregatesobtained are only kinetically stable and not thermodynamically). The phospholipid POPC
(1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) belongs to this category. It is a typicalbilayer-forming amphiphile, and is present in the lipid matrix of eukarytic membranes. POPC
does not form micelles since the hydrophobic part is too large. Instead, POPC assembles intobilayers which self-close into vesicles in dilute aqueous solution, usually micrometer-sized
multilamellar vesicles (MLVs), whereby several self-closed bilayers are arranged
concentrically. Upon storage, MLVs sediment and form a separate phase, in equilibrium withthe aqueous solution. For obtaining submicrometer-sized dispersed unilamellar POPC lipid
vesicles (also called liposomes), the POPC molecules have to be "guided" during theassembly process or the MLVs obtained have to be sized-down mechanically. Unilamellar
vesicles of a certain size and lamellarity are obtained by "guided assembly" and not by true
self-assembly. Such vesicles can be stable for days or months if the energy barrier for vesicle
fusion to MLVs is high. Similarly to lipid vesicles, vesicles can also be obtained fromsynthetic bilayer-forming amphiphilic block copolymers. They are called polymer vesicles orpolymersomes.
Liposomes and polymersomes with their trapped aqueous volume and soft membrane areversatile compartment systems. They are investigated or already commercially applied as
biomaterials in the field of drug delivery, even with considerations for possible futureapplications as artificial organelles.

57

Student Session 3-B

Bottom up approaches to synthetic cellularity

T-Y Dora Tang
Max Planck Institute for Cellular Molecular Biology and Genetics
Pfotenhauer Strasse 108, 01307 Dresden, Deutschland
Biology is well equipped in exploiting a large number of out of equilibrium processes
to support life. A complete understanding of these mechanisms is still in its infancy due to thecomplexity and number of the individual components involved in the reactions. However, abottom up approach allows us to replicate key biological processes using a small number ofbasic building blocks. Moreover, this methodology has the added advantage that properties
and characteristics of the artificial cell can be readily tuned and adapted.
Here, I will present strategies for the design and synthesis of artificial cells based onhydrophobic effects such as lipid vesicles and proteinosomes and liquid-liquid phaseseparation of oppositely charged components (coacervates) and describe how thesecompartments may be used as platforms for implementing dynamic biological behaviours
including: intercellular communication or autocatalysis.

59

Student Session 3-D

Sustainable Reproduction of Vesicles
coupled with Surface Confined Template Polymerization
Minoru Kurisu1*, Peter Walde2 and Masayuki Imai1
1

Laboratory for Soft Matter and Biophysics, Department of Physics, Tohoku University
2
Laboratory for Multifunctional Materials, Department of Materials, ETH Zürich

Construction of autonomously reproducing molecular assembly system from simple soft
matter is one of the key approaches to understand what bridges non-living and living forms ofmatter. Here we show a sustainable growth and division (i.e. reproduction) of cell-size
vesicles coupled with mutual catalytic relationship between vesicle membrane and membranesurface-confined polymerization [1]. Mutual catalytic relationship has been considered as animportant clue to construct self-reproducing molecular system [2]. Concerning to the mutual
catalysis, template polymerization reaction is a promising system in which monomers arearranged by a preformed macromolecule (template), and then they are polymerized interactingwith the template. In order to construct reproduction system with vesicle and polymer, we
focused on template polymerization of aniline on the surface of vesicle composed of AOT(i.e. sodium bis-(2-ethylhexyl) sulfosuccinate) [3]. In this system, polymerization reaction is
localized on the vesicle surface, and specific form of polyaniline (polyaniline emeraldine saltform) is obtained due to interactions between AOT and polyaniline. In addition, polyaniline
synthesized on the AOT vesicle surface promote selective incorporation of membrane
molecules from bulk solution. As a result, synthesis of specific form of polyaniline andgrowth of membrane that works as template for the polyaniline is coupled: mutual catalytic
relationship between polymer and membrane. To the vesicle growth system, we thenintroduced spontaneous vesicle division mechanism. Coupling between geometry ofmembrane molecules and local membrane curvature is known to be an important molecularmechanism which enables spontaneous vesicle division without the help of sophisticatedbiological mechanism such as using cytoskeleton protein [4, 5]. In our case, we introducedcholesterol as the second membrane molecules to the vesicle growth system composed of
AOT and polyaniline, and we succeeded in realizing sustainable growth and division cycles ofvesicle. This vesicle reproduction system is constructed not from complicated biologicalmolecular system such as using nucleic acid and protein, but from simpler chemical reactions
and components. We expect that the development of this work will give a contribution for
discussing what is the minimal form of life, how it can emerge from non-living system andhow it is stabilized.
[1]Kurisu, M. et al., Communications Chemistry, 2:117(2019)[2]Eigen, M. and Schuster, P. “The Hypercycle”, Springer, Germany (1979)[3]Junker, K. et al., RSC Advances, 2, 6478–6495 (2012)[4]Sakuma, Y. et al., Physical Review Letters, 107, 198101 (2011)[5]Jimbo, T. et al., Biophysical Journal, 110, 1551-1562 (2016)60

Session 5-A

Theoretical approaches to topological materials
Shuichi Murakami1,2*
1

Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku,
Tokyo 152-8551, Japan.
2
Materials Research Center for Element Strategy,
Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
Topological materials have been attracting much interest in condensed matter physics. To
date, thousands of materials have been identified to be topological by combining theories on
topological materials with materials databases in an automatic way. Meanwhile, apart fromautomated searches, we need deeper understanding on topological nature of topologicalmaterials, from the materials science perspective. In my presentation, we explain a series of
our works to understand their origins from various theoretical viewpoints. For example,
studies on topological-nontopological phase transitions have shown us a new class of
topological materials called topological semimetals, which have been established among thefamily of topological materials [1,2]. Remarkably, the notion of topological materials also
brings about renewed interest on the known materials, such as bismuth bilayer film as a
two-dimensional topological insulator [3], and alkaline earth metal calcium at high pressure asa topological nodal line semimetal [4]. Furthermore, we propose that electrides, in whichelectrons serve as anions in ionic crystals, are good candidates for topological materials[5,6,7]. Recently we also study higher-order topological insulators, in which boundary gaplessstates appear at corners and hinges of the crystals [7]. We show that in higher-order
topological insulators, the dependence of the hinge states/corner states on crystal shapes show
new features unique to higher-order topological insulators.
[1] S. Murakami, New J. Phys. 9, 356 (2007).
[2] S. Murakami, M. Hirayama, R. Okugawa, and T. Miyake, Sci. Adv. 3, e1602680 (2017).
[3] S. Murakami, Phys. Rev. Lett. 97, 236805 (2006).
[4] M. Hirayama, R. Okugawa, T. Miyake, and S. Murakami, Topological Dirac Nodal Linesand Surface Charges in fcc Alkaline Earth Metals, Nat. Commun. 8, 14022 (2017).
[5] M. Hirayama, S. Matsuishi, H. Hosono, and S. Murakami, Phys. Rev. X 8, 031067 (2018).
[6] M. Hirayama, R. Okugawa, and S. Murakami, J. Phys. Soc. Jpn. 87, 041002 (2018).
[7] M. Hirayama, R. Takahashi, S. Matsuishi, H. Hosono, S. Murakami, arXiv:2004.03785 (toappear in Phys. Rev. Research).

63

Session 5-B

Morphology of Crystals in Melt Growth Processes
Kozo Fujiwara1*
1Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai,
980-9577 Japan

A lot of crystalline materials are produced by solidification/crystal growth from melts. The
morphologies of crystal and crystal-melt interface during crystallization processes affectmicrostructure of crystalline materials. Therefore, it is important to understand how themorphologies of crystal and crystal-melt interface are formed during crystallization processes.
Usually, it is difficult to observe the crystal-melt interface directly in the melt growth
processes since the melting point of inorganic materials is high. Therefore, we have developed
an in-situ observation system which consists of a crystal growth furnace and a digital
microscope [1]. That system enables us to observe crystal growth processes at an elevatetemperature more than 1000℃. In this presentation, we will show the crystal growth shapes
upon a normal growth and a dendritic growth from Si melt. The morphological transformationof crystal-melt interfaces of some crystalline materials will also be shown.
Figs. 1 (a) and (b) show Si crystals growing upon a normal growth mode and a dendritic
growth mode from Si melts. It is found that the shape of Si dendrite is different from that ofwell known dendrites of metallic alloys. We will show that when a crystal contains twoparallel twin boundaries, the growth kinetics at the crystal/melt interface changes and the
crystal initiates dendritic growth [2]. The growth mechanism of this dendrite is different fromthe dendrites of metallic materials. We could observe such the dendrite growth caused by twinboundaries also in GaSb compound semiconductor [3].
Fig. 2 shows a morphological transformation of planar crystal-melt interface tozigzag-faceted interface during unidirectional solidification of Si [4]. This phenomenon is
known as the interface instability. We will show that the interface instability is promoted
when a growing crystal contains grain boundaries [5].
[1] K. Fujiwara, Y. Obinata, T. Ujihara, N. Usami, G. Sazaki, K. Nakajima, J. Crystal Growth 262,
124-129 (2004).
[2] K. Fujiwara, K. Maeda, N. Usami, K. Nakajima, Phys. Rev. Lett. 101, 055503 (2008).
[3] K. Shiga, M. Kawano, K. Maeda, H. Morito, K. Fujiwara, Scr. Mater. 168, 56-60 (2019).
[4] M. Tokairin, K. Fujiwara, K. Kutsukake, N. Usami, K. Nakajima, Phys. Rev. B 80, 174108 (2009).
[5] K. K. Hu, K. Maeda, K. Shiga, H. Morito, and K. Fujiwara, Materialia 7, 100386 (2019).
(b)(a)
Si melt

melt

Si crystal

melt

<112>

<110>
1 mm

500μm

crystal<110>

crystal

100 μmFig. 1 Si crystals growing in the (a) normal growth and(b) dendritic growth mode.

65

Fig. 2 Instability of crystal-melt interface of Si.

Session 5-C

Nanometer-scale local crystal structure analysis
using convergent-beam electron diffraction
Kenji Tsuda*
Frontier Research Institute for Interdisciplinary Sciences (FRIS),
Tohoku University, Sendai 980-8578, Japan*email: k_tsuda@tohoku.ac.jp
Novel physical properties caused by local crystal structures such as relaxors have beenreported increasingly. Convergent-beam electron diffraction (CBED) is an analysis method
suitable for examining such nano-scale local crystal structures with the use of ananometer-sized electron probe. It was established as the most powerful technique todetermine crystal point- and space-groups [1]. We have been developing a quantitative
analysis method to determine structural parameters based on fitting between experimental
CBED intensities and dynamical diffraction (multiple scattering) simulations [2-4].
Electrostatic potential and electron density distributions of a local specimen area can bereconstructed from the determined structural parameters.
An important issue of the CBED is to develop a method for examining specimens withlocal structural variations. For this purpose, combined use of scanning the transmission
electron microscopy (STEM) and the CBED was proposed (STEM-CBED) [5], where CBED
patterns are acquired pixel-by-pixel by scanning the electron probe with a sub-nanometer scanstep. Using the STEM-CBED method, we investigated local structures of perovskite-type
ferroelectric oxides. Nano-scale spatial fluctuations of the rhombohedral polarization clusters
were successfully visualized in both of the ferroelectric and paraelectric phases of BaTiO3 andKNbO3 [5-8]. These results provide crucial information on the mechanism of the structuralphase transformations of these ferroelectrics. The STEM-CBED was recently applied forvisualizing ferroaxial domains in NiTiO3 [9], where rotational structural distortions offerroaxial domains were observed with the aid of higher-order Laue zone reflection disks.
Another important issue of the CBED is to improve the sensitivity and accuracy of thequantitative structure analysis using CBED patterns. A promising way for this is the use of thelarge-angle CBED (LACBED) method [1], which is a technique to obtain intensity
distributions of CBED reflection disks in a larger angular range beyond the Bragg angle. In
a Fe 3d orbital-ordered phase of FeCr2O4, it was demonstrated that electron density
distributions of the Fe 3d orbitals can be successfully reconstructed using LACBED data
through excitation of characteristic Bloch waves [10]. Application of machine learning will be
discussed for reducing computing time needed for LACBED simulations.
References:[1] e.g. Tanaka and Tsuda, J. Electron Microsc., 60, S245 (2011).
[2] Tsuda and M. Tanaka, Acta Cryst., A55, 939 (1999).
[3] Ogata, Tsuda and Tanaka, Acta. Cryst., A64, 587 (2008).
[4] Tsuda et al., Phys. Rev. B, 81, 180102 (2010).
[5] Tsuda, Yasuhara and Tanaka, Appl. Phys. Lett., 102, 051913 (2013).
[6] Tsuda and Tanaka, Appl. Phys. Express, 8, 081501 (2015).
[7] Tsuda and Tanaka, Appl. Phys. Express, 9, 071501 (2016).
[8] Tsuda and Tanaka, Jpn. J. Appl. Phys., 56, 10PB09 (2017).
[9] Hayashida et al., Nat. Commun., 11, doi:10.1038/s41467-020-18408-6 (2020).
[10] Morikawa and Tsuda, Microsc., doi:10.1093/jmicro/dfaa041 (2020).

67

GP-MS Session A

Abnormal Raman Modes in Janus Monolayers and Weyl Semimetals
Shengxi Huang1
1

Department of Electrical Engineering, The Pennsylvania State University, University Park,
Pennsylvania 16802 United States

In this talk, I will discuss the abnormal Raman modes that we have discovered recently for
two material systems: Janus monolayer and Weyl semimetal. Janus transition metal
dicalcogenide (TMD) is a newborn of the two-dimensional (2D) materials family [1]. Its
structure is similar to TMDs such as MoS2, but one layer of chalcogen is different from theother layer, one example being MoSSe. Due to the unique crystal structure of Janus TMD and
the induced out-of-plane dipole moment, we found that Janus monolayer enhances theinterlayer coupling when forming van der Waals heterostructures, observed in the
low-frequency Raman spectroscopy [2]. On the other hand, Weyl semimetals are a
recently-discovered class of topological materials with numerous peculiar properties including
chiral anomaly, surface Fermi arc, giant optical nonlinearity, etc. [3] We have observed thebroken Raman symmetry and the polarization dependent Fano line shape [4]. The
unconventional phenomena can be attributed to the unique electronic band structures andphonon dispersions. Both works demonstrated that Raman spectroscopy is an effective tool toprobe the material structure and interface coupling, and can be correlated with electronic
properties.
[1] Lu, A.Y., Zhu, H., Xiao, J., Chuu, C.P., Han, Y., Chiu, M.H., Cheng, C.C., Yang, C.W.,
Wei, K.H., Yang, Y. and Wang, Y., 2017. Janus monolayers of transition metal
dichalcogenides. Nature Nanotechnology, 12(8), pp.744-749.
[2] Zhang, K., Guo, Y., Ji, Q., Lu, A.Y., Su, C., Wang, H., Puretzky, A.A., Geohegan, D.B.,
Qian, X., Fang, S. and Kaxiras, E., 2020. Enhancement of van der Waals interlayer
coupling through polar Janus MoSSe. Journal of the American Chemical Society. In
press.
[3] Xu, S.Y., Belopolski, I., Alidoust, N., Neupane, M., Bian, G., Zhang, C., Sankar, R.,
Chang, G., Yuan, Z., Lee, C.C. and Huang, S.M., 2015. Discovery of a Weyl fermion
semimetal and topological Fermi arcs. Science, 349(6248), pp.613-617.
[4] Zhang, K., Pang, X., Wang, T., Han, F., Shang, S.L., Hung, N.T., Nugraha, A.R., Liu,
Z.K., Li, M., Saito, R. and Huang, S., 2020. Anomalous phonon-mode dependence inpolarized Raman spectroscopy of the topological Weyl semimetal TaP. Physical Review
B, 101(1), p.014308.

71

GP-MS Session B

Circularly Polarized Raman Scattering of Two-Dimensional Materials
Lianming Tong*
Center for Nanochemistry, College of Chemistry and Molecular Engineering, Peking
University, Beijing 100871, P.R. China*Email: tonglm@pku.edu.cn
Raman spectroscopy is a powerful tool for the characterization of materials. The peak
positions correspond to the energies of specific phonons, which give information on thecomposition and the lattice structures of materials. The intensity is determined by the opticaltransitions and the coupling between electrons and phonons. Generally, a linearly polarizedlaser is used for excitation. However, circularly polarized Raman scattering can provide more
information that is not accessible by linear polarization.
In this talk, I will introduce our recent work on circularly polarized Raman scattering of
two-dimensional (2D) materials. 2D materials are layered crystals of atomic thickness withintralayer chemical bonding but interlayer van der Waals interaction, which possess superior
optical, electrical, mechanical and thermal properties. Raman scattering has been widely used
to characterize the fine structures of 2D materials, such as layer number, defects and type ofedges. In our work, we use circularly polarized laser for the excitation of Raman scattering inlayered MoS2 and ReS2. MoS2 belongs to a hexagonal crystal family, and the point group of
the unit cell for bulk MoS2 is D6h. ReS2 is anisotropic and belongs to triclinic crystal family.
The schematic of helicity-resolved Raman scattering and the corresponding Raman spectraof MoS2 are shown in Figure 1. By helicity-resolved, the helicity of Raman scattered light isalso resolved and compared to that of the incident light.[1] Using this technique, wecharacterized the excitonic nature and evaluated the relative contribution of the two kinds ofelectron/exciton−phonon interactions, that is, deformation potential (DP) or the Fröhlichinteraction (FI).[2-3] On the other hand, for ReS2, we observed distinct difference in Raman
spectra excited by left- and right-handed circularly polarizations (LCP and RCP) even without
the selection of helicity. This phenomenon is attributed to the different phase factors ofelectron-photon matrix elements excited by LCP and RCP. The difference is then amplified
by the electron-phonon coupling.[4][1] Y. Tatsumi, T. Kaneko, and R. Saito, Phys. Rev. B 97, 195444(2018).
[2] Y. Zhao, S. Zhang, Y. Shi, Y. Zhang, R. Saito, J. Zhang, and L. Tong, ACS Nano 14,
10527 (2020).
[3] Y. Zhao, S. Han, J. Zhang, and L. Tong, J. Raman Spectrosc. 2020, DOI:
10.1002/jrs.5996.
[4] S. Zhang, J. Huang, Y. Yu, S. Wang, T. Yang,* Z. Zhang, J. Zhang, and L. Tong*, inprepration.

Fig. 1. Schematic of helicity-resolved Raman scatteringand corresponding Raman spectra of MoS2.

73

GP-MS Session C

Double Resonant Raman Scattering in TMDCS
Teng Yang1*, Jianqi Huang1*, Huaihong Guo2 and Riichiro Saito3
1

Shenyang National Laboratory for Materials Science, IMR, CAS, Shenyang, China
2
College of Sciences, Liaoning Shihua University, Fushun, China
3
Department of Physics, Tohoku University, Sendai, Japan

Raman spectra of TMDCs have been reported for several decades. The first-order Ramanprocess in TMDCs has been widely investigated and is now well understood. However, thestudy of second-order Raman spectra has not yet given consistent assignments for different
TMDCs. We study the second-order Raman process of monolayer TMDCs, by combining ab
initio density functional perturbation calculations with experimental Raman spectroscopy andelectron-phonon Wannier (EPW) method [1-4]. The calculated electronic band structure andthe density of states show that the resonance Raman process occurs at the M point in the
Brillouin zone (Figure 1), where a strong optical absorption occurs due to a logarithmic Van
Hove singularity of the electronic density of states. The double resonance Raman process withintervalley electron-phonon coupling connects two of the three inequivalent M points in the
Brillouin zone, giving rise to second-order Raman peaks due to the M-point phonons. The
calculated vibrational frequencies and laser-energy dependent Raman spectra of thesecond-order Raman spectra agree with the observed laser-energy-dependent Raman shifts inexperiment. We also predicted the polarization dependence of the double resonant Raman
modes.
[1] H. Guo, T. Yang, M. Yamamoto, L. Zhou, et al., Phys. Rev. B 91, 205415 (2015).
[2] Hsiang-Lin Liu, Huaihong Guo, et al., Phys. Chem. Chem. Phys. 17 (22), 14561 (2015).
[3] R. Saito, A. R. Nugraha, E. H. Hasdeo, S. Siregar, Huaihong Guo, Teng Yang, Physica
Status Solidi B 252 (11), 2363–2374 (2015).
[4] Hsiang-Lin Liu, Teng Yang, Yuki Tatsumi, Ye Zhang, Baojuan Dong, Huaihong Guo, etal., Scientific Reports 8, 11398 (2018).

Figure 1. (left) Raman intensity of one mode in the Brillouin zone at a certain laser energy.
(right) The schematics of the double resonance process (electron-photon and electron-phonon
processes).

*This document should consist of one page in A4 size.

75

POSTER ABSTRACTS:
Materials ScienceP-1

Innovative Strategies for High-Performance Cross-linked Polymer
Electrolytes for Rechargeable Lithium Ion Batteries
Manjit Singh Grewal1, Kazuaki Kisu1, Shin-ichiro Orimo1,2, Hiroshi Yabu1
1

WPI-Advanced Institute of Materials Research (WPI-AIMR), Tohoku University, 2-1-1,
Katahira, Aoba-Ku, Sendai 980-8577, Miyagi Japan,
2
Institute of Materials Research (IMR), Tohoku University, 2-1-1, Katahira, Aoba-Ku, Sendai
980-8577, Miyagi Japan)
1
TEL/FAX: ＋81-22-217-6341/6342, E-mail: grewal.manjit.singh.d3@tohoku.ac.jp,
hiroshi.yabu.d5@tohoku.ac.jp
Present work aims for an attempt to simultaneously improve the functions and properties inan electrolyte based on cross-linked network polymer comprising solvate ionic liquids that
represent an emergent class of innovative polymer electrolytes. Such electrolytes arepromising as they possess not only sufficient mechanical properties to separate the electrodes,
but also provide as high ionic conductivity as possible, as high a transference number of theactive cation as possible, and form a good, electrochemically stable interface with both of theelectrode materials (1-3).
This presentation will highlight work on a series of free-standing cross linked network
polymer electrolytes prepared from poly(ethylene glycol) diacrylate (PEGDA) prepolymer
host in low molar ratios plasticized by different concentrations of solvate ionic liquids(equimolar tetraglyme and bis(trifluoromethane) sulfonamide lithium (LiTFSI) salt) via
solvent-free photo-induced cross-linking. In this manner of concurrent exploitation ofphoto-induced cross-linking and in situ functionalization procedures, kinetically driven
inhibition of the PEG-chains crystallization is readily achievable at ambient conditions,leading to polymer electrolytes that possess high mechanical stiffness as well as liquid-likeion motions. The as-prepared polymer networks exhibited excellent comprehensive
performance in terms of high ionic conductivity (1.0 × 10-4 S cm-1 at 45 °C), a wide
electrochemical window (4.5 V), high lithium ion transference number (0.45), good uniform
lithium stripping and plating profiles under long hours of cell operation.
We envisage that the proposed approach for innovative soft polymer electrolytes would
lead to a rational designing to address the existing challenges of lithium ion polymer batteries.
References:
1. M. S. Grewal, K. Kisu, S. Orimo, H. Yabu, Chem. Lett., 2020, 49 |doi:10.1246/cl.2005722020.
2. L. Porcarelli et al., Sci. Rep. 6, 2016, 19892.
3. M. S. Grewal, M. Tanaka, H. Kawakami, Electrochim. Acta, 15, 2019, 307, 148.

78

P-2

Unveiling the lithium-oxygen electrochemistry by in situ liquid celltransmission electron microscopy
Jiuhui Han1,2, Chen Hou1, Chuchu Yang1, and Mingwei Chen1,3
1
2

WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University
Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University
3
Department of Materials Science and Engineering, Johns Hopkins University

In situ transmission electron microscopy (TEM) is emerging as a powerful tool for studying
micro- and nanoscale dynamic phenomena in real-time and real-space. In particular, therecently developed liquid-cell TEM has opened up new opportunities to investigate chemicaland electrochemical reactions in liquid media. Here we present the utilization of in situ
liquid-cell TEM for investigating the fundamental electrochemistry of non-aqueous
lithium-oxygen (Li-O2) battery, the emerging energy storage system that can theoreticallydeliver ten times more energy than today’s lithium-ion batteries. By directly visualizing the
dynamic processes of the Li-O2 reactions during synchronized electrochemical measurements,
in situ TEM has identified where/when/how the discharge products accumulate and evolve, as
well as their correspondence to the electrochemical responses with spatially and time-resolved
capabilities. These studies provide important insight into the fundamental mechanisms, suchas the reaction pathways and kinetics, of Li-O2 batteries and the working principles of solidand liquid catalysts.
[1] C. Hou†, J. H. Han†, P. Liu, G. Huang, and M. W. Chen, Nano Lett. 20, 2183-2190 (2020).
[2] C. Hou, J. H. Han, P. Liu, C. C. Yang, G. Huang, T. Fujita, A. Hirata, and M. W. Chen,
Nano Energy 47, 427-433 (2018).
[3] C. C. Yang†, J. H. Han†, P. Liu†, C. Hou, G. Huang, T. Fujita, A. Hirata, and M. W. Chen.
Adv.Mater. 29, 1702752 (2017).
[4] J. H. Han, K. Watanabe, and M. W. Chen, Operando observations of Li-O2 reaction
dynamics, in Analysis and Evaluation Technology of Lithium-Ion Batteries, Technical
Information Association Inc., pp. 453-464 (2019).

79

P-3

The Large Magnetoresistance in BaMn2Bi2 Antiferromagnet
and its Possible Origins
K.-K. HuynhA, T. OgasawaraB, S. Y. MatsushitaA, M. KimataC,
T. TaharaD, T. KidaD, M. HagiwaraD, K. TanigakiAA

WPI-AIMR, Tohoku University,
Dept.Phys, Grad. Sch. Science, Tohoku University,
C
Inst. Mat. Res. (IMR), Tohoku University,
D
Advanced High Magnetic Field Science, Grad. Sch. Science, Osaka University
B

BaMn2Pn2 compounds, in which Pn denotes a pnictogen element, areintriguing antiferromagnets with a (122) tetragonal layered structure
and a G-type antiferromagnetic ordering (AFM) of Mn2+ sublattice.
Whereas the crystal structure resembles that of the (122) iron pnictide
superconductors, the G-type AFM along the c-axis results in themagnetic point group 4’/m’mm’. This point group is odd under bothtime reversal (TR) and space inversion (SI) but even under the
combination symmetry PT = TR×SI. Theoretical studies of BaMn 2Pn2
predicted novel physical phenomena, such as a magnetic hexadecapole
order and a current induced nematicity, as the consequences of this Fig 1: BaMn2Pn2
symmetry [1]. On the other hand, the orbital degree of freedom of the half-filled 3d-shell of
the Mn2+ provides another interesting aspect and some studies suggested that these materials
show an orbital-selective magnetism being near to a Mott transition [2].
In its temperature-resistivity curve, a BaMn 2Pn2 exhibitsa metal-to-insulators transition from a bad metallic
behavior to an insulating-like as the temperature
decreases. In our previous study, we reported a verylarge positive magnetoconductivity (MC) appearing in
the insulating regime of all BaMn2Pn2 compounds [3].
As shown in Fig. 2, the MC appears large only undermagnetic fields perpendicular to the Neel vector and its
magnitude is sufficient to re-introduce the metallic statein the case of BaMn2Bi2. The origin of the MC and how
it connects to the AFM as well as to the hexadecapole
order have remained unclear. In this report, we approach
this question by studying the insulating regime underzero magnetic fields of BaMn2Bi2. Our study suggeststhat the insulating behavior of BaMn2Bi2 does not Fig 2: Large MC in BaMn2Bi2
originate from a band gap but rather from a localizationof charge carriers at the Fermi level. Based on this observation, we will propose relevantmechanisms for the MC in BaMn2Pn2’s and discuss the mechanisms from the viewpoint of
the symmetry and the orbital degree of freedom.
[1] Watanabe, H., Youichi Y., PRB 96, 064432 (2017)[2] Craco L., Carara S. S., PRB 97, 205114 (2018)[3] Huynh. K.K et al, PRB 99, 195111 (2019)

80

P-4

Increased Curie Temperature and Enhanced Perpendicular Magneto
Anisotropy of Cr2Ge2Te6/NiO Heterstructures
H. Idzuchi1-3*, A. E. Llacsahuanga Allcca3, X. C. Pan1, K. Tanigaki1, and Y. P. Chen1-4
1

WPI Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai
980-8577, Japan
Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
2
Center for Science and Innovation in Spintronics, Tohoku University, Sendai 980-8577,
Japan
3
Purdue Quantum Science and Engineering Institute and Department of Physics and4
School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue
University, West Lafayette, Indiana 47907, USA
Magnetism in two-dimensional van der Waals materials has received significant attention
recently. The Curie temperature reported for those materials, however, has been so far
remained relatively low. Here, we measure magneto-optical Kerr effects (MOKE) underperpendicular magnetic field for van der Waals ferromagnet Cr2Ge2Te6 as well as its
heterostructure with antiferromagnetic insulator NiO. We observe a notable increase in bothCurie temperature and magnetic perpendicular anisotropy in Cr2Ge2Te6/NiO heterostructurescompared to those in Cr2Ge2Te6. Measurements on the same exfoliated Cr2Ge2Te6 flake (on aSiO2/Si substrate) before and after depositing NiO show that the hysteresis loop can change
into a square shape with larger coercive field for Cr2Ge2Te6/NiO (Fig.1). The maximum Curie
temperature (TC) observed for Cr2Ge2Te6/NiO reaches ~120 K, is nearly twice the maximum
TC ~ 60 K reported for Cr2Ge2Te6 alone. Both enhanced perpendicular anisotropy andincreased Curie temperature are observed for Cr2Ge2Te6 flakes with a variety of thicknesses
ranging from ~5 nm to ~200 nm. The results indicate that magnetic properties of
two-dimensional van der Waals magnets can be engineered and controlled by using theheterostructure interface with other materials.
[1] H. Idzuchi, A. E. Llacsahuanga Allcca, X. C. Pan, K. Tanigaki and Y. P. Chen, Appl.
Phys. Lett. 115, 232403 (2019).

Fig. 1. MOKE curves for Cr2Ge2Te6 flake with and without NiO at various temperature.

81

P-5

Space-filling open microfluidics for droplet collection by hierarchicaltransport: generative design of fractal hyperbranched channels
Hiroyuki Kai1*
1

WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University

Open microfluidics enables controlled transport of liquid droplets on the solid surface.
Wettability patterning on the surface has been utilized to trap droplets and guide their transport.
Megaridis’ group developed an open microfluidic channel for the fast transport of aqueous
droplets using a narrow superhydrophilic strip with width gradient surrounded bysuperhydrophobic surface [1]. Their open microfluidic channel takes advantage of a coating ofa mixture of titanium oxide nanoparticles and Capstone® ST-100 fluoroacrylate copolymer,
which is originally superhydrophobic and turns superhydrophilic when irradiated withultraviolet (UV) light. This superhydrophilic microfluidic channel can be readily fabricated byphotolithography. We developed open microfluidic channels that collect aqueous liquid fromthe solid surface by directional transport and hierarchical fusion of droplets in hyperbranchedchannels [2]. Triangular regions that are filled with hyperbranched patterns of fractal geometry,called space-filling trees [3], were automatically generated by software with recursivealgorithm. Following the fabrication of photomasks with the generated patterns, the spacefilling open microfluidic channels were fabricated on a plastic film by photolithography. Whenfine water droplets were sprayed on the surface of the film, fast (< 1 s) and highly efficient(74% ± 9%) accumulation of water to a focal point at the center (a circle of 2mm radius) byrepeated transport and merging of the droplets in a hierarchical manner was observed. thealgorithms were developed to generate patterns of space-filling open microfluidic channels thatfill an arbitrary convex polygon, where the structural variation can be readily prepared byvarying a small number of parameters for the pattern-generating functions [4].

Figure 1: (a) Patterning algorithm of space-filling open microfluidics for an arbitrary
polygon and focal point in the case that the focal point is one of the vertices of thepolygon (b) Representative patterns, A (left), B (middle), and C (right). (c)Accumulated water blobs after spraying water droplets for the patterns A, B, and C.
[1] A. Ghosh et al., Lab on a Chip 14, 1538 (2014).
[2] H. Kai*, R. Toyosato, and M. Nishizawa*, RSC Adv. 8, 15985 (2018).
[3] J.J. Kuffner and S.M. LaValle, 2011 IEEE/RSJ International Conference on Intelligent
Robots and Systems (IROS), 2199–2206, 2011.
[4] H. Kai*, MicroTAS 2020.
Reproduced in part with permission from the Chemical and Biological Microsystems Society(CBMS). Copyright 2020 CBMS.”

82

P-6

Interface-Engineered Magnetic Gilbert Damping: An Experimental andInterface-Engineered
Gilbert Damping:
An Experimental
Theoretical StudyMagnetic
in Perpendicularly
Magnetized
Fe/MgAl22O44 andInterface-Engineered Magnetic Gilbert Damping: An Experimental andTheoretical Study in Perpendicularly
Magnetized Fe/MgAl2O4
Heterostructures
Theoretical Study in Perpendicularly
Magnetized Fe/MgAl2O4
Heterostructures
Heterostructures
1
1
1
1
1
1
R.
R. Mandal
Mandal1*,*, Q.
Q. Xiang
Xiang1,, K.
K. Masuda
Masuda1,, Y.
Y. Miura
Miura1,, H.
H. Sukegawa
Sukegawa1,, S.
S. Mitani
Mitani1 andand Y.
Y. K.
K.
1
1
1
11
1
1
TakahashiR.
Mandal
,
Y.
Miura
,
H.
Sukegawa,
S.
MitaniandY.
1 *, Q. Xiang
1 , K. Masuda
1111Takahashi
R. Mandal *, Q. Xiang , K. Masuda , Y. Miura , H.1 Sukegawa , S. Mitani and Y. K. K.
1Takahashi
Takahashi
11
ResearchCenterfor
MagneticandSpintronic
Research Center for Magnetic and Spintronic Materials,
Materials, National
National Institute
Institute forfor Materials
Materials
11
Science(NIMS),
Tsukuba
305-0047,
Japan
ResearchCenterfor
forMagnetic
MagneticandSpintronic
Materials,
National
Institutefor Materials
Research Center
Spintronic
Materials,
National
Institutefor Materials
Scienceand(NIMS),
Tsukuba
305-0047,
Japan
Science(NIMS),
Tsukuba
305-0047,
Japan
Science(NIMS),
Tsukuba
305-0047,
Japan

O

(b)

Keff (MJ m-3)

1.2

1.2
1.2

0.8

KeffK(MJ
Keff
(MJ
m-3)m
m-3-3))eff(MJ

1.2
0.8
0.8

0.4

0.8
(c)
0.4
00.4

(b)
(b)
(b)

O2 Vacancy

Excess O2

ExcessExcess O
O22
Excess O2

2

(d)

1.5

2
2

1

2
1.5
1.5

0.5

(MJ
m-3)m
m-3-3))
KeffK(MJ
Keff
eff(MJ

O
Al
O (a)

O
O22 Vacancy
Vacancy

Keff (MJ m-3)(a)0
Damping
Damping
Damping
Constant,
Constant,
Constant,
a aa
0 00
0.001
0.001
0.001 0.002
0.002
0.002

Al
O Mg
Al (a)

O2 Vacancy

Clean
Clean
Clean
Interface
Interface
Interface

Al Fe
Mg
(a)
Mg

0
0.01 0.02 0.03
Damping Constant, a
00 0.010.01
0.01
0.02
0.030.03
0.03 0.002
0 0.020.02
0.001

Fe
MgFe
Fe

Clean Interface

GilbertGilbert damping
damping isis oneone ofof thethe most
most unexploredunexplored issues
issues inin magnetic
magnetic materials,
materials, particularly
particularly in
in
[1-3]
[1-3]
Gilbertdamping
is
one
of
the
most
unexploredissuesinmagnetic
materials,
particularlyininterface-engineered
heterostructures.
A
recentcriticalissue
ofhigh-speed
andGilbertdamping
is
one
of
the
most
unexploredissuesinmagnetic
materials,
particularlyininterface-engineered heterostructures. A recent critical issue of high-speed
and
[1-3]
[1-3]
interface-engineered
heterostructures.
A
recentcriticalissue
ofhigh-speed
andenergy-efficient
spintronic
deviceslowdamping
interface-engineered
heterostructures.
A recentof
issue Gilbertof high-speed
andenergy-efficient
spintronic
devices isis coexistencecoexistence
ofcritical
low magnetic
magnetic
Gilbertdamping constantconstantenergy-efficient
spintronic
devicesis iscoexistenceof low
magnetic
Gilbertdamping
constant
(α)
and
large
perpendicularmagnetic
anisotropy(PMA).
To
investigate
both
in
a
model
energy-efficient
spintronic
devicescoexistenceoflowmagnetic
Gilbertdamping
constant(α) and large perpendicular magnetic anisotropy (PMA). To investigate both in a model(α) andand experimentallylargemagnetic(PMA).
To investigate
bothinbeena modelsystemandtheoretically,a flat,flat, lattice-matchedlattice-matchedhas(α)
large perpendicularperpendicularmagneticanisotropy
anisotropy(PMA).
To interface
investigate
bothindeveloped
a modelsystemexperimentally
andtheoretically,ainterfacehas
beendeveloped
system experimentally and theoretically, a flat, lattice-matched interface has been developed
in
an
Fe
(0.7
nm)/MgAlO(3nm)
epitaxial
bi-layerfilm
byvaryingtheex-situannealingsystemexperimentally
andtheoretically,aflat,
lattice-matchedinterfacehas
beendeveloped
24
in(0.7 nm)/MgAlnm)/MgAl
2O4 (3 nm) epitaxial bi-layer film by varying the ex-situ annealing
in an
an Fe
Fe (0.7
2O4 (3 nm) epitaxial bi-layer film by varying the ex-situ annealing
temperature,
is
main
vary
the
interfacedegreePMA
energyin an Fe (0.7whichnm)/MgAl
O4catalyst(3 nm) to
epitaxial
bi-layerfilmoxidation
by varying
the andex-situannealing
temperature,
which
is
main
catalyst
varyinterfaceoxidation
degreeandPMA
temperature, which is main2 catalyst
to to
vary
thetheinterfaceoxidation
degreeand PMA
energyenergy
densities.
Here,
the
optimized
procedureforinterfaceengineering
allowstoachievethetemperature,
which
is
main
catalyst
to
vary
the
interfaceoxidation
degreeandPMAdensities.
Here, thethe optimized
optimizedprocedure
procedureinterfaceengineering
allowsto achieve
thedensities. Here,forforinterfaceengineering
allowsto achieve
the–3energy–3). thelowestα(0.013)everreported
andastronginterfacial
PMA
energy(0.8
MJm–3
densities.
Here,
the
optimized
procedureforinterfaceengineering
allowstoachievelowest(0.013) evereverreported
reportedandanda strong
a strong
interfacial
PMA
energy). By
By
lowest αα (0.013)
interfacial
PMA
energy(0.8 (0.8
MJ mMJ). m
By–3
employingdifferentinterfacial
atomicconfigurations
inafirst-principles
calculation,thelowestα(0.013)everreported
andastronginterfacial
PMA
energy
(0.8
MJ
m
).
By
employingdifferent interfacialinterfacialatomic
atomicconfigurations
configurations
a first-principles
calculation,
employing different
in ainfirst-principles
calculation,
the theoriginofthePMA
energy
and
α
has
been
explained.
The
d(yz)
and
d(zx)
orbitalsofemployingdifferentinterfacial
atomicconfigurations
inafirst-principles
calculation,
theorigin of thebeen
explained.
TheThed(yz)d(yz)and andd(zx)d(zx)orbitalsof theof theoriginthe PMA
PMA energy
energyandandα αhashas
been
explained.
orbitalsinterfacial
Fe
atoms
in
the
minority-spinstatesareresponsible
forandorbitalits
originof thePMA
energyandα has been
explained.
The d(yz)d(zx)moment
orbitalsof theinterfacialFe
statesare areresponsible
for orbital
momentand itsand
interfacial
Fe atoms
atomsininthe
theminority-spinminority-spinstatesresponsiblefororbitalmomentanditsanisotropy.
Furthermore,thematrixelements
betweenthese
twoorbitalsinthenon-spin-flip
interfacial
Fe
atoms
in
the
minority-spinstatesareresponsiblefororbitalmomentanditsanisotropy.
Furthermore,thematrixelements
betweenthese
twoorbitalsinthenon-spin-flip
anisotropy. Furthermore, the matrix elements between these two orbitals in the non-spin-flip
term predominately
predominately
contributedamping.
These
detailed
findings
providea clearinsight
into intoterm
contributetodamping.
These
detailed
findings
provideclear
insight
anisotropy.
Furthermore,
the tomatrixelements
betweenthese
twoorbitalsinaa thenon-spin-flip
term
predominately
contributetodamping.
These
detailed
findings
provideclear
insight
intothedevelopmentofmaterials
withstrongPMA
energiesandlowdampingcharacteristics,
thedevelopmentofmaterials
withstrongPMA
energiesandlowdampingcharacteristics,
term
predominately
contributetodamping.
These
detailed
findings
provideaclear
insight
into
the development of materials with strong PMA energies and low damping characteristics,
therebyfacilitatingpromisingfuturespintronic
applications.
therebyfacilitating
futurespintronic
applications.
the development
materialsfuturewith spintronicstrong PMA
energies and low damping characteristics,
therebyfacilitatingofpromisingpromisingapplications.
thereby facilitating promising future spintronic applications.
[1] S. S.
S. P.
Parkin, C.
Kaiser,A. Panchula,P. M. M.
Rice, B. Hughes,
M. Samant,
S.-H. Yang, Yang,
[1]
P.
C.
Kaiser,[1] S.
S.Nat.
S. Mater.
P. Parkin,
Parkin,C.(2004).
Kaiser, A.
A. Panchula,
Panchula, P.
P. M. Rice,
Rice, B.
B. Hughes,
Hughes, M.
M. Samant,
Samant, S.-H.
S.-H. Yang,
3,
862
Nat.
Mater.
3, 862862(2004). A. Panchula, P. M. Rice, B. Hughes, M. Samant, S.-H. Yang,
[1]
S.
S.
P.
Parkin,C.
Kaiser,Nat.
Mater.
3,(2004).
[2] S. Ikeda, K. Miura, H. Yamamoto, K. Mizunuma, H. D. Gan, M. Endo, S. Kanai, J.
[2] S.
Ikeda,K.
H.
Yamamoto,K.
Mizunuma,H.
Nat.
Mater.
862 (2004).
[2]
S.
Ikeda,
K.F.3,Miura,
Miura,H. H.
Yamamoto,
Mizunuma,
H. D.
D. Gan,Gan, M.
M. Endo,Endo, S.
S. Kanai,
Kanai, J.
J.
Hayakawa,
Matsukura,Ohno, Nat.K.
Mater.
9, 721 (2010).
Hayakawa,
F.
Matsukura,
H.
Ohno,
Nat.
Mater.
9,721(2010).
[2]
S.
Ikeda,K.
Miura,H.
Yamamoto,K.
Mizunuma,
H.
D.
Gan,
M.
Endo,
S.
Kanai,J.
Hayakawa,
F.
Matsukura,
H.
Ohno,
Nat.
Mater.
9,721(2010).
[3] L. Berger, Phys. Rev. B 54, 9353 (1996).
[3]
L.
Berger,
Phys.
Rev.
B
54,
9353
(1996).
Hayakawa,
F.
Matsukura,
H.
Ohno,
Nat.
Mater.
9,721(2010).
[3] L. Berger, Phys. Rev. B 54, 9353 (1996).
[3] L. Berger, Phys. Rev. B 54, 9353 (1996).

1.5
1
1

1
0
0.5
0.5
650 700 750
-2
-1
0
1
0.4
(d)
(c)
(d) at the interface 0.5
No. of O atoms
Tannl (K)
(c)
0
0
0
0
600
700
750
-2
-1
0
1
(c) 650600
650
700
750 [001] (d)-2-1
0 with1 (a) oxygen-poor and (b)Fig. 1. Schematic of the Fe/MgAl
O(MAO)
interfaces
2400
No. ofof-2O
O atoms
atoms
at 0thethe interface
interface(K)
Tannl (K)600 650700 750
-1 at
1
No.
T
600

oxygen-rich (b) interfaces. The
experimental and calculated magnetic Gilbert damping
annl

No.
of O atoms
at theinterfaceTannl2(K)a andmagnetic
anisotropy(PMA)
energyis plotted as andaFig.
Schematicof
Fe/MgAl[001]
interfaces
with
(a)
(b)
Fig. 1.
1. constant
Schematicof thethe perpendicular
Fe/MgAlO44 (MAO)
(MAO)
[001]
interfaces
with(a) oxygen-poor
oxygen-poor
and
(b)
2O
of
the
annealing
temperature
T
(c)
and
numberofoxygenatoms,
n
at
the
annl
O
oxygen-rich(b)interfaces.
The
experimental
andcalculated
magnetic
Gilbertdamping
Fig. 1. function
SchematicoftheFe/MgAl
O
(MAO)
[001]
interfaces
with(a)oxygen-poorand(b)
2 4 experimental and calculated magnetic Gilbert damping
oxygen-rich (b) interfaces. Theinterface(d).
constantaandtheperpendicularmagnetic
anisotropy(PMA)
energyisplottedasoxygen-rich(b) interfaces.
The experimental
and calculated
magnetic
damping
constanta andthe perpendicularmagnetic anisotropy(PMA)
energyGilbertis plotted
as aafunctionthetemperature
TandofnnOO atconstant ofa andthe perpendicularmagnetic
anisotropy(PMA)
energyatoms,
is plottedfunctionofthe annealing
annealing
temperature
Tannl
(c)
and number
numberof oxygenoxygenatoms,
atasthetheaannl (c)interface(d)..
function of
annealing temperature Tannl (c) and number of oxygen atoms, nO at theinterface(d)the83
interface (d).

P-7

Atomic-layered antiferromagnet with perpendicular magnetic anisotropy
K. Z. Suzuki1,2, and S. Mizukami1,2,3
1

2

WPI Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
Center for Spintronics Research Network (CSRN), Tohoku University, Sendai, Japan
3
CSIS (CRC), Tohoku University, Sendai, Japane-mail: kazuya.suzuki.d8@tohoku.ac.jp

Recently, an antiferromagnet has attracted much attention in spintronics [1]. Because theirzero net magnetization and strong exchange coupling are distinct from conventional
ferromagnet, thus, it is expected to be promising material for future spin-torque devices.
Recently, we found that an atomic-layered antiferromagnetic Mn grown on a CoGa seed layer
exhibits perpendicular anisotropy. In addition, a magnetic tunnel junctions utilizing
atomic-layered Mn shows clear tunnel magnetoresistance (TMR) effect at room temperature[2]. In this poster presentation, we report structural (Fig.1) and magnetic properties (Fig.2)
and TMR effect of MTJs using atomic-layered Mn electrode. Moreover, we demonstrate theelectrical switching of their magnetization by spin-orbit torque.

Refference[1] T. Jungwirth et al., Nat. Nanotechnology 11, 231 (2016)[2] K. Z. Suzuki et al. ACS Appl. Mater. Interfaces 10, 43305 (2018)

Fig.1 The cross-sectional HAADF-STEM
image of the CoGa/Mn/MgO layers.

Fig.2 Anomalous Hall effect of the
CoGa/Mn/MgO structure.

84

P-8

Turbulent Mixing Phenomenon and Solvent Effects on Kinetics ofSupercritical Hydrothermal Synthesis: Reaction of Nickel Nitrate to Nickel
Oxide
Akira Yoko1, Gimyeong Seong2, Takaaki Tomai3, Tadafumi Adschiri*1,2,3
1

WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University
New Industry Creation Hatchery Center, Tohoku University, Sendai 980-8579, Japan
3
Institute of Multidisciplinary Research for Advanced Materials, Sendai 980-8577, Japan,*Email: akira.yoko.c7@tohoku.ac.jp
2

Reaction kinetics of hydrothermal synthesis for the nickel nitrate to nickel oxide that occurs ina wide range of temperatures and pressures around the critical point of water was evaluated.
The effects of mass transfer on the reaction rate were evaluated using a two-flow mixing
system. The mixing rate, which affects reaction kinetics was successfully described using Re
number and temperature. The kinetics under reaction control conditions was obtained basedon the mixing study. The hydroxyl ion concentration, which varies greatly around the criticalpoint, strongly affects the reaction kinetics. Results suggest that the hydroxyl ion is a reactantof the hydrothermal reaction. With consideration of that fact, the intrinsic reaction constantwas evaluated to understand the solvent effects. Near the critical point, the properties of waterchange greatly with even slight changes of temperature and pressure. Strong solvent effects
on the intrinsic kinetic constant were observed. An acceleration of intrinsic kinetics above thecritical temperature or with reduced pressure in a supercritical condition is attributable to adecrease in the dielectric constant. This dielectric constant effect on the intrinsic rate constantfrom gas-like to liquid-like atmospheres can be explained well using the Kirkwood equation,
which suggests a missing link between Eyring’s gas-phase absolute kinetics theory and the
Kirkwood liquid phase solvent effect theory.
[1] A. Yoko, Y. Tanaka, G. Seong, D. Hojo, T. Tomai, T. Adschiri, J. Phys. Chem. C 124 (8),4772–4780 (2020).

Fig. 1. Solvent effects around critical point [1].

85

P-9

Nonreciprocal
Nonreciprocal Electronic
Electronic Transport
Transport inin an
an Itinerant
Itinerant Antiferromagnet
Antiferromagnet
120-degree
Spin
Structure
2 withNonreciprocal PdCrO
Electronic
Transport
in anItinerant
Antiferromagnet
PdCrO
120-degree
Spin
Structure
2 withPdCrO2 with
120-degree
Spin
Structure*
M.
M. Akaike
Akaike*,, Y.
Y. Nii,Nii, H.
H. Masuda
Masuda andand Y.
Y. Onose
Onose*
M. Akaike , Y. Nii, H. Masuda and Y. Onose
Institute
Institute forfor Materials
Materials Research,
Research, Tohoku
Tohoku University
University
Institute for Materials Research, Tohoku University

Non-collinear
Non-collinear magnets
magnets have
have attracted
attracted much
much attention
attention due
due toto itsits non-trivial
non-trivial magnetic
magnetictransport.
It
can
be
causedbyanemergent
field
owing
to
the
complexspin
arrangements.
In
transport.
It can becaused by
an attracted
emergent muchfield owing
to thecomplexarrangements.
In
Non-collinear
magnetshaveattentiondue
to its spin
non-trivial
magneticorder
toelucidatethemechanism,
thepreciseunderstandingofthemagnetic
structureisorder to elucidate
mechanism,
the precise
understandingof the magnetic
structure In
istransport.
It can be thecausedby an emergent
field owing
to the complex
spin arrangements.
essential.
While thethetheneutrondiffraction
measurements
should playplay
significant
role, somesomeessential.
While
neutrondiffraction
measurements
shouldaa significant
role,
order
to elucidate
mechanism,
the precise
understandingof themagnetic structureisprobessensitivetosymmetrybreakings
canalso
providevaluable
information
andhelp
probes sensitive
to symmetry
breakingsmeasurements
can also provide
informationrole,and some
help
essential.
While theneutron diffraction
shouldvaluable
play a significant
identify sensitive
accurateto spin
spin
structures.
We canstudyalsothetheprovide
magnetic
structurein an
an anditinerant
identify
accuratestructures.
We
study
magnetic
structureinitinerant
probessymmetrybreakings
valuable
information
help
antiferromagnet
PdCrO
utilizing
nonreciprocal
electronictransport,asymmetry-sensitive
antiferromagnet
utilizing nonreciprocaltransport,
a symmetry-sensitive
identify accuratePdCrO
spin22 structures.
We study electronic
the magnetic
structurein an itinerant
probe.
probe.
antiferromagnet PdCrO2 utilizing nonreciprocal electronic transport, a symmetry-sensitive
Generally
Generally speaking,speaking, inin thethe spatial
spatial inversion
inversion andand time-reversal
time-reversal symmetries
symmetries simultaneously
simultaneously
probe.
brokensystems,theresponses
forrightward
andleftward
stimuliaredifferent
frombrokensystems,theresponses
forrightward
andleftward
stimuliaredifferent
from each
each
Generally speaking, in the spatial inversion and time-reversal symmetries simultaneously
other.
The
nonreciprocal
electronictransport
iselectricalresistivity
depending
on
the
sign
of
other. The
nonreciprocal
electronic
electricalresistivity
on theofbrokensystems,
the responses
for transport
rightwardisand
leftward
stimuli depending
are different
fromsign
eachelectric
current[1].
electricThecurrent[1].
other.
nonreciprocal
electronic transport is electrical resistivity depending on the sign ofIn
2, the magnetic moments show the 120-degree structure below TN = 37 K. The
In PdCrO
PdCrO
electric
current[1].magnetic moments show the 120-degree structure below TN = 37 K. The
2, theunconventionalHall
proposedtotheis
unconventional
anomalous
Hall effecteffectproposed
to be
be induced
inducedbythe Tspin-chirality
spin-chirality
ismagnetic momentsshow
the 120-degree
structure by
below
In PdCrO2, theanomalous
N = 37 K. The
observedatlowtemperatures[2].
To
examinetheinteresting
spin-chirality
scenario,
preciseobserved
at low anomalous
temperaturesHall[2]. effect
To examine
the interesting
spin-chirality
preciseunconventional
proposed
to be inducedby the scenario,
spin-chirality
isinformationof 120-degree
120-degree
structuressuch
as interlayerinterlayer
couplings
is indispensable.
indispensable.
Apreciserecentinformationofstructuresascouplings
isrecentobserved
at lowtemperatures[2]. To suchexaminethe interesting
spin-chirality
scenario,Aneutron scattering
scattering
analysis structures
proposed suchthe staggered
staggeredchirality
structure[3]. It
It meansmeansAthat
that
theneutronanalysis
proposedthechirality
structure[3].
theinformationof 120-degree
as interlayer
couplings
is indispensable.
recentchiralities
of
each
even
and
odd
layersareoppositetoeachother.
chiralitiesscatteringof each evenand odd
layers theare staggered
opposite tochirality
each other.
neutronanalysis
proposedstructure [3]. It means that theHere, we
wefabricatemicroscopic
device(Fig.
1(a))other.
and observe
observe thethe nonreciprocal
nonreciprocal
Here,fabricateaa microscopic
device
(Fig.
1(a))
and
chiralitiesof eacheven andodd layers areoppositeto eachelectronictransport.
As shown
shown
in Fig.
Fig. 1(b),1(b),
we havehave
found
theandfinitenonreciprocity
below thetheelectronictransport.
Asin
we
finitenonreciprocity
below
Here, wefabricatea microscopic
device(Fig.found1(a))theobservethe nonreciprocalNeeltemperature.
It
indicates
thebreakingofthespatialinversion
symmetryinthein theNeeltemperature.
the 1(b),breakingof thespatialinversion
symmetryelectronictransport. ItAsindicatesshown in Fig.
we havefound
the finite
nonreciprocity
below
antiferromagnetic
state.
Inthe
poster,we
will
discuss
possiblespin
structures
based
on
the
antiferromagnetic
In the poster,we will discussspin structures
based inon theNeel temperature.state.
It indicatesthe breakingof the possible
spatial inversion
symmetry
detailedmagnetic field
field
dependenceof nonreciprocal
nonreciprocal
electronictransport.
detailedmagnetic
ofelectronic
antiferromagnetic
state.dependence
In the poster,we will discusspossibletransport.
spin structures based on thedetailed magnetic field dependence of nonreciprocal electronic transport.
[1] Y.
Y. Tokura,
Tokura, andand N.
N. Nagaosa,
Nagaosa, Nature
Nature Communications
Communications 9,9, 3740
3740 (2018).
(2018).
[1][2]
H.
Takatsu,S.
Yonezawa,
S.
Fujimoto,andY.
Maeno,
Phys.
Rev. Lett.
Lett. 105,
105, 137201
137201[2]
H. Tokura,
Takatsu,and
S. N.
Yonezawa,
S. Fujimoto,and Y. Maeno,
Phys.
Rev.
[1] Y.
Nagaosa, Nature
Communications
9, 3740(2018).
(2010).
(2010).
[2] H.
Takatsu, S. Yonezawa, S. Fujimoto, and Y. Maeno, Phys. Rev. Lett. 105, 137201[3] H.
H.
Takatsu, G.
G. Nénert,
Nénert, H.
H. Kadowaki,
Kadowaki, H.
H. Yoshizawa,
Yoshizawa, M.
M. Enderle,
Enderle, S.
S. Yonezawa,
Yonezawa, Y.
Y. Maeno,
Maeno,[3]
Takatsu,(2010).
J.
Kim,
N.
Tsuji,
M.
Takata,Y.
Zhao,
M.
Green,
andC.
Broholm,
Phys.
Rev.
B89,
J. Takatsu,
Kim, N.G.
Tsuji,M. H.
Takata,Y. Zhao,M. Green,M.and
C. Broholm,
Phys. Y.
Rev.
B89,
[3] H.
Nénert,Kadowaki,
H. Yoshizawa,
Enderle,S. Yonezawa,
Maeno,
104408(2014).
104408
J. Kim, (2014).
N. Tsuji, M. Takata, Y. Zhao, M. Green, and C. Broholm, Phys. Rev. B89,
104408 (2014).

Fig.
Fig. 1.
1. (a)(a) SEMSEM image
image ofof thethe sample
sample device.
device.
(b) SEM
Temperaturedependenceofaveraged nonreciprocal
nonreciprocal electronic
electronic transporttransport inin H⊥j.
H⊥j.
(b)
Temperature
averaged
Fig. 1. (a)image ofdependence
the sample ofdevice.
(b) Temperature dependence of averaged nonreciprocal electronic transport in H⊥j.
86

P-10

Epitaxial L10-FeNi Films with a High Degree of Order and Uniaxial
Magnetic Anisotropy Fabricated by a Denitriding Method
Keita Ito1,2, Masahiro Hayashida1, Takumi, Ichimura1, Takahiro Nishio3, Sho Goto3,
Hiroaki Kura3, Tomoyuki Koganezawa4, Masaki Mizuguchi5, Yusuke Shimada1,
Toyohiko J. Konno1, Hideto Yanagihara6, and Koki Takanashi1,2,7
1

Institute for Materials Research, Tohoku University, Japan
Center for Spintronics Research Network, Tohoku University, Japan
3
Advanced Research and Innovation Center, DENSO CORPORATION, Japan
4
Japan Synchrotron Radiation Research Institute, SPring-8, Japan
5
Department of Materials Process Engineering, Nagoya University, Japan
6
Department of Applied Physics, University of Tsukuba, Japan
7
Center for Science and Innovation in Spintronics, Core Research Cluster,
Tohoku University, Japan
2

Ferromagnetic materials possessing large uniaxial magnetic anisotropy energy (Ku) andcomposed of earth abundant elements are required in order to realize the next-generation
permanent magnets. We have focused on the L10-ordered FeNi alloy as a rare-earth free highKu ferromagnetic material [1]. Recently, the synthesis of polycrystalline L10-FeNi powder bydenitriding FeNiN powder was reported, and a degree of order (S) of 0.71 was achieved [2].
However, the exact Ku value of L10-FeNi formed by the denitriding method is still unclear,and the evaluation of Ku using a single-crystal L10-FeNi is required. In this study, we grew
epitaxial FeNiN films by molecular beam epitaxy and fabricated L10-FeNi films by nitrogen
topotactic extraction, and characterized their S and Ku values.
20 nm-thick FeNiN films were grown on SrTiO3(001) substrates at 200, 250, and 350 °C
by supplying Fe, Ni, and radio-frequency N2 plasma, simultaneously [3]. Denitriding was
performed by ex-situ furnace annealing at 300 °C for 4 h under an H2 gas flow rate of 1 L/min
at ambient pressure. Structure of the samples was characterized by x-ray diffraction
measurements using Cu-Kα radiation and synchrotron radiation (hν = 7.11 keV), andcross-sectional scanning transmission electron microscope (STEM) measurements.
Magnetization curves were measured by vibrating sample magnetometer at room temperature,and the Ku value was estimated by magnetic torque measurements.
The epitaxial L10-FeNi films oriented with the a-axis perpendicular to the film plane
having two variants with the orthogonal in-plane c-axes are fabricated. For the sample grown
at 350 °C, the S and Ku values are evaluated to be 0.87 and 5.9 × 105 J/m3, respectively. In
spite of the large S value exceeding those reported previously [1,2], the Ku value is modestly
high. The exchange length of L10-FeNi (3.2 nm) is comparable to the variant sizes of oursamples estimated by the STEM measurements. This strongly suggests that the obtained
macroscopic Ku value is smaller than the actual Ku of each variant [4].
This work was supported by the Future Pioneering Program “Development of magnetic
material technology for high-efficiency motors” (Proposal No. JPNP14015) commissioned by
the New Energy and Industrial Technology Development Organization, Japan. The
synchrotron radiation XRD was conducted at the BL46XU of SPring-8 with the approval of
JASRI (Proposal No. 2019A1802).
[1] K. Takanashi et al., J. Phys. D: Appl. Phys. 50, 483002 (2017).
[2] S. Goto et al., Sci. Rep. 7, 13216 (2017).
[3] K. Ito et al., J. Magn. Soc. Jpn. 43, 79 (2019).
[4] K. Ito et al., Appl. Phys. Lett. 116, 242404 (2020).

87

P-11

Chirality memory stored in magnetic domain walls in the ferromagnetic
state of MnP
N. Jiang1, Y. Nii2,3, H. Arisawa2, E. Saitoh2,4,5,6, and Y. Onose2
Department of Basic Science, The University of Tokyo1,
Institute for Materials Research, Tohoku University2,
PRESTO, Japan Science and Technology Agency 3,
Department of Applied Physics, The University of Tokyo4
Advanced Science Research Center, Japan Atomic Energy Agency5
Advanced Institute for Materials Research, Tohoku University6

Chirality is a lack of mirror symmetry in matter. In the human body, somemolecules, such as amino acids, are homo-chiral, meaning that they show only
one certain chiral state. In biology, it is important to elucidate how chiralinformation is transferred and memorized.
Chirality also appears in magnetic structures. One example is a helical magnetic
structure, in which the ordered direction of the magnetic moment spatially rotatesin a plane perpendicular to the propagation vector. The sense of rotation isreversed by any mirror operation and therefore determines the chiral state. Similarmagnetic chirality shows up in a Bloch-type domain wall (DW) in ferromagnets.
The magnetic moment rotates on the domain wall, and the sense of rotation is
responsible for the chirality, similarly to helimagnets. We report the transfer ofchiral information from a helical magnetic structure to a ferromagnetic DW during
a helimagnetic to ferromagnetic phase transition in an itinerant helimagnet MnP.
ଶ୤
The 2nd harmonic resistivity ߩୟୱ୷୫
, which reflects the breaking down of mirror
symmetry, was found to be almost unchanged after heating the sample above theferromagnetic transition temperature and cooling it back to the helimagnetic state.
The application of a magnetic field along the easy axis in the ferromagnetic state
quenched the chirality-induced 2nd harmonic resistivity. This indicates that thechirality memory effect originated from the ferromagnetic domain walls[1].

ଶ୤୤Fig. 1. Magnetic field dependence of ߩୟୱ୷୫
at 52 K at the initial state (circles), that after
annealing at 80 K (triangles), and that after annealing at 80 K and application of 1ଶ୤
was positive (݆୮ ‫צ‬T magnetic field along the c-axis (squares). The initial ߩୟୱ୷୫
‫ܪ‬୮ ) and negative (݆୮ ‫ צ‬െ‫ܪ‬୮ ) in (a) and (b), respectively.

[1] N. Jiang, Y. Nii, H. Arisawa, E. Saitoh, and Y. Onose, arXiv:2010.02491 (2020).

88

P-12

Transparent CaHfO3 crystals synthesized by the Core Heating method
Yutaro Kurashima1, Shunsuke Kurosawa1,2, Rikito Murakami1,3, Akihiro Yamaji1,2, Kei
Kamada1,2,3, Masao Yoshino1, Satoshi Toyoda1,2, Hiroki Sato1,2, Yuui Yokota1, Yuji
Ohashi1,2, Takashi Hanada1, Akira Yoshikawa1,2,3
1

2

Tohoku Univ. IMR, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
Tohoku Univ. NICHe, 6-6-10 Aramaki-aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8579,
Japan
3
C&A corp., 1-15-9 Ichibancho, Aoba-ku, Sendai, Miyagi 980-0811, Japan

Scintillators are used in medical imaging such as positron emission tomography. The
gamma-ray stopping power is one of the most important properties of scintillators, and thepower is proportional to the effective atomic number to the 4-5. Hf compounds like Ce doped
CaHfO3, SrHfO3 and BaHfO3[1] are attractive scintillator materials with high effective atomic
numbers. However, the crystal growth of Hf compounds by the conventional crystal growthmethod has been not suitable and material search is not advanced. This is because Hf
compounds typically have a much high melting point (melting point of SrHfO3: ~2730°C).
For material search of Hf compounds with a high melting point, we have developed a novel
crystal growth method using electric arc, “Core Heating (CH) method”. The CH method canbe applied for the material search of high melting point materials due to fast growth time, lessraw materials (a few g) and no crucibles. As a first demonstration of crystal growth of Hf
based scintillation materials by the CH method, we grew transparent Ce-doped CaHfO3
crystals. Ce-doped CaHfO3 has a relatively high effective atomic number and lower melting
point than other Hf compounds like SrHfO3.
Ce-doped CaHfO3 samples were synthesized by the
CH method in the first time. We placed raw material
powder and an iridium tablet on Cu hearth. The iridium
tablet was melted by the electric arc and raw material
powder was melted by melted iridium. After that, we
gradually weakened the output of the electric arc and we
got transparent Ce-doped CaHfO3 crystals. Synthesized
crystals were cut and mirror polished, and samples wereprepared.
We succeeded in the growth of the transparent
Ce-doped CaHfO3 crystals synthesized by the CH method
Fig. 1. Photograph offirst time. Figure 1 shows a photograph of transparent
transparent Ce-doped
Ce-doped CaHfO3 crystal synthesized by the CH method.
CaHfO
3 crystal synthesized
The crystals were confirmed as a single phase (CaHfO3)
by
the
CH
methodusing X-ray diffraction. Some optical and scintillation
properties were measured such as transmittance,
photo-luminescence spectra, light output, and scintillation decay time. For instance, thetransmittance was approximately 54% and the scintillation decay time component wasapproximately 22 ns. This sample was found to have fast decay time than conventional
scintillators.
[1]

S. Kurosawa, J. Pejchal, S. Wakahara, et al., Radiat. Meas. 56 (2013) 155–158.

89

P-13

Study on the bandgap structure for Ce:(La, Gd)2Si2O7 scintillators
S. Kurosawa, Y. Shoji, R. Murakami, T. Horiai, A. Yamaji, A. Yoshikawa
Institute for Materials Research (IMR) & New Industry Creation Hatchery Center (NICHe),
Tohoku University
Recently, the pyrochlore crystals described with an A2Si2O7 formula, have been studied as
scintillation materials, where the A is(are) rare-earths. The Gd2Si2O7 (GPS), Lu2Si2O7 (LPS)
Ce:(Gd, La)2Si2O7 (Ce:La-GPS) have been investigated with good light outputs or energy
resolutions [1-4]; The light outputs were estimated to be over 30,000 photons/MeV [5]. Also,
good scintillation properties were found to be stable up to 450 K, as has been reported earlier
for Ce:LPS and Ce:La-GPS crystals. Although Ce:LPS cannot be applied to oil well logging
due to its intrinsic background, Ce:La-GPS can be.
The temperature dependence was found to be related to the bandgap energy and defectlevel; generally, a sample with large energy-deference between the bottom of conduction bandand 5d level of Ce3+ (hereafter, we describe “5d-conduction band”) can maintain the light
output at even high temperature. In this paper, we evaluated scintillation properties and theirbandgap structure including the 5d-conduction band for Ce:La-GPS materials.
Ce:(Gd1-x Lax)2Si2O7 crystals were grown by the micro-pulling down method andCzochralski (Cz) process Moreover, Ce:Gd2SiO5 which is one of the conventional materials
for oil well logging was prepared. The bandgap energies were estimated from transmittancespectra at 5 K using synchrotron faculty named Ultraviolet Synchrotron Orbital Radiation
Facility (UVSOR) in Japan. 5d-conduction band was evaluated with photon- stimulated
luminescence. Some traps were estimated by the thermo-luminescence technique.
The bandgap energies for Ce:(Gd, La)2Si2O7 were large values (~ 7.1 eV) than that ofconventional scintillation materials such as Ce:Gd2SiO5 The results showed that the energy
gap between the Ce3+ 4f- level (2F5/2) to bottom of the conduction band is estimated ~4.2 eV,
and the gap of 4f – 5d was evaluated to be 3.2 eV from emission spectrum data. Thus, the5d-conduction band was calculated to be 1.0 eV. Moreover, we confirm the energy using
other methods, vacuum referred binding energy.
The 5d-conduction band energy of Ce:La-GPS was similar to conventional scintillators (i.e.
Ce:Lu3Al5O12 :1.07 eV, Ce:Y3Al5O12: 1.05 eV). Thus, we found some defect(s)/traps can be
rated to the temperature dependence. Thermo-luminescence glow curves of Ce:La-GPS andCe:Gd2SiO5 (Ce:GSO), and Ce:La-GPS had small number of traps than Ce:GSO. In thispaper, we show the band gap structures for these samples and the mechanism of thermal
quenching for these samples.
[1] S. Kawamura, et al , in IEEE Nuclear Scie. Symp. Conf. Rec. 2006, pp.1160-1163(2006).
[2]S. Kawamura, et al. NIMA583, 356 (2007).
[3]J. H. Kaneko, et al. , NIMA529, 307 (2004).
[4]L. Pidol,et al. IEEE TNS 51, 1084 (2004).
[5] A. Suzuki, S. Kurosawa, and A. Yoshikawa et al., Appl. Phys. Express 5, 102601(2012).

90

P-14

Hydrogen-assisted Damage Evolution in Nitrogen-doped Duplex Stainless
Steel
Milene Yumi Maeda1,2*, Motomichi Koyama1,3, Hayato Nishimura1,4, Osvaldo Mitsuyuki
Cintho2 and Eiji Akiyama1
1

Institute for Materials Research (IMR), Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai
980-8577, Japan
2
Materials Engineering Department, State University of Ponta Grossa, Av. Gen. Carlos
Cavalcanti, 4748, Uvaranas, Ponta Grossa, Paraná, 84030-900, Brazil
3
Elements Strategy Initiative for Structural Materials (ESISM), Kyoto University,
Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
4
Department of Quantum Science and Energy Engineering, Graduate School of Engineering,Tohoku University, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi, Japan

Duplex stainless steels are multiphase steels, whose microstructure consists of ferrite andaustenite. The use of duplex steels is increasing because they present corrosion resistancecoupled with superior mechanical properties and weldability [1–3]. Additionally, they havelower Ni contents in their composition, which lowers their cost and turn them into attractive
replacement options for austenitic stainless steels. Furthermore, high-strength duplex stainlesssteels have been developed through nitrogen doping and grain refinement [4–6]. As duplex
stainless steels have been used as structural materials in chemical, petrochemical, marine andoil and gas industries [1,7], the effects of hydrogen on their mechanical properties arepractically important.
In this work, the effects of hydrogen on ductility loss and fracture behavior of a nitrogen
doped duplex stainless steels are investigated via tensile testing after electrochemicalhydrogen pre-charging. Hydrogen pre-charging drastically decreased the steel ductility, but
the strength was increased at some extent, attributed to the solid solution hardening.
Post-mortem microstructure analyses were performed to characterize the microstructural
damage evolution and fracture surface. Hydrogen charging of the steel resulted inquasi-cleavage and intergranular fractures, which were associated with transgranular austenite
cracking and ferrite/austenite interface cracking, respectively. The hydrogen was observed toassist occurrence of deformation twinning in austenite. The crucial factors that resulted inbrittle-like cracking were deformation twinning in austenite and nitrogen-related solution
hardening.
[1]
[2]
[3]
[4]
[5]
[6]
[7]

Gunn RN, Acmm, 45, 2, 12845bae.001 (1998).
Andersson J-O, Alfonsson E, Canderyd C, Groth HL, Proc Stainl. Steel World Conf,(2010).
Canderyd C, Pettersson R. Int Corros Conf Ser, 5, 4081–90 (2012).
Chou SL, Tsai WT, Mater Sci Eng A, 99, 00174-4 (1999).
Lo KH, Shek CH, Lai JKL, Mat Sci Eng R, 65, 03.001 (2009).
Knyazeva M, Pohl M, Structure. Metallogr Microstruct Anal, 2, 00668 (2013).
Azevedo CRF, Pereira BH, Wolynec S, Padilha AF, Eng Fail Anal, 97, 12.009 (2019)

91

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Effects of Residual Stress on Hydrogen Embrittlement of a Stretch-Formed
Tempered Martensitic Steel Sheet
Hayato Nishimura1, 2, Tomohiko Hojo1, Hiroyuki Saito3, and Eiji Akiyama2
1 Institute for Materials Research, Tohoku University (IMR)
2 Graduate School of Engineering, Tohoku University

3 National Institutes for Quantum and Radiological Science and Technology

The strength of automotive frame parts has increased for improvements in impact safety andlight-weighting. However, when the tensile strength of the high-strength steel exceeds morethan 1 GPa, hydrogen embrittlement becomes a critical issue [1]. Besides, we have to consider
the effects of residual stress and plastic strain, which are introduced by press-forming, onhydrogen embrittlement properties when high-strength steels are applied for automotive
structural parts. In this study, the effects of residual stressand plastic strain on the hydrogen embrittlement of thestretch-formed tempered martensitic steel sheet were
investigated.
In this study, we used a commercial steel rod with achemical composition of 0.35C-0.18Si-0.74Mn-0.0011P-0.0017S-1.15Cr-0.15Mo (mass %). A sheet specimen of 40
× 40 × 1 mm3 was taken from the rod annealed at 850 oC for
2 h and tempered at 530 oC for 3 h and polished. Stretch
forming was conducted by using a hemispherical punchwith a radius of 8.5 mm at a crosshead speed of 1 mm min-1
until a stroke of 4.2 mm. Hydrogen was introduced by using
the cathodic hydrogen charging method in an aqueous
solution of 3% NaCl + 20 g L-1 NH4SCN. The initialpotential was -1.1 V vs/AgCl and the potential was
decreased 100 mV every 24 h. The residual stress
distribution in the sample was analyzed by finite element
method (FEM) using Abaqus cae and was measured bymeans of X-ray diffraction method at BL14B1 in SPring-8.
Figure 1 shows the crack growth behavior of the specimen.
Cracking occurred at the foot of the impression where thesample was contacted near the jig and grew along thecircumferential direction. Figure 2 shows the distributionsof the radial and circumferential stresses and plastic strain
in the stretch-formed specimen. Both measured andcalculated profiles show similar tendency, which supports
the reliability of the FEM analysis. Both the circumferential
and radial stresses at the foot were high, and thecircumferential stress became high at the edge of the region
contacted to the punch. On the other hand, plastic strain washigh around the top of the specimen. It is concluded that thepresence of tensile stress has a large effect on theoccurrence of hydrogen embrittlement of the stretch-formed
steel sheet.
[1] T. Tarui, S. Yamazaki, Tetsu-to-Hagané, 88, 612 (2002).

92

P-16

Effects of Mn addition on bainitic transformation in Fe-0.3N alloy
Mitsutaka Sato1*, Kazuki Hara2, Goro Miyamoto1 and Tadashi Furuhara1
12

Institute for Materials Research, Tohoku University
Graduate School of Engineering, Tohoku University

1. Introduction
Nitrogen (N) is an interstitial element that thermodynamically stabilizes austenite (g) in asimilar way to carbon (C). Since the eutectoid composition of the Fe-N alloy is on the higher
concentration side than that of the Fe-C alloy, more amount of N can be enriched in γ,
resulting in a larger amount of retained γ as compared to the Fe-C based alloy.
We have studied the effects of Mo, Cr and Si addition on the bainite transformation of Fe-N
alloys to develop a new high strength TRIP steel using nitrogen and it was found that thelarge amount of retained J was obtained due to the suppression of J'-FeN precipitation by Cr
addition [1]. However, since the volume fraction of retained J is still lower than that ofconventional Fe-C based TRIP steels, the effect of Mn addition on the bainite transformationof Fe-N alloys was investigated in order to obtain more retained J.
2. Experimental procedures
Fe-1mass% and -2mass% Mn alloys were used as starting materials. The samples were
nitrided at 1000 °C for 1 h. to obtain 0.3mass%N in H2/NH3 mixture atmosphere. After thenitriding, sample was dropped into a salt bath heated up to 500 °C and isothermally annealed
until 3600 s, followed by quenching into iced water. Microstructure observation was
performed by OM and SEM. The volume fraction of phases was measured by XRD andpoint-counting methods. N content at the D/J interface was measured by FE-EPMA.
3. Results
Fig.1 shows the microstructure of the samples after 3600 s holding. As shown by the white
dotted lines, the MAs between the BFs in both 1Mn and 2Mn are divided, suggesting thepossibility of decomposition of the MAs with the long time holding. In 2Mn, the width of
MAs was thicker and the volume fraction of BF was lower. XRD measurement revealed that
only diffraction peak of D was observed for 1Mn at 5 s, while α and γ peaks were observed
after 10 s. In 2Mn, only α peaks were found in 5 s and 10 s holding, and α and γ peaks were
found after 60 s. In 2Mn, only α peak was found after 5 s and 10 s holding. The diffraction
peaks of the γ' phase were not observed at any holding time.
The transformation curves for 1Mn and 2Mn are shown in Fig. 2, which were obtained frompoint counting and XRD measurements. The amount of retained γ were 14.8% for 60s holding
1Mn alloy and 16.8% for 3600s holding 2Mn, respectively, which were higher than all
samples investigated in a previous study [1]. From the comparison of the transformation
curves, the bainitic transformation is retarded by Mn addition.

Fig.1 SEM images of (a) 1Mn and (b) 2Mn transformed
at 500 oC for 3600 s

Fig.2 Transformation curves of (a)1Mn and(b)2Mn at 500 oC[1] M. Sato, S. Shimaya, G. Miyamoto, and T. Furuhara, CAMP-ISIJ 31 287 (2008).

93

P-17

Anomalous Behavior of Magnetization and Magnetic Resonancein the Chiral Helimagnet
Yuya Sawada1 and Masayuki Hagiwara2
1

Institute for Materials Research, Tohoku University
2
Graduate School of Science, Osaka University“Chirality”, which means left- or right-handedness, plays a crucial role in the symmetry
properties of nano-scale phenomena in condensed matter physics. In materials science, chiralmaterials are frequently found in molecules or crystals with helical structures, and a chiralstructure sometimes leads to the emergence of intriguing phenomena, such as chiral helicoidal
order, skyrmion lattices, and topological Hall effect.
One of the monoaxial chiral magnets CrNb3S6 is known as the material that the helicalmagnetic order with a long period is realized along the c-axis below the long-range ordering
temperature Tc = 127 K. In this material, it was theoretically predicted that the novel spin
texture, which is described as an alternate helical magnetic and ferromagnetic (FM) ordercalled the chiral soliton lattice (CSL) as shown in Fig. 1, emerges by applying a magnetic
field perpendicular to the helical axis. In 2012, Togawa et al. has succeeded the direct
observation of the CSL evolution of CrNb3S6 by using Lorenz microscopy techniques for the
first time [1].
Based on the above, we have investigated the CSL natures and dynamics in magnetic fields
by magnetization and electron spin resonance (ESR) measurements of CrNb3S6 under various
conditions. In the presentation, we will introduce the peculiar behavior of hysteresis ofmagnetization and observed novel spiked signals superposed on and ESR signal due to the
CSL dynamics [2].
This work has been collaborated with Mr. Yusuke Shimamoto, Dr. Yusuke Kousaka, Prof.
Yoshihiko Togawa (Osaka Prefecture University), Dr. Takehito Nakano (Ibaraki University),
Dr. Daichi Yoshizawa (Institute for Molecular Science), Dr. Jun-ichiro Ohe (Toho
University), Dr. Yusuke Masaki (Tohoku University), Prof. Yusuke Kato (University ofTokyo), Prof. Yasuo Nozue (Osaka University), Prof. Jun-ichiro Kishine (Open University),and Prof. Katsuya Inoue (Hiroshima University), and supported by a Grant-in-Aid for
Scientific Research (S) (No. 25220803) “Toward a New Class Magnetism by
Chemically-controlled Chirality” and JSPS Core-to-Core Program, A. Advanced Research
Networks.
[1] Y. Togawa, et al., Phys. Rev. Lett 108,107202 (2012).
[2] D. Yoshizawa, YS, et al., Phys. Rev. B 100, 104413 (2019).

Helical axis

Helicalstructure
Helical-array

FM-arrayH

Helical-array

CSL

Fig. 1. Schematic of the helical magnetic structure and the chiral soliton latticein a magnetic field applied perpendicular to the helical axis.

94

P-18

Detection of Complete Valley Polarization in Tellurium by Nonreciprocal
Magnetoresistance
K. Sudo1*, Y. Yanagi1, T. Takahashi2, K. Kobayashi2,3, M. Suzuki1 and M. Kimata1
1

Institute for Materials Research (IMR), Tohoku University2
Dept. of Phys. Okayama University
3
Research Institute for Interdisciplinary Science (RIIS), Okayama University
Elemental tellurium has a helical crystal structure and breaks mirror symmetry.
Consequently, tellurium has a spin-splitting band due to the breaking inversion symmetry andspin-orbit interaction. Another important feature in tellurium is two local maximum in band
structure in the momentum space. Therefore, tellurium has valley degrees of freedom with
opposite spin polarization [fig1 left]. This spin-valley coupling allows us to manipulate valley
polarization by applying magnetic field. When the magnetic field is applied along the c-axis(parallel to the spin-polarized axis), the energies of two valleys are lifted, and thus
valley-polarized state is achieved.
In this study, we will report the valley-polarized state by measuring nonreciprocalmagnetoresistance[1]. We observed anomalous
suppression of nonreciprocalmagnetoresistance in high magnetic fields [fig2], whereas the nonreciprocal signal is usually
proportional to magnetic field[1]. Based of our model, we have revealed that the maximum of
nonreciprocal magnetoresistance correspond to the crossover field for the complete valley
polarization.
This work is the first observation of valley polarization by nonreciprocal magnetoresistancealthough there are some observations of valley polarization by different transport probes sofar. In this study, we have also demonstrated that tellurium has much smaller magnetic field toachieve complete valley polarization compared with conventional valleytronics materials[2,3],
suggesting great advantage of this material for valleytronics.
[1] T. Ideue, K. Hamamoto, S. Koshikawa, M. Ezawa, S. Shimizu, Y. Kaneko, Y. Tokura, N.
Nagaosa and Y. Iwasa Nat. Phys. 13, 578-583, 2017[2] A. Arora, R. Schmidt, R. Schneider, M. R. Molas, I. Breslavetz, M. Potemski and R.
Bratschitsch, Nano Lett. 2016, 16, 3624-3629[3] Z. Zhu, J. Wang, H. Zuo, B. Fauque, R. D.
McDonald, Y. Fuseya and K. Behnia, Nat.
Commun. 8, 15297 2017

Figure 1 Valence band of Tellurium andvalley-polarization by magnetic field.

Figure 2 Magnetic field dependence ofnonreciprocal magnetoresistance.

95

P-19

Fabrication of 3D micro-patterned metallic glass by imprinting process
and application to Li-ion battery (LIB) electrode
Rise Takagi1, Takeshi Wada2 and Hidemi Kato2
1

Department of Materials Science, Graduate school of Engineering, Tohoku University
2
Institute for Materials Research, Tohoku University

Recently, a lot of efforts have intensively devoted to develop new electrode materials for
improving the performance of LIB. Silicon (Si) has been proposed as a promising alternative
anode active material to graphite that is used in LIB. The theoretical capacity of Si is about 10
times greater than graphite-based anode materials. However, the volume expansion of Si up to
280% upon lithiation causes self-destruction of Si active material and its delamination fromthe current collector, resulting in poor cycle properties [1].
In this study, we improve the battery performance of Si anode by using 3D microstructureson the metallic glass (MG) current collector. MG exhibits a supercooled liquid region uponheating, which allows viscous flow fabrication of nano to micro structures.
The 3D patterned MG current collector is expected to prevent the delamination of Si active
material. In addition, enlargement of specific surface due to 3D patterns, sufficient vacant
space to accommodate the volume expansion, and the excellent strength and elasticity of MG
are expected to bring a better capacity, cycle life and rate performance. Therefore, we study
fabrication 3D micro-patterns on MG by imprinting process and evaluated LIB performanceof Si anode made of the patterned MG current collector.
Pd-based MG (Pd42.5Ni7.5Cu30P20, Pd-MG) ribbons were prepared by a single-rollliquid quenching method. Imprinting process was performed and using Si molds of slit-likepatterns ( 9 µm width and 30 µm depth) fabricated by photolithography. Working electrodes
were prepared by coating slurries Si as active material (60 wt.%), CB as a conducting agent(25 wt.%), and PI (15 wt.%) as binders dissolved in NMP on a Pd-MG current collector. In
the half-cell setup, the electrode was tested in an R2032 coin-type cell, assembled with alithium foil counter electrode, a separator (PVDF) and the electrolyte (1 M LiPF6 in
EC/DMC, the use of FEC additive).
The image of imprinted Pd-MG is shown in Fig.1.. Pd-MG with a slit-like structure and22 µm in depth was successfully fabricated by imprinting tests. The fabricated Pd-MG current
collector with the active material in the structure is shown in Fig.2.. The charge-discharge
measurements revealed that the capacity of the imprinted Pd-MG based electrode was greaterthan that of the conventional copper foil based one.
[1] M. N. Obrovac, L. Christensen, D. B. Le and J. R. Dahn: J. Electrochem. Soc., 154(2007),
A849-A855.
Activematerial
Pd-MG
10 μm

10 μm

Fig. 1. SEM image of imprinted Pd-MG

Fig. 2. SEM image of Pd-MG current
collector pasted with slurry

96

P-20

Nano/Meso-scale Chemical State Visualizationof Functional Materials Using Ptychography-XAFS
Nozomu Ishiguro* and Yukio Takahashi
International Center for Synchrotron Radiation Innovation Smart (SRIS)/
Institute of Multidisciplinary Research for Advanced Materials (IMRAM),
Tohoku University, 1-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
Heterogeneity in structures and chemical states of practical function materials is often
considered one of the critical factors of their unique properties. Ptychography-XAFS, a
combination of X-ray ptychography imaging, which is the scanning-type coherent X-ray
diffractive imaging that provides real-space images of sample with 10 nm scale resolution,and XAFS spectroscopy, provides high spatial-resolution images of not only thenano/mesoscopic structures of the non-uniform materials but also their chemical states (e.g.,
composition, valence, local structures, etc.). Herein, we present applications of
ptychography-XAFS for chemical state visualization of functional materials such asheterogeneous catalysts and battery materials.
We first applied three-dimensional ptychography-XAFS to Pt-supported ceria-zirconia
automobile exhaust catalyst single particles (Pt/Ce2Zr2Ox; 7≦x≦8), which are known for
typical oxygen storage/release materials by reproductive redox between Ce2Zr2O7 (Ce3+) and
Ce2Zr2O8 (Ce4+). Three-dimensionally resolved Ce LIII-edge XAFS spectra of partially
oxidized Pt/Ce2Zr2Ox particles were successfully obtained with 40–48 nm resolution,
visualizing the heterogeneous distribution of Ce valence in the bulk of the catalyst particles.
Unsupervised data mining was then applied to visualize 3D nanoscale chemical maps, which
revealed heterogeneous reaction modes inside the individual catalyst particles during theoxygen storage processes (Fig. 1) [1, 2]. We also investigated the chemical state oflithium-titanate (LTO) particles (LixTi5O12; 4≦x≦7), which is known as an electrode-active
material for Li ion batteries. LTO particles with different charge/discharge conditions wereprepared, and spatially-resolved Ti K-edge XAFS spectra were successfully obtained (Fig. 2).
In summary, we successfully visualized chemical states of heterogeneous catalysts andbattery materials by ptychography-XAFS. This high-resolution spectro-imaging will be a
promising tool to visualize the hidden nature of materials functionalities.
[1] M. Hirose, N. Ishiguro, K. Shimomura, N. Burdet, H. Matsui, M. Tada, Y. Takahashi:
Angew. Chem. Int. Ed. 57, 1474 (2018).
[2] M. Hirose, N. Ishiguro, K. Shimomura, D.-N. Nguyen, H. Matsui, H. C. Dam, M. Tada,
Y. Takahashi: Communs. Chem. 2, 50 (2019).
(c)

×
1µm

Fig. 1. 3D Ce valence image ofpartially oxidized Pt/Ce2Zr2Ox particles.

1µm

Normalized µt /a.u.

(b)Normalized µt /a.u.

(a)
Ce valence

4950
5000
5050
Photon4960
energy4980/eV 5000

5020 5040
Photon energy /eV

Fig. 2. Absorption image and spatiallyresolved Ti K-edge XAFS of LTO particles.

97

5060

P-21

Organic-Inorganic Hybrid Nanoimprint Replica Molds
for Industrial Application
Shunya Ito*, Takahiro Nakamura, Masaru Nakagawa
Institute of Multidisciplinary Research for Advanced Materials (IMRAM),
Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577
UV nanoimprint lithography (UV-NIL) is one of industrially acceptable on-demand
micro/nano-fabrication technologies owing to its ease of use and high throughput. In UVnanoimprinting, micro/nano-structures on a mold surface are transferred onto UV cured resin
films for subsequent lithography process. Fused silica master molds, often called synthetic
quartz molds, are mainly used because of high transparence to UV light for curing, in addition
to low thermal expansion coefficient and high mechanical strength. In addition, the use of
replica molds is a way to reduce the mold cost especially in device fabrication (Fig. 1).
Organic replica resin molds are widely used; however, the resins have lower mechanicalstrength than inorganic fused silica molds. In this study, we investigated the moldperformances of hybrid materials composed of organic monomers and methacrylate-modified
inorganic silica nanoparticles (NPMC) in step-and-repeat UV nanoimprinting over 100
cycles.[1]Hybrid liquids were prepared by adding NPMC into 1,10-decanediol diacrylate (AC10) and1,10-decanediol dimethacrylate (MC10). Heterogeneous combination of polymerizablegroups, such as AC10 and NPMC, maintained a fluidity suitable for molding in UV
nanoimprinting, while homogeneous combination of MC10 and NPMC lost fluidity at asmaller NPMC content. The hybrid resin film and nanostructures comprising AC10 and NPMC
showed the increase in mechanical strength measured by nanoindentation. The hybrid moldwith 100- and 45-nm-width convex lines enabled pattern transfer without line-collapse defects
on UV cured films by step-and-repeat imprints in 128 cycles (Fig. 2). We concluded the
hybrid mold showed pattern formability through step-and-repeat imprints, which was derived
from the organic component, and durability of the mold in the imprints, which was derived
from the inorganic component.
[1] S. Ito et al., Bull. Chem. Soc. Jpn. 93, 862 (2020).
silica mold (master)$100,000

step-and-repeat UV nanoimprinting
with hybrid replica mold$0.1/shot+
AC101000 shots
resin mold (replica)$100

100- and 45-nmwidth lines

NPMC
128 cycles

1000 shots/replica moldFig. 1. Schematic illustration of the use of replica
mold reducing mold cost for industrial application.

98

Fig. 2. Step-and-repeat imprints in 128
cycles with the hybrid replica mold.

P-22

Rational design of peptide targeting intrinsically disordered protein p53
and discovery of liquid-liquid phase separation of p53
Kiyoto Kamagata1* and Tomoshi Kameda 2
1

Institute of Multidisciplinary Research for Advanced Materials, Tohoku University,
Katahira 2-1-1, Aoba-ku, Sendai, 980-8577, Japan
2
Artificial Intelligence Research Center, National Institute of Advanced Industrial Scienceand Technology (AIST), Koto, Tokyo, 135-0064, Japan
Intrinsically disordered regions (IDRs) of proteins are involved in many diseases. However,the flexible IDRs hinder the use of 3D structure-based drug design methods. Here, wedeveloped a rational design method to obtain a peptide that can bind an IDR using only
protein sequence information [1]. We applied the method to the disordered C-terminal
disordered domain of a tumor suppressor p53. The designed peptide showed the suppressionof binding to DNA and sliding along DNA by p53 using NMR, molecular dynamics
simulation, and single molecule measurements [2]. Also, we recently found that p53 itself
induces liquid-liquid phase separation through multivalent electrostatic interactions between
two IDRs [3]. We showed that the designed peptide suppressed the liquid-liquid phaseseparation of p53 by blocking the interaction of the IDRs. Sequence-based design may be
useful in targeting IDRs for therapeutic purposes.
[1] K. Kamagata, E. Mano, Y. Itoh, T. Wakamoto, R. Kitahara, S. Kanbayashi, H. Takahashi,
A. Murata and T. Kameda, Sci. Rep., 9,8584 (2019)[2] D. R. G. Subekti, A. Murata, Y. Itoh, S. Takahashi and K. Kamagata, Sci. Rep., 10, 13697(2020).
[3] K. Kamagata, S. Kanbayashi, M. Honda, Y. Itoh, H. Takahashi, T. Kameda, F. Nagatsugi,
and S. Takahashi, Sci. Rep., 10, 580 (2020)

Fig. 1. Design of peptide targeting flexible intrinsicallydisordered protein and liquid-liquid phase separation of p53

99

P-23

Analysis of the Effect of Powder Heterogeneity in Compression Molding
Yuki Kondo1*, Kizuku Kushimoto2, Shingo Ishihara2 and Junya Kano2
1

2

Graduate School of Environmental Studies, Tohoku University
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University

Powder compression molding processes are used in various products such as ceramics,
powder metallurgy and pharmaceuticals. In the processes, the microscopic structure ofcompression-molded body has an important role on the quality and productivity of the
products. For instance, the heterogeneity of the microscopic structure would influencestrength of the products. The heterogeneity is caused by differences of particle size, densityand flowability. However, the effect of powder heterogeneity on compression molding is notunderstood well because it is difficult to observe deformation behavior of small particles
directly. The purpose of this study is to investigate the effects of powder heterogeneity on
compression molding by using numerical simulations that have advantages of visualizing thedeformation behavior in detail. In this study, the effect of the yield point of elastic-plastic
materials on the deformation behavior was investigated.
Numerical simulations were used Advanced Distinct Element Method Ductile Model(ADEM Ductile Model) [1] based on Distinct Element Method (DEM) [2]. The ADEM
Ductile Model can express elastic deformation of elastic-plastic materials. In ADEM Ductile
model, joint springs are set between DEM particles to represent elastic deformation. In
addition, the plastic deformation is represented by updating the natural length of the joint
springs when the length of joint springs exceeds the Plastic starting strain (Psl).
In this study, the particles filled in a rectangular frame were compressed to investigate theeffect of the yield points on particle deformation behavior by changing the Psl. Fig. 1 shows
the pictures of simulation after compression. When Psl is small, the particles remain
deformation after unloading and fill the gaps. While, when Psl is large, the particles are not so
deformed and is similar to the original shape because the natural length of the joint spring is
not updated on the compression.
From the above, it was found that the ADEM ductile model can analyze the deformation
behavior in compression process and that the model could investigate the effects of powder
heterogeneity on compression molding.
[1] K. Ono, K. Kushimoto, S. Ishihara, J. Kano, J. Soc. Powder Technol., Japan, 56, 58-65,(2019)[2] P. A. Cundall, O. D. L. Strack, Geotechnique, 29, 47-65, (1979)(a) Psl = 0.002 [-](b) Psl = 0.02 [-](c) Psl = 0.2 [-]Fig. 1 Pictures of particles after compression when the Plastic starting length is varied

100

P-24

Stable and orthogonal DNA base pair with translocated recognition units
Hidenori Okamura1,2*, Giang Hoang Trinh1,2, Zhuoxin Dong1,2, and Fumi Nagatsugi1,2*
1

Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1
Katahira, Aoba-ku, Sendai 980-8577, Japan, 2Department of Chemistry, Graduate School of
Science, Tohoku University, 6-3 Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Japan.
All living forms on Earth utilize four distinct nucleosides - A, G, C, T - to store their
genetic information in DNA. This information is transcribed to RNA and subsequently
translated into various proteins to maintain the biological activities. Such gene expression isbased on the precise and exclusive formation of A-T and G-C canonical base pairs throughhydrogen bonding (Fig. 1a). If one can expand these genetic letters beyond the canonical
nucleobases, it would increase the functionality of gene expression system thus leading to thedevelopment of novel biotechnology and drug discovery. To this end, creation of unnaturalbase pair (UBP) is considered to be one of the most promising methods. Several researchgroups have reported sets of unnatural bases which form orthogonal pairing without
interacting with canonical ones, yet active in replication, transcription, and translation[1-3].
These UBPs have been utilized for developing nucleic acid-based nanostructures,
antibody-like structured DNA for therapeutic/diagnostic purposes as well as to expand thegenetic code for biosynthesis of artificial proteins[4]. The previously reported UBPs,
however, still have significant room for improvement with respect to achieving orthogonal
and stable base pair formation as well as the multiple/consecutive incorporation into DNA.
In order to establish a robust unnatural base pair system, in this study, we propose a new
design concept for the creation of unnatural base pairs. Our design involves the introductionof nucleobase-like hydrogen bonding units to the position isolated from the canonical bases,
thereby achieving orthogonality to the canonical nucleobases (Fig. 1b). In order to verify ourdesign concept, we chemically synthesized DNA strands containing the newly-designed
nucleosides using solid-phase DNA synthesis method and evaluated the base pairingproperties by UV melting temperature (Tm) measurement. We found that the newly designed
UBPs exhibit comparable stability to the canonical A-T and G-C pair, while the significant
destabilization was observed with the mismatched combinations. Furthermore, the CD
spectroscopic study revealed that the duplex DNA containing our UBPs adopts a global
structure similar to the fully-natural DNA. The details of molecular design, synthesis as wellas base-pairing properties will be discussed in the presentation.

Fig. 1. (a) Structures of canonical A-T and G-C base pairs and (b) the design concept of UBP proposed in this study[1] Y. Zhang, B. M. Lamb, A. W. Feldman, A. X. Zhou, T. Lavergne, L. Li, F. E.
Romesberg, Proc. Natl. Acad. Sci. USA., 114, 1317 (2017).
[2] M. Kimoto, R. Yamashige, K. Matsunaga, S. Yokoyama, I. Hirao, Nat. Biotech., 31, 453(2013).
[3] S. Hoshika, N. A. Leal, M. J. Kim, M. S. Kim, N. B. Karalkar, H. J. Kim, A. M. Bates, N.
E. Watkins Jr., H. A. SantaLucia, A. J. Meyer, S. DasGupta, J. A. Piccirilli, A. D.
Ellington, J. SantaLucia Jr., M. M. Georgiadis, S. A. Benner, Science, 363, 884 (2019).
[4] K. Hamashima, M. Kimoto, I. Hirao, Curr. Opin. Chem. Biol., 46, 108 (2018).

101

P-25

Development of a multi-turn time-of-flight electron analyzer
toward molecular orbital imaging at ultra-high resolution
Yuuki Onitsuka, Isao Nakajima and Masahiko Takahashi
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
Molecular orbital (MO) is an important concept in molecular science and especially outervalence MOs of molecule play significant roles in chemical properties such as bonding,reactivity and molecular recognition. One of tools for probing MO is electron momentum
spectroscopy (EMS) where an incident electron with an energy of the order of 1 keV or higher
is used to eject a bound electron from molecule of interest and the resultant two outgoing
electrons are detected in coincidence. The obtained EMS cross section is directly related tothe electron momentum distribution of the ionized orbital, namely EMS enables one to look at
individual MOs in momentum space. Contrary to the unique ability, EMS has been applied
mainly to small and stable molecule due to instrumental sensitivity and energy resolution. In
order to make good use of the unique ability toward various molecules involving large ones
and low-density targets, such as radicals and transient species, both improvement of thesensitivity and resolution have been required. The sensitivity has been considerably improvedby the development of a multichannel EMS apparatus [1]; however, the energy resolution has
been insufficient.
In the present study, we propose a multi-turn time-of-flight (MT-TOF) electron analyzer
with ultra-high energy resolution, which is shown in Fig. 1 [2]. The performance tests werecarried out through electron trajectory simulations which showed dramatically improvement
the energy resolution by a factor of about 27 with respect to the multichannel EMS apparatus
while maintaining the high collection efficiency. In the poster session, we will present thecurrent condition for the development and discuss our future EMS study after thedevelopment, such as its application into medicinal chemistry.
[1] M. Yamazaki, H. Satoh, M. Ueda, D. B. Jones, Y. Asano, N. Watanabe, A. Czasch, O.
Jagutzki, and M. Takahashi, Meas. Sci. Techcol. 22, 075602 (2011).
[2] I. Nakajima, Y. Onitsuka, M. Takahashi (in preparation)

Fig. 1. Schematic cross section of the MT-TOF analyzer for EMS experiments.

102

P-26

Cryo-EM structures of SERCA2b reveal the mechanism of regulation by
the luminal extension tailYuxia Zhang1, Michio Inoue1,5, Akihisa Tsutsumi2, Satoshi Watanabe1,5, Tomohiro
Nishizawa3, Kazuhiro Nagata4,5, Masahide Kikkawa2,5 and Kenji Inaba1,5*Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
2
Graduate School of Medicine, The University of Tokyo
3
Graduate School of Science, The University of Tokyo
4
Faculty of Life Sciences, Kyoto Sangyo University
5Core Research for Evolutional Science and Technology (CREST), Kawaguchi, Japan1

Sarco/endoplasmic reticulum (ER) Ca2+-ATPase 2b (SERCA2b) is a membrane protein that
conducts Ca2+ uptake from the cytosol into the ER lumen and maintains the cellular calcium
homeostasis in mammalian cells. Herein, we present cryo-EM structures of human SERCA2b
in E1•AMP-PCP and E2•BeF3- states at 2.9 and 2.8 Å resolutions, respectively (Fig. 1). The
structures revealed that the luminal extension tail (LE) characteristic of SERCA2b runs
parallel to the lipid-water boundary near the luminal ends of transmembrane (TM) helices
TM10 and TM7, and approaches the luminal loop flanked by TM7 and TM8. While the LE
served to stabilize the cytosolic- and TM-domain arrangement of SERCA2b, deletion of the
LE rendered the overall conformation resemble that of SERCA1a and SERCA2a, resulting in
multiple classes of conformations. Thus, the LE appears to play a significant role inconformational regulation in SERCA2b, which is likely involved in the different kinetic
properties of SERCA2b from those of other isoforms lacking the LE.
[1] Zhang, Y., Inoue, M., Tsutsumi, A., Watanabe, S., Nishizawa, T., Nagata, K., Kikkawa,
M. and Inaba, K.* “Cryo-EM structures of SERCA2b reveal the mechanism of regulationby the luminal extension tail”, Science Advances Vol. 6, no. 33, eabb0147. (2020)[2] Inoue, M., Sakuta, N., Watanabe, S., Zhang, Y., Yoshikaie, K., Tanaka, Y., Ushioda, R.,
Kato, Y., Takagi, J., Tsukazaki, T., Nagata, K. and Inaba, K.* “Structural basis ofsarco/endoplasmic reticulum Ca2+-ATPase 2b regulation; Cell Reports 27, 1221-1230(2019)

Fig. 1. cryo-EM structures of SERCA2b in E1•2Ca2+-ATP and E2P states

103

P-27
Suppression of alkali elution from steelmaking slag for recycling
Graduate School of Engineering, Tohoku University Zuoqiao Zhu
IMRAM, Tohoku University Xu Gao, Shigeru Ueda, Shin-ya Kitamura

Calculated values

Calcaulated values

1. Introduction:
To suppress the alkali elution, when using steelmaking slag near sea and river, we have studied thedissolution behavior of each mineral phase in steelmaking slag with and without slag modification [1].
Then, the mineralogical phases, that cause the alkali elusion, were clarified [2,4]. Based on this result,several slags were synthesized and the suppression of the alkali elusion by the control of themineralogical phases was shown [3,4]. To design the slag composition by the slag modification, in thisstudy, a model to estimate alkali dissolution was established, by combining the dissolution behaviorof each mineral phase.
2. Model construction
The dissolution rate of Ca from one crystal phase isdefined as Eq. (1), assuming the rate controlling step is a
non-steady-state diffusion through a film layer in liquid
phase. Here, A is the interfacial area between the solid
particle and leachate(m2), V is the volume of the leachate(m3); D is the diffusion coefficient in the liquid phase(m2·s-1); 𝐶𝐶𝐶𝐶𝑆𝑆𝑆𝑆𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 is the concentration of Ca at the interface
between the solid particle and leachate(mg/L), and theequilibrium value of each crystal phase is used; 𝐶𝐶𝐶𝐶0𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 is theinitial concentration of Ca (mg/L); t is time (s). After13
integration, the apparent rate constant (k’) of each crystal
pHG
phase is obtained as Eq. (2). Then, the Ca content from12F
the synthetic slag can be estimated by summarizing theEcalculated Ca content from each phase using a factor F.
11
D
The factor F is defined as Eq. (4), which expresses theCBdifference of interfacial area between that for the leaching
10
A
Synthetic slag: A,B,C,D
test of a single crystal phase and that for the leaching ofActual slag E,F,G
the same phase from slag. After calculating the9dissolution of Ca from slag, the pH of leachate is obtained
9
10
11
12
13
by Eq. (5) which has been derived from previous study [4].
Observed values
3. Leaching test of slag
Fig.1a The comparison between calculated
The above model has been applied to estimate thevalues of pH and observed ones
elution behaviors of several synthetic and industrial slags.
The elution behaviors of these slags were measured by the1000
same method as that used in the previous study [2-4].
Ca content (mg/L)
G
4. Results:
F
The calculated values of maximum pH and100
E
corresponding Ca content in leachate, for various slags
D
are shown in Fig.1a,1b with the experimental results. TheC
10B
calculated values were similar to the experimental results.
A
Synthetic slag: A,B,C,D
Therefore, this model can be considered as a useful tool
Actual slag E,F,G
to design the optimum composition of slag to suppress the1alkali elution.
1
10
100
1000
5.Conclusions:Observed values
A model has been proposed to simulate the dissolution
Fig.1b The comparison between calculated
behaviors of steelmaking slag. The simulated results
values of Ca content and observed ones
agreed well with the experimental data.
Reference[1] K. Wada et. al, Seitetsu Kenkyu, 301 (1980), 13403. [2] Z.Zhu et. al., CAMP-ISIJ, 30(2017), 755. [3] Z.Zhu et. al.,
CAMP-ISIJ, 31(2018), 683. [4] Z.Zhu et. al., ISIJ Inter, 59(2019), 1908-1916.

Zuoqiao Zhu (School of Engineering, Tohoku University, Katahira2-1-1, Sendai 980-8577)

104

P-28

Micro-damage detection using backscattering method
Micro-damage detection using backscattering method
Micro-damage detection using backscattering method

Iichiro AIZAWA，Tsuyoshi MIHARA
Iichiro AIZAWA，Tsuyoshi
Tohoku University Graduate
School of EngineeringMIHARA
Material Systems Engineering
IichiroAIZAWA，Tsuyoshi
MIHARA
Tohoku University6-6-6
Graduate
Schoolof Engineering
Material Systems Engineering
Aramaki
Aoba,
Aoba-ku, Sendai,Miyagi
Tohoku University6-6-6
Graduate
Schoolof Engineering
Material Systems Engineering
Aramaki
Aoba,
Aoba-ku, Sendai,Miyagi
6-6-6
Aramaki
Aoba,
Aoba-ku,
Sendai,Miyagi
1.Background

1.Background
While thermal power plants are required to operate with high efficiency, as for steam conditions, high1.Background
While thermal
power
plantshave
are beenrequiredto operatewith highefficiency,
as for steam
conditions,hightemperatureand highpressure
promoted.
Currently,
thermalpower generationis themainstream
inWhilethermalpower
plantsarerequiredtooperatewithhighefficiency,
as
for
steam
conditions,hightemperatureandhighpressure
have
been
promoted.
Currently,
thermalpower
generationisthemainstream
inJapan, alloy steel with high creep strength and high chromium content is used for equipment used in ultratemperatureandhighpressure
have
been
promoted.
Currently,
thermalpower
generationisthemainstream
inJapan,
alloy coal-fired
steel withplants.
high creep
strengthand high
content
is usedfor high-chromium
equipment usedsteel
in ultrasupercritical
However,it becameclearchromiumthat the creep
strengthof thealloy
Japan,
alloy
steel
with
high
creep
strengthandhighchromium
contentisusedforequipment
usedinultrasupercriticalcoal-fired
plants. However,
becameclear
that thecreepvoids
strengthof the high-chromium
steel
alloy
sharply
decreases
with long-term
use, anditthata largenumberof creepare generated
inside the thickweldedsupercriticalcoal-fired
plants.
itthatbecameclear
thatcreepvoids
strengthofareathe andhigh-chromium
steelsharply
decreaseswitha largenumberof(HAZ)
creep
are generated
insidethe thickwelded
part.
Creep
voids
occurlong-term
locallyHowever,inuse,
the andweld
heat-affected
zonethefine
grain
are several
μm
in alloysize.
sharply
decreases
withlong-term
use,
and
that
a
large
number
of
creep
voids
are
generated
insidethethickwelded
part.
Creep
voids
occur
locallyintheweld
heat-affected
zone
(HAZ)
fine
grain
area
and
are
severalμm
insize.
The power plant is regularly maintained for stable power supply and the equipment is replaced based on nonpart.
Creep
voids
occur
locallyintheweld
heat-affected
zone
(HAZ)
fine
grain
area
and
are
severalμm
insize.
The power evaluation
plant is regularly
for damaged
stable power
supplyand the equipment
is replaced cannot
based ondestructive(NDE ).maintained
However theweldsof high-chromium
steel equipment
be nonThe
power
plant
is
regularly
maintainedforstablepower
supplyandtheequipmentisreplaced
basedon
nondestructive). However
damagedwelds
high-chromium
equipment
cannotbe nondestructivelyevaluation
inspected(NDE
becausethat the thecreep
voids aretooofdeepin location steel
and aretoo smallin size,fordestructive(NDE). Howeverthedamagedwelds
ofdeephigh-chromium
steelequipment
cannotbebasednondestructivelyevaluation
inspected
becausethat the
creep
voids
are
too
in
locationand toare
small
in
size,
for
conventional
NDE
methods.
So
theseequipment
have been
replaced
only
accordingthetoooperatingtime
destructively
inspected
because
that
the
creep
voids
are
too
deep
in
location
and
are
too
small
in
size,
for
conventional
NDE
methods.
So
theseequipment
have
been
replaced
only
accordingtotheoperating
time
based
on the laboratory based material creep test without non-destructive damage monitoring. As a result, equipment
conventional
NDE
methods.
So
theseequipment
have
been
replaced
only
accordingtotheoperating
time
based
on thelaboratory
basedmaterial
creep
test without
non-destructive
damage monitoring. As a result, equipmentwithlowdamage has
beenreplaced,resultingin uneconomical
operation.
onlaboratory
basedmaterial
creep
test without
non-destructive
damage monitoring. As a result, equipment
withthelowdamage has
beenreplaced,resultingin uneconomical
operation.
2.Purposewithlow ultrasonics,
damage has which
been replaced,
resultingin uneconomical
operation.
2.PurposeUsing
is the coretechniqueof industrial inner
defects inspection method, we will develop
2.Purpose
Using
ultrasonics,
which
is
the
core
techniqueofindustrial
inner
defects
inspection method, we will develop
the creep void evaluation system at the initial stage of creep damage.
Using
ultrasonics,
which
is
the
core
techniqueofindustrial
inner
defects
inspection method, we will develop
theExperimental
creep void evaluation
systemat the initial stage of creep damage.
3.
results anddiscussion
the
creep
void
evaluation
systemattheinitial
stage
of
creep
damage.
3. Although
Experimental
and discussion
it hasresults
been thoughtthat it is impossible to detect creep
3. Experimental
results
and discussion
Althoughit hasµm
beenthought
is impossible
to (30detectcreep
voidsof several
generatedinthatthe itdeep
part of steelmm)byAlthough
it
has
been
thoughtthat
itis
impossible
todetect
creep
TypeB
voids
of
severalµm
generated
in
the
deep
part
of
steel
(30
mm)
by TypeA
ultrasonic measurement, the authors tried a method to evaluate usingvoidsofseveralµm
generated
in
the
deep
part
of
steel
(30
mm)
by
TypeB
ultrasonicmeasurement,
the authors
a method toevaluateusing TypeAtheultrasonicbackscattering
method.tried
Backscatteredwaves
generated
TypeB
ultrasonicmeasurement,
the authorstried
a methodtoevaluateusing
themicrostructures
ultrasonicbackscattering
method.
Backscatteredwaves
generatedbyare largerforhigh-frequency
ultrasonicwaves,and TypeAtheultrasonicbackscattering
method.
Backscatteredwaves
generatedbyismicrostructureslarger for
high-frequency
ultrasonicanditthought thatthearedetection
sensitivityof creepvoids
is waves,
higher.
Onbymicrostructuresarelargerforhigh-frequency
ultrasonicwaves,
andFig.1 Aspherical angle focusing acoustic
itisthoughtthatthedetection
sensitivity
of
creep
voids
is
higher.
On
the other hand, high-frequency ultrasonic waves also have large
lens designangle focusing acoustic
Fig.1 Asphericalitisthoughtthatthedetection
sensitivity
of
creep
voids
is
higher.
On
the other hand,
high-frequency
also have large
attenuation
duringpropagation, ultrasonicwhich iswaves
disadvantageousfor
Fig.1 Asphericalangle focusing acoustic
lens design
the
other
hand,
high-frequency
ultrasonic
waves
also
have
large
attenuationtransmitted
during propagation,
which waves
is disadvantageousfor it is essential
receivingwaves and scattered
to deep steel, andto ensure the sensitivity oflens
designattenuation
duringpropagation,
which onwaves
is simulations
disadvantageousfor it is essential
receiving transmitted
waves
and scattered
to deep andsteel,
andto ensuresensitivity oftransmitted
andreceived
signals.
Basedpreliminary
experimentson thethepropagation
receivingtransmitted
waves
and
scattered
waves
to
deep
steel,
anditisessential
toensurethesensitivityoftransmitted
andreceived
signals.
Basedonsimulations
andpreliminary
experimentsonthepropagationofultrasonic waves and the evaluability of creep voids, we examined the difference in creep void density
detectiontransmitted
andreceived
signals.
Basedonsimulations
andpreliminary
experimentsonthepropagationofultrasonicandsteelthe evaluabilityof creep voids,
we examinedthe difference
creepaperture)void density
inthe deepwaves
part ofdue to the difference
in ultrasonicfocusing(large and insmall
usingdetection
a waterultrasonic
waves
and
the
evaluabilityofcreep
voids,
weexaminedthedifference
in
creep
void
densitydetectionin the deepimaging
part of steel
duewhichto theis difference
in ultrasonicfocusing(large anddevice.
small Theaperture)using imaging
a waterimmersion
device,a laboratory-based
rigorousmeasurement
submergedinthe deeppart of steel
totheis difference
ultrasonicfocusing(largepitch
anddevice.
aperture)using
a waterimmersion
imagingdevice,which
a lenslaboratory-based
rigorousThe
imagingdevicemechanicallyscansduetheacoustic
in theinXY
directions
at measurementa minute
tosmallcreateansubmerged
acoustic
image
that
immersion
imagingdevice,whichisalaboratory-based
rigorousmeasurement
device.
The
submerged
imagingdevicemechanically
scans
the
acoustic
lens
in
the
XY
directionsataminutepitchtocreateanacoustic
image
that
reflects the amplitude of the received signal at an arbitrary depth. The test piece cut out from the actual thermal
2devicemechanically
scans
the
acoustic
lens
in
the
XY
directionsataminutepitchtocreateanacoustic
image
reflectsplant
the amplitudeof the ofreceived
signal900/mm
at an arbitrary
Theoftestfrom thefrequency
actual thermal
power
has a maximum
creep voidsin the depth.
deep part
thepiecesteel.cut
Theoutultrasonicisthat102
reflects
theamplitudeofthereceived
signalat
anarbitrarydepth.
The
test
piece
cut
out
from
the
actualthermalpower theplant
a maximumof creepvoids
900/mmin isthe1 deepof thesteel.
ultrasonicfrequency
10
MHz,
XYhas
scan
is 1 µm pitch,and thescanningrange
mm ×part
1 mm.
Since
theThecreep
void is expected
to is
have
2
power
plant
a maximumof creep
voids
in is
the1 deepof thesteel.
The
ultrasonicfrequency
is
10
XYhas
scan
is 1 µm
and wavethescanning
range
mmit×partmm.
Since
theextracting
creep
void
expected
haveaMHz,
largerthe
amplitude
than
the pitch,scatteredof900/mm
the fine
structure,
is1 evaluatedbytheisnumber
oftobright
the
XY
scan
is
1
µm
pitch,
andthescanning
range
is
1
mm
×
1
mm.
Since
the
creep
void
is
expected
to
have
aMHz,
largeramplitude
thanthescattered
wave
of
the
fine
structure,itisevaluatedbyextracting
thenumberofbrightpoints above a certain threshold in the acoustic image. As a result, it was suggested that it is possible to detect theadegreelargerabove
thevoids
scattered
wave
ofthe
the
fine structure,
it moreisit evaluatedextracting
thenumberof bright
pointsa certain
thresholdin
acoustic
image.
As awavesresult,wasusingsuggestedthat it is possible
tolens.
detecttheofamplitudedensityofthancreep
bythe
focusing
ultrasonica bylarge-aperture
acoustic
Next,
pointsabove
acertainthresholdintheacoustic
image.
Asaresult,itwassuggested
that
it
is
possibletodetectthedegree of densityof creep voidswe
bydesigned
focusingand
the developed
ultrasonic waves
more usinga large-aperture
acoustic
lens.
assuming
actual measurement,
an asphericaloblique-angle
focusing
acoustic
lensNext,
thatdegreeultrasonicof densityof creepvoids
bydesigned
focusing
theefficiently
ultrasonicfocuses
waves
more
using
large-aperture
Next,
assuming
actual waves
measurement,
weanddeveloped
an asphericaloblique-angle
that
emits
at an
obliqueangle andata depthofa30
mm infocusingorderacoustic
toacoustic
avoid lens.
thelens
effects
assuming
actualmeasurement,
wedesignedanddeveloped
anasphericaloblique-angle
focusing
acoustic
lens
emits
ultrasonic
waves
at
an
obliqueangle
andefficiently
focuses
at
a
depth
of
30
mm
in
order
to
avoid
the
effectsof HAZ (Fig. 1). Two types of acoustic lenses were designed and fabiricated. Fig.2 and 3 show the comparisonthatofemits
ultrasonicwaves
at an ofobliqueangle
efficiently
ata depth
ofFig.2
30specimen
mm
tothe
avoid
the
effectsof HAZ(Fig.
1).dueTwototypes
acoustic
lensesweredesignedand fabiricated.
andin3ordershow
comparisonofacoustic
images
creep
void
using
twoandacoustic
lens.focuses
In bothlens,damaged(rightimage)
observed
of
HAZ
(Fig.
1).dueTwoofvoidacoustic
lenseswere designed
and fabiricated.
Fig.2
and
3 show
thecomparisonofacoustic
imagestotypes
creep
usingvoids.
two acoustic
lens.toInFig.2
bothlens,3,damaged
specimen(rightimage)
observedmanybrightspots
due
to dense
creep
Comparingandthe thinnerwedgesof type
B weremore
acoustic
imagesdue
to creep
void
using
two
acoustic
lens.
both andlens,3,
damagedspecimen(rightimage)
observedmanybrightspots
due
to From
dense
creep
voids.
Comparing
toInFig.2
thethinnerwedgesof type
B be
were
more
sensitive
for creep
voids.
theabove
results,
it wassuggestedthat
thedensityof creep
voids
could
detectedmanybright
spots
due
to
dense
creep
voids.
Comparing
to
Fig.2
and
3,
the
thinnerwedges
of
type
B
were
more
sensitiveforcreep
voids.
From
the
above
results,itwassuggestedthat
thedensity
of
creep
voids
could
be
detectedby evaluating the acoustic image based on the scattered wave amplitude produced by scanning a high-focus
sensitiveforcreep
voids.
From
the
above
results,itwassuggestedthat
thedensity
of
creep
voids
could
be
detectedby evaluating
acoustic imagepitch.
basedInon
scattered wave amplitude produced by scanning a high-focus
acoustic
lens atthe
a high-definition
thethefuture,material Area
Voids Area
Area
Voids Areabyevaluating
acoustic
basedInonthescatteredBasewave
amplitude
produced Basebymaterial
scanning
a high-focus
acousticatthe
a high-definition
pitch.
thefuture,wewilllensproceedwith image
verification
includingBase material Area
Voids Area
Base material Area
Voids Area
acoustic
ata high-definition
pitch.
thefuture,wewilllensproceedwithverification
includingmeasurement
frequency,
scanning
pitch,Inandacoustic
Base material Area
Voids Area
Base material Area
Voids Area
we
will
proceedwithverification
includingmeasurement
frequency,
scanning
pitch,
andacoustic
image processing method, and develop a system thatmeasurement
scanning
pitch,
andacoustic
image
method,and develop
systemthatcanbe processing
used forfrequency,
equipment
inspectionof aactual
plant.
image
processing
method,anddevelopasystemthatcan be used for equipment inspection of actual plant.
Fig.2 Acoustic image (type A) Fig.3 Acoustic image (type B)
can be used for equipment inspection of actual plant.
Fig.2 Acoustic image (type A) Fig.3 Acoustic image (type B)

105Fig.2 Acoustic image (type A) Fig.3 Acoustic image (type B)

P-29

Hydrogen Oxidation Reaction and Hydrogen Peroxide Generation
Properties of Vacuum-Prepared Ru/Ir(111)
K. Hayashi*, K. Kusunoki, R. Sato, D. Kudo, N. Todoroki and T. Wadayama
Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579

Tip Current, iT / nA

Intensity / a.u.

Prolonged lifetime is necessary for the wide-spread commercialization of polymer
electrolyte membrane fuel cell (PEMFC), and thus, to prevent deterioration of the components
under PEMFC operating conditions is crucial. From this viewpoint, development of thecatalyst materials is of great importance because Pt nanoparticles supported on carbon black(Pt/C), which is generally used for both the cathode and anode catalysts, cause several typesof degradation. For example, the Pt/C anode catalyst promotes not only hydrogen oxidation
reaction (HOR); the anode reaction of PEMFC, but also H2O2 generation via a two-electron
reduction of O2 which comes from air. The generated H2O2 forms radical species of O* that
deteriorate the PEM, leading to the degradation of PEMFC performance [1]. Thus, catalystmaterials of less-active H2O2 generation with sufficient HOR activity are required for theanode catalyst. Recently, Ir-Ru catalysts are reported to show the Pt/C comparable HOR
activity [2]. However, relation between the surface atomic compositions of the Ir-Ru and boththe H2O2 generation and HOR properties are not clarified yet. We investigated in this work,
the HOR and H2O2 generation properties of the well-defined Ru/Ir(111) bimetallic surfaces
fabricated in ultra-high vacuum (UHV；f10-8Pa).
673K-Ru/Ir(111)773K-Ru/Ir(111)
Ru/Ir(111) bimetallic surfaces were prepared as Ir-Ru
Ru:Ir873K-Ru/Ir(111)(mol/mol)Irmodel catalysts by an arc-plasma deposition of 1
Ru
44:56
monolayer-thick Ru at a substrate temperature of T (T =673, 773, 873 K) on UHV-surface-cleaned Ir(111)
33:67
substrate. The topmost surface atomic compositions were
estimated by low-energy ion scattering spectroscopy
21:79(LE-ISS) in UHV. The HOR and H2O2 generation
0.80
0.85
0.90
0.95
1.00
properties were evaluated in respective solutions by using
E / E0scanning electrochemical microscope (SECM).
Fig. 1. LE-ISS spectra for
LE-ISS spectra for the Ru/Ir(111) surfaces are shown in
the Ru/Ir(111).
Fig. 1. Judging from the estimated top-surface atomic
10.0
compositions, the surface Ru decreased with increasing the673K-Ru/Ir(111)773K-Ru/Ir(111)
8.0
substrate temperatures through thermal diffusions of the873K-Ru/Ir(111)
Ru atoms into the substrate Ir. Fig. 2 presents the H2O2
Ir(111)
6.0
Pt(111)
generation properties evaluated in O2-saturated 0.1 M
4.0
HClO4 by using SECM. In this method, the Pt micro tip
2.0
electrode (φ ~ 20 μm) was hold about 40 µm above thesample surface at constant potential, and then the tip
0.0
0.0
0.2
0.4
0.6
0.8
1.0
1.2
current, which corresponds to the detection of the H2O2
Substrate Potential, ES / V (vs. SHE)
generated at the sample surfaces, was collected with
Fig. 2. H2O2 detection tip
sweeping sample potentials from 0.05 to 1.2 V vs. SHE.
current
vs. applied potentials.
Throughout the measured potentials, all the Ru/Ir(111) andIr(111) generated less amounts of H2O2 than Pt(111). Especially, 773 K-Ru/Ir(111) exhibitedthe lowest H2O2 generation property (@0.1V vs. SHE) among the tested samples. Thus, thetopmost surface composition of Ir:Ru ~ 1:2 could be the most appropriate to suppress H2O2
generation for the Ir-Ru catalyst. The HOR activities of the samples will be also discussed.
[1] R. Borup et al., Chem. Rev. 107, 3904 (2007).
[2] E. You, M. Min, S. Jin, T. Kim, and C. Pak, J. Electrochem. Soc. 165, F3094 (2018).

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Visible-light-induced antibacterial activity of TiO2 layer formed by thetwo-step thermal oxidation of Ti
Ryusuke Koizumi1, Kyosuke Ueda1, Koyu Ito2, Kouetsu Ogasawara2, Takayuki Narushima1,3
1

Department of Materials Processing, Tohoku University,
Department of Immunobiology, Institute of Development, Aging and Cancer (IDAC),
Tohoku University,
3
Research Center for Structural Materials, National Institute for Materials Science (NIMS)
2

Titanium and its alloys are widely used in biomaterials owing to their excellent corrosion
resistance, bone compatibility, and mechanical properties. The benefits of Ti are widely
recognized in dentistry; however, Ti dental implants possess the risk of infections caused by
the adhesion of bacteria [1]. Therefore, surface treatments that impart antibacterial properties
to Ti are necessary. The antibacterial activity of TiO2, which is due to its photocatalytic
activity, can be effectively utilized for biomedical applications [2]. Additionally, TiO2
exhibits photocatalytic activity when exposed to ultraviolet (UV) light; however, UV
radiation can potentially harm human body. Consequently, visible-light-induced antibacterial
properties are essential. In our previous study, the carbon-added and anatase-rich TiO2 layer
formed through the two-step thermal oxidation of Ti showed antibacterial activity after
visible-light irradiation for 14.4 ks [3]. The addition of nitrogen to the TiO2 layer was
expected to contribute the most to visible-light responsiveness. In this study, nitrogen-added
TiO2 layers were generated through the two-step thermal oxidation of Ti in a N2-richatmosphere and the antibacterial ability of these layers under visible-light irradiation was
evaluated.
Commercially pure Ti (Gr. 2) plates with a diameter of 12 mm (single-side
mirror-polished) were used as the substrate materials. First, the substrates were subjected tocarbonitrization (N2-1% CO, 1073 K, 3.6 ks). Subsequently, the materials were oxidized(N2-1% O2, 773–973 K, 10.8 ks and 973 K, 3.6–21.6 ks). The phases of the surface reaction
layers were identified using X-ray diffraction, and the cross-section was observed using ascanning electron microscope. The chemical compositions of the reaction layers wereanalyzed through X-ray photoelectron spectroscopy. After oxidation, the antibacterial activityof the specimens under visible-light irradiation was evaluated by a glass adhesion method ofEscherichia coli (E. coli), with JIS R 1752: 2013 as the reference.
During oxidation, an anatase-rich TiO2 layer, a rutile-rich layer, and a rutile single-phaselayer were produced at 773, 873, and 973 K, respectively. It was confirmed that nitrogen was
dissolved in the TiO2 layers. Furthermore, the TiO2 layers irradiated with visible light had asignificantly lower normalized number of viable bacteria (E. coli) than that of the TiO2 layers
kept in the dark. In particular, the rutile single-phase TiO2 layer fabricated at 973 K for
7.2–10.8 ks showed the highest reduction after visible-light irradiation and had anantibacterial activity value of ~3.
[1] P.A. Norowski and J.D. Bumgardner, J. Biomed. Mater. Res. 88B, 530–543 (2009).
[2] K. Sunada, T. Watanabe and K. Hashimoto, J. Photochem. Photobiol. A156, 227–233(2003).
[3] T. Ueda, N. Sato, R. Koizumi, K. Ueda, K. Ito, K. Ogasawara, and T. Narushima, Dent.
Mater, in press. (2020).

107

P-31

MnTe-based phase change memory with displacive polymorphic
transformation
Shunsuke Mori1*, Daisuke Ando1 and Yuji Sutou1
1

Dept. of Materials Science of Engineering, Tohoku Univ., Sendai, Japan

The phase change material (PCM) is known to show phase transition between amorphousand crystalline phases with large contrasts in optical and electrical properties [1]. Ge2Sb2Te5(GST225) is well known as a typical PCM. In optical disk or semiconductor memories, PCMs
are used for a memory layer. Recently, new PCMs showing a transition between different two
crystalline phases have much attention because of its melting-free process without
amorphization, enabling very lower energy- and fast operation- memory. For example,
GeTe/Sb2Te3 superlattice (GeTeSL) and single crystal In2Se3 are known to be melting-free
PCMs showing very low energy operation [2,3].
MnTe is known as a polymorphic compound. According to Mn-Te binary phase diagram, β(wurtzite-type structure) and α (NiAs-type structure) phases are known to be stable phase inhigher temperature region (more than 900 ℃) and at room temperature, respectively [4].
Recently we found that the sputtered MnTe films show the transformation from the β to stable
α phase [5,6]. Moreover, the optical and electrical properties of the MnTe films changed uponthe β→α polymorphic transformation drastically. In this study, we investigated the memory
characteristics of the MnTe polymorphic film.
Mn-Te films on Si (725 μm) / SiO2 (100 nm) substrates were prepared by radiofrequency
magnetron sputtering at room temperature. MnTe-based memory device was fabricated using
conventional photolithography and focus ion beam (FIB) technique. The memory device wasannealed to obtain α-MnTe before the measurement. The memory characteristics of obtained
devices were evaluated by a semiconductor parameter analyzer. In order to investigate theoperation mechanism in memory devices, a cross-sectional image of a phase change region wasobserved using transmission electron microscopy (TEM). TEM samples were fabricated using
FIB technique.
The MnTe-based memory devises showed a reversible resistive switching with increasing
applied pulse voltage. Such a resistive switching behavior was observed even under the pulse
width of 10 ns, indicating that the MnTe can show very fast transition speed. According to thecalculation of the operation energy, the MnTe was found to achieve more than 90 % reductionof energy consumption in the conventional memory using GST225. Our TEM observation also
revealed that the phase change region is a β' phase which has a wurtzite-type structure but thecoordinates of the Te atoms are slightly different from the β phase. The atomic-column image
at α/β' phase boundary revealed that the α/β' polymorphic change can be achieved by adisplacive transformation without a long-range atomic diffusion. The atomic-displacement in
MnTe polymorph enable the very fast and low energy memory operation [7].
[1] M. Wuttig, and N. Yamada, Nat. Mater. 6, 824 (2007).
[2] R. E. Simpson, P. Fons, A. V. Kolobov, T. Fukaya, M. Krbal, T. Yagi, and J. Tominaga,Nat. Nanotechnol. 6, 501 (2011).
[3] M. S. Choi, B. Cheong, C. H. Ra, S. Lee, J. Bae, S. Lee, G. Lee, C. Yang, J. Hone, and W.
J. Yoo, Adv. Mater. 29, 1703568 (2017).
[4] M.E. Schlesinger, J. Phase Equil. 19, 591 (1998).
[5] S. Mori, Y. Sutou, D. Ando, and J. Koike, Mater. Trans. 59, 1512 (2018).
[6] S. Mori, D. Ando, and Y. Sutou, Mater. Des. 196, 109141 (2020).
[7] S. Mori, S. Hatayama, Y. Shuang, D. Ando, and Y. Sutou, Nat. Commun. 11, 85 (2020).

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P-32

Flow Stress Modeling of Alloy 720Li Using Internal State Variables ModelJo Nakamura1*, Nobufumi Ueshima1 and Katsunari Oikawa1
1

Department of Metallurgy, Graduate School of Engineering, Tohoku University
6-6-02 Aza-Aoba Aramaki, Aoba-ku, Sendai 980-8579, Japan

Alloy 720Li is a kind of precipitation strengthening Ni-based superalloy and is known as aforging material for turbine discs in aircraft engines. Hot forging not only improves
workability by dynamic softening associated with microstructural changes such as dynamic
recrystallization (DRX), but also brings out the mechanical properties by controlling thepost-work structure [1]. Since flow stress and microstructure are closely related to each other,
it is necessary to construct a flow stress model that takes these relationships into account inorder to develop a manufacturing process that improves Workability and mechanicalproperties. The purpose of this study is to establish a flow stress model of Alloy 720Li byconsidering the effect of work hardening, dynamic recovery, DRX and grain-boundary
strengthening by using internal state variables (ISV) model [2] based on the dislocation
theory.
As-received Alloy 720Li cylindrical test specimens with a diameter of 8 mm and a heightof 12 mm were homogenized at 1104 ℃ for 4 h and air cooled. Hot compression tests werecarried out at temperatures of 1050 ℃, 1100 ℃ and 1150 ℃, strain rates of 0.001 s-1, 0.01 s-1
and 0.1 s-1 and true strain of 0.5 and 0.7. Flow stress was modeled by optimizing parameters
so that the sum of the squares of the differences between the flow stress values obtained fromthe hot compression tests and the calculated values by ISV model were minimized. The
specimens were cut in the compression direction and their microstructure was observed byscanning electron microscope (SEM).
Fig. 1 shows the flow stress curves obtained by the compression tests and calculated by
ISV model. The error between the experimental and calculated values was 6.6 % at 1100 ℃
and 1150 ℃ except for 0.001 s-1, which shows flow behavior was well described by ISVmodel. However, at 1050 ℃, the constitutive equation used in this study did not work well.
The results of microstructure observation are shown in Fig. 2. Tertiary γ’ phase was observed
before the compression test and in the compressed specimens at 1050 ℃ but was not observedin the compressed specimens at 1100 ℃ and 1150 ℃. These results suggest that the effect ofprecipitation on the constitutive equation is a possible reason for the deviation.
[1] F. Liu, J. Chen, J. Dong, M. Zhang and Z. Yao, Mater. Sci. Eng. A 561, 102(2016).
[2] J. Lin, Y. Liu, D. C. J. Farrugia and M. Zhou. Philos. Mag. 85 1967(2005).

Fig. 2. BSE images for each condition.
Strain 0.5, Strain rate 0.01 s-1

Fig. 1. Comparison of experimental andcalculated flow stress curve

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P-33

Thin-Film Properties of BTBT Derivatives with
Oligo(ethylene oxide) Chains
Taichi Imai1,2, Kohsuke Kawabata1,2 and Kazuo Takimiya1,2
12Graduate School of Science, Tohoku University
Center for Emergent Matter Science (CEMS), RIKEN

One of the important advantages of organic semiconductor materials is solutionprocessability, which enables low-cost fabrication of electronic devices. However, the materials
with good charge transport properties such as 2,7-diphenyl[1]benzothieno[3,2-b][1]benzothiophene (DPh-BTBT)[1] and dinaphtho[2,3-b:2′,3′-f]-thieno[3,2-b]thiophene (DNTT)[2]are difficult to apply to solution-processing due to their low solubilities. To improve thesolubility, bulky alkyl substituents were introduced frequently[3]. However, such bulky
substituents may change the crystal structures favorable for charge transport. Therefore, thesearch for soluble substituents with little steric hindrance is important for the development ofsoluble organic semiconductor materials with good charge transport properties.
In this study, we synthesized DPh-BTBT derivatives 1, 2, and 3 with oligo(ethylene oxide)
and/or alkoxy groups (Fig. 1). Oligo(ethylene oxide) chains are known as soluble substituentswith a linear structure[4]. 1 has low solubility in chloroform comparable to that of DPh-BTBT,
while 2 and 3 have high solubilities enough for solution-processing. X-ray diffraction patternsof thin films of 2 and 3 fabricated by spin-coating indicated that the films have layer structuresin the out-of-plane direction and the film of 2 has the herringbone arrangement in the in-plane
direction (Fig. 2). Furthermore, organic field-effect transistors (OFETs) with 2 and 3 as active
layers showed p-type charge transport properties, and the device based on 2 showed the holemobility of up to 0.83 cm2/Vs under vacuum (Fig. 3).

Vd = −50 V−Id / A

1E-3
1E-4
1E-5
1E-6
1E-7
1E-8
1E-9
1E-10

Fig. 1. Stuructures of DPh-BTBT derivatives

1000000(001)

intensity (arb.unit)

100000

(110)
(003)

10000
1000
100

(005)

(020)

(120)

In-planeOut-of-plane
0

5

10

15

20

25

30

2θ (degree)

Fig. 2. XRD patterns of the film of 2

110

-50

-30
-10
Vg / V

10

0.014
0.012
0.010
0.008
0.006
0.004
0.002
0.000

Fig. 3. Transfer curve of 2(-Id)1/2 / A1/2

[1] K. Takimiya et al., J. Am. Chem. Soc. 2006, 128, 12604−12605.
[2] T. Yamamoto et al., J. Am. Chem. Soc. 2007, 129, 2224−2225.
[3] M. Sawamoto et al., ACS. Appl. Mater. Interfaces 2016, 8, 3810−3824.
[4] J. Mei et al., Chem. Mater. 2011, 23, 2285−2288.

P-34

Exosome-targeting probe containing an environment-sensitive
fluorophore introduced into amphipathic helix peptide
Kazuki Kuwahara1, Kenta Mogami1, Yusuke Sato1,2 and Seiichi Nishizawa1
1

Department of Chemistry, Graduate School of Science, Tohoku University, Sendai,Japan
2JST, PRESTO, Tokyo, Japan
Exosome, a kind of extracellular vesicles with about 30-150 nm in diameter, contains
various nucleic acids and proteins inside, and it has been revealed that they are greatly
involved in various diseases and cancers through intercellular communication. Hence, its
functional analysis is indispensable for pharmaceutical applications [1]. Whileimmunoassays like ELISA have been widely used for its quantification, some of themcannot be detected in principle [2]. Here, we report on the new class of exosome-binding
fluorescent probe based on amphipathic helical peptide as a universal analytical tool formarker-free manner. This probe can be inserted hydrophobically into the lipid packing
defects (LPDs) that can be commonly found in exosome-sized vesicles [3], which
provides the detection of various kinds of exosomes without the bias from the surface
protein diversity.
We selected C-terminal amphipathic region of human apolipoprotein A-I (ApoC) as
the exosome recognition unit and Nile red (NR) was attached to N-terminal of ApoC. The
resulting probe (ApoC-NR) was found to show the fluorescence enhancement response
and the increase signal of CD at 208 and 222 nm, indicators of a-helicity, upon binding
to K562 exosome. These results suggest that the ApoC unit binds to the LPDs on the
exosome surface, and the NR unit is distributed inside the membrane. Though thefluorescence response was dependent on the exosome concentration and the detection
limit was comparable to ELISA (Fig. 1), the detection sensitivity was not affected bydifferent release cells (BPH-1, A549 and U87MG). Moreover, our method has a great
advantage as an analysis tool that is extremely quick and simple (~5 min) over ELISA.
Consequently, we found that ApoC-NR, the exosome-binding fluorescent probe based on
our unique probe design, is useful as a new analytical tool that overcomes the problemsof ELISA [4]. We envision that our approach will be powerful and helpful for practical
medical applications.
[1] S. Mathivanan, H. Ji, and R, J. Simpson, J. Proteomics, 2010, 73, 1907-1920.
[2] M. Jorgensen, R. Baek, S. Pedersen, E. K. L. Sondergarrd, S. R. Kristensen and K. K.
Varming, J. Extracell. Vesicles, 2013, 2, 20920[3] S. Vanni, H. Hirose, H. Barelli, B. Antonny and R. Gautier, Nat. Commun., 2014, 5,
4916.
[4] Y. Sato, K. Kuwahara, K. Mogami, K. Tahakashi, and S. Nishizawa, RSC Advances,
2020, DOI: 10.1039/d0ra07763a.

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Electronic excitations in high-Tc superconducting cupratesby oxygen K-edge resonant inelastic X-ray scattering
Yukihiro Matsubayashi and Sumio Ishihara
Department of Physics, Tohoku University
In the resonant inelastic X-ray scattering (RIXS) processes, core electrons are resonantly
excited by an incident X-ray, and then the X-ray is scattered when electrons are relaxed. It is
widely recognized that the RIXS enables us to obtain information on the momentum- andenergy-resolved elementary excitations of correlated materials, which are not accessible byother methods. Theoretical calculations play a large role for the interpretation for RIXS
spectra, which are described by the second-order perturbation theory with respect to theelectron-photon interaction. La2CuO4, the parent material of high-Tc superconducting
cuprates, is a charge-transfer insulator and offers a starting point for understanding the origin
and anomalous electronic states of the high-Tc superconductors. An experimental study ofoxygen K-edge RIXS found that the Zhang-Rice singlet (ZRS) is formed by an electronic
excitation from the oxygen to the copper atoms [1]. In order to reproduce the observed
oxygen K-edge RIXS spectra, we need to take the oxygen orbitals into account. However,theoretical analyses of the detailed momentum dependence of the oxygen K-edge RIXS
spectra have not been reported so far.
In this study, we analyzed the oxygen K-edge RIXS spectra on the basis of the Keldysh
formalism [2]. We obtained the RIXS spectra shown in Fig. 1 by using the cluster
perturbation theory (CPT), which reproduces the recent experimental results. There are the
ZRS excitations from 1.5 to 3 eV and the charge-transfer excitations around 4 eV. These
spectra are consistent with the results of a 2 by 2 cluster obtained by the exact diagonalization
method as shown in Fig. 2.
[1] K. Okada and A. Kotani, Phys. Rev. B65, 144530 (2002).
[2] J. Igarashi and T. Nagao, Phys. Rev. B88, 014407 (2013).

Fig. 1. Oxygen K-edge RIXS spectra calculated by the
CPT method.

112

Fig. 2 Oxygen K-edge RIXS spectra calculatedby the ED method.

P-36

High-Resolution ARPES Study on the Origin of High-Temperature
Superconductivity in FeSe1−xTex/CaF2
K. Nakayama1,2*, R. Tsubono,1 G. N. Phan,1 F. Nabeshima,3 N. Shikama,3 T. Ishikawa,3
Y. Sakishita,3 S. Ideta,4,5 K. Tanaka,4,5 A. Maeda,3 T. Takahashi,1,6,7 and T. Sato1,6,7
1

Department of Physics, Tohoku University
Precursory Research for Embryonic Science and Technology (PRESTO),
Japan Science and Technology Agency (JST)3
Department of Basic Science, the University of Tokyo
4
UVSOR Synchrotron Facility, Institute for Molecular Science5
School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI)
6
Center for Spintronics Research Network, Tohoku University
7
WPI Research Center, Advanced Institute for Materials Research, Tohoku University
2

One of outstanding physical properties of iron-based superconductors is electronic
nematicity characterized by spontaneous breaking of the rotational symmetry in the electronic
structure. Since nematicity appears in the proximity of the high-temperature superconducting
phase, the interplay between nematicity and superconductivity is a central issue in the current
research of iron-based superconductors. Iron-chalcogenide superconductor FeSe1-xTex is an
ideal system to investigate this issue, because (i) the parent FeSe (x = 0) shows uniquenematicity without antiferromagnetic order [1] that complicates the electronic states and (ii)Te substitution leads to the highest Tc among non-carrier-doped FeSe system at ambientpressure [2]. However, the evolution of nematicity with Te substitution and the mechanism ofhigh-temperature superconductivity have remained unresolved. In this study, by utilizing
angle-resolved photoemission spectroscopy (ARPES), we have succeeded in determining theevolution of the electronic structure as well as nematicity in FeSe1-xTex across the critical Te
concentration (xc), above which the high-temperature superconductivity emerges. Our
comprehensive study provides an important insight into the interplay between
high-temperature superconductivity and nematicity in iron-chalcogenide superconductors.
[1] K. Nakayama, Y. Miyata, G. N. Phan, T. Sato, Y. Tanabe, T. Urata, K. Tanigaki, and T.
Takahashi, Phys. Rev. Lett. 113, 237001 (2014).
[2] Y. Imai, Y. Sawada, F. Nabeshima, and A. Maeda, Proc. Natl. Acad. Sci. USA 112, 1937(2015).

Fig. 1. (a) Phase diagram of FeSe1-xTex/CaF2. (b) Representative APRES-intensity
plot and (b) corresponding second-derivative-intensity plot measured at T = 30 K for
FeSe/CaF2 (x = 0).

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Electrical resistivity measurements under high pressurefor iron-based ladder material BaFe2(S1-xSex)3
R. Nojima, T. Aoyama, Y. Imai, and K. Ohgushi
Department of physics, Graduate School of Science, Tohoku University
The iron-based materials BaFe2X3 (X = S and Se), which exhibit pressure-induced
superconducting transitions, are Mott insulators due to the strong electron correlation
effect inherent in a quasi-one-dimensional ladder lattice at an ambient pressure [1, 2]. As
in the case of iron-based superconductors with a two-dimensional square lattice, theorbital ordering derived from the multi-orbital nature of Fe2+ ions is observed in BaFe2X3;
a slight anomaly in the electrical resistivity owing to the orbital ordering appears above
the antiferromagnetic transition temperature. The antiferromagnetic/orbital orderingtransition temperatures are 115 K/200 K for BaFe2S3 and 255 K/400 K for BaFe2Se3. The
possible orbital-ordering pattern is a ferroic order of dx2 – y2 orbitals in BaFe2S3, and astaggered order of dx2 – y2 and dxz orbitals in BaFe2Se3. In a solid solution BaFe2(S1-xSex)3,
the orbital-ordering pattern switches from the ferroic one into the staggered one at thecritical concentration of the magnetic phase boundary, xc= 0.23, where the ground-statemagnetic structure switches from the striped-type one into the block-type one [3].
In this study, in order to clarify the details of the orbital ordering in the iron-based laddercompounds, we performed the electrical resistivity measurements under pressure for
BaFe2(S1-xSex)3. The measurements were
performed up to 2.0 GPa using a pistoncylinder high-pressure cell.
As a result, we found a distinct temperature
variation of the electrical resistivity below
and above 0.25 GPa for BaFe2(S0.75Se0.25)3(Fig. 1); on cooling, the electrical resistivity
sharply increases across the orbital orderingtransition (210-190 K) below 0.25 GPa, while
it shows a suppression of the divergent
manner across the orbital ordering transition(183-180 K) above 0.5 GPa. By referring toelectrical resistivity data at an ambientpressure, we conclude that the application ofpressure to BaFe2(S0.75Se0.25)3 induces theswitching of the orbital-ordering pattern fromthe ferroic one into the the staggered one. In
our poster presentation, we will show the)LJThe electrical resistivity
details of experimental results, and discuss
the origin of the pressure-induced orbitalof BaFe2(S0.75Se0.25)3
switching behavior.
[1] H. Takahashi, et al., Nat. Mater. 14, 1008 (2015).
[2] J. Ying, et al., Phys. Rev. B 95, 241109(R) (2017).
[3] S. Imaizumi, et al., Phys. Rev. B 102,035104 (2020).

114

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Dissipative particle dynamics approach to reaction-induced morphologicalchanges in thermoplastic/thermosetting resin mixtures
Yoshinori Tomiyoshi1*, Yutaka Oya1,2, Toshihiro Kawakatsu1 and Tomonaga Okabe3
1

Department of Physics, Graduate School of Science, Tohoku University
Department of Organic Materials Science, Graduate School of Organic Materials Science,
Yamagata University
3
Department of Aerospace Engineering, Graduate School of Engineering, Tohoku University
2

Control of microscopic structures of polymeric materials is of crucial importance indesigning various material composites. We utilize phase separating polymers such as diblock
copolymers as one of the promising tools to obtain a diversity of well-ordered microscopic
structures. Progress in computational techniques to correctly predict these structures including
molecular dynamics simulations or macroscopic continuum simulations is now strongly
desired.
In experimental point of view, Lipic et al.[1] showed a possibility of controlling mesoscopic
domain morphologies in thermoplastic/thermosetting resin mixtures. The morphologicalchanges observed in this system can be explained by reaction-induced phase separation where
the cross-linking of the matrix polymer leads to an instability of the microphase-separated
structures with a large mean curvature. Although this mechanism is expected to be a key to thecontrol of the microscopic structures, there have been few reports to understand the mechanism.
In the present study, we apply the dissipative particle dynamics (DPD) simulation, which
was proposed by Groot and Warren[2] to simulate microphase separation, tohomopolymer/diblock copolymer blends with a simple chemical reaction. In addition to their
original methodology, we incorporate the chemical reaction where homopolymers are
chemically connected with each other.
By conducting the simulation mentioned above, we reproduce the morphological changesof microscopic phase structures. Figure 1 shows a transition from cylindrical phase (Fig. 1 left)to lamellar phase (Fig. 1 right) due to the cross-linking of homopolymers. We also find that therate of polymerization reaction affects the structural order of the finally-obtained microphasestructures. This indicates the importance of the curing process in the control of domain
morphology.
Acknowledgements: Financial support from Cross-ministerial Strategic Innovation
Promotion Program (SIP) “Materials Integration for Revolutionary Design System of Structural
Materials” (Funding agency: JST) is gratefully acknowledged.
[1] P. M. Lipic, F. S. Bates, and M. A. Hillmyer, J. Am. Chem. Soc. 120, 8963 (1998).
[2] R. D. Groot and P. B. Warren, J. Chem. Phys. 107, 4423 (1997).

Fig. 1. Morphological change of the domain structure due to cross-linking
reaction. (Left) Cylindrical phase as the initial structure. (Right) Lamellar
phase as the final structure.

115

P-39

Solid Solution Strengthening and High-Temperature Strength in
TiC–TaC–ZrC–NbC Ceramics
D. Demirskyi1,2,3*, O. Vasylkiv2 and K. Yoshimi1,3
1

WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University
2
National Institute for Materials Science, NIMS, Tsukuba
3
Department of Materials Science and Engineering, Tohoku University

As an emerging concept in the field of metallic alloys, high-entropy (HE) materials
combine multiple principal elements to create new single-phase materials. Over the past few
years, the ‘HE strategy’ has been applied across various fields, including thermoelectricity,
catalysis and structural ceramics [1]. The large configurational entropy is believed to enhance
the simultaneous solubility of a large number of components, which can then be selected to
optimize target properties. However, medium-entropy compounds may emerge if a fewer
number of elements is being used. For these compounds, especially applied to ceramics, thegood balance of strength and hardness is being anticipated [2], as a lattice distortion is not as
severe as in HE case. Nevertheless, data on high-temperature strength is limited.
In this contribution, we explore synthesis of solid-solution of carbides, a medium-entropy(Ti1/4Ta1/4Zr1/4Nb1/4)C [3]. Bulk solid-solution or medium-entropy carbide ceramics have beenobtained by two different thermal histories using the spark plasma sintering method.
The mechanical performance at room temperature for the (Ti,Ta,Zr,Nb) carbides iscomparable to the best data for the TiC or TaC monolithic ceramics, reaching 600 MPa(Figure 1). This may be explained in terms of a solid-solution strengthening mechanism. In
terms of the specific flexural strength or specific stiffness, medium-entropy carbide bulks aresuperior to the majority of the monolithic carbides, except the TiC. Importantly, at elevatedtemperatures, medium-entropy (Ti,Ta,Zr,Nb) carbides possess the strength of 300 or 500 MPa
at 1600 °C where they fracture in an elastic manner [3]. The strength at high temperatures isquite sensitive to the consolidation conditions and is beyond a simple HE strategy andrequires further research.
[1] C. Oses, C. Toher, S. Curtarolo, Nat. Rev. Mater. 5 295–309 (2020).
[2] D. Demirskyi, H. Borodianska, T.S. Suzuki, Y. Sakka, K. Yoshimi, O. Vasylkiv, Scripta
Mater. 164 [15] 12–16 (2019).
[3] D. Demirskyi, T.S. Suzuki, K. Yoshimi, O. Vasylkiv, Open Ceramics 2 100015 (2020).

Fig. 1. Effect of the grain size and composition of
selected UHTCs normalized strength values [3].

116

P-40

Electrochemical characterization of Magnesium Borohydride Ammonia
Borane Mg(BH
as Magnesium
a Magnesium
Ionic Conductor
Electrochemical
characterization
BorohydrideAmmonia4)2(NH3BH3)2 of
Borane Mg(BH4)2(NH3BH3)2 as a Magnesium Ionic Conductor

Kazuaki Kisu1, Sangryun Kim2, Munehiro Inukai3, Hiroyuki Oguchi4,
1,2
3
and Shin-ichi
Orimo
Kazuaki Kisu1Shigeyuki, SangryunTakagi
Kim2,2,Munehiro
Inukai, Hiroyuki
Oguchi4,2
1,2
Shigeyuki Takagi , and Shin-ichi Orimo
1
WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University
2
1
Institutefor Materials
Research(IMR),
Tohoku University
WPI-Advanced
Institutefor Materials
Research(WPI-AIMR),
Tohoku University
3
2
Tokushima
University
Institute for Materials Research (IMR), Tohoku University
4
3
Shibaura
InstituteUniversityof Technology
Tokushima
4
Shibaura Institute of Technology
All-solid-state Mg batteries are one of the promising candidates for solving the intrinsic
drawbacksof Li-ion
as high
costpromisingand low abundancesources,theelectrolyte
All-solid-state
Mgbatteries,
batteries suchare oneof thecandidates offorLisolving
intrinsic
leakage,andlimitedenergydensity
[1].
For
the
developmentof
all-solid-state
Mg
batteries,
Mg
drawbacks of Li-ion batteries, such as high cost and low abundance of Li sources, electrolyte
ionic conductor
as solid
electrolytes
are Fora key
becausethe conductivity
and stability
leakage,and limited
energydensity [1].
thecomponent
developmentof all-solid-state
Mg batteries,
Mgof theconductor
solid electrolyte
performance.
this work,
we investigatedthe Mgionic
as solid determine
electrolytesbattery
are a keycomponentIn
becausethe conductivity
and stability
ionicand electrochemical
propertiesof the Mg(BH)2(NH3weBHinvestigated3)2 complex hydrideof theconduction
solid electrolyte
determine battery
performance.
In this4work,
the Mg[2]
toestablish
its
potential
applicability
inall-solid-state
Mg
batteries.
Followingthehydrideionic conduction and electrochemical properties of the Mg(BH4)2(NH3BH3)2 complex
mechanochemical
synthesis
of applicability
Mg(BH4)2(NHin3BH)2 and NHFollowing
3)2 from Mg(BH
3BH3, the Mg[2]
to establish its
potential
all-solid-state
Mg 4batteries.
the5
ionic conductivitiessynthesis
were determinedby4)2impedance
1.3 ×NH103−
S3, cmatmechanochemicalof Mg(BH(NH3BH3)2 measurementsfrom Mg(BH4as)2 andBH
the−1Mg
−5
−1
−5
−1
30
°C
and
8.4
×
10
S
cm
at
40
°C,
which
are
among
the
highestMg
ionic
conductivities
ionic conductivities were determined by impedance measurements as 1.3 × 10 S cm at
5−1
reporteddate× for
conduction
as shown
in Figure1 right.
In addition,
30°C andto8.4
10−solids
S cmwithout
at 40electron°C, whichare amongthe highest
Mg ionic
conductivities
cyclic voltammetry
investigations
a cell conduction
based on thiswith Mo
and Mgreported
to date for solids
without ofelectron
as material
shown incombined
Figure 1 right.
In addition,
electrodes
showed thatMg stripping
occurred
at 0 Vcombined(relative withto theMo
Mg
metal
cyclicvoltammetry
investigationsof aandcellplatingbased onthis materialandMg
electrode)
as
shown
in
Figure
1
left.
These
results
therefore
confirm
that
Mg
ionic
conduction
electrodes showed that Mg stripping and plating occurred at 0 V (relative to the Mg metal
can be achieved
by in
theFigurecoordinationof NHresults
to Mg(BHconfirm
it isMg
expected
that these3BH3 therefore
4)2, andthat
electrode)as shown
1 left. Theseionic conduction
observations
will bycontributeto the development
all-solid-state[3]. that thesecanbe achieved
the coordinationof NH3BHof
Mg(BH4)2, Mg
and batteries
it is expected
3 toobservations
will
contributetothedevelopmentof
all-solid-state
Mg
batteries[3].
This work was supported by MEXT, KAKENHI (JP18H05513 (Hydrogenomics),
19K15305,
and was
19K15666).
This work
supported by MEXT, KAKENHI (JP18H05513 (Hydrogenomics),
19K15305,
and
19K15666).
[1] J. Muldoon et al., Chem. Rev., 114 (2014), 11683.
[2]
X.Muldoon
Chen et al.,DaltonTrans.,
14365.
[1] J.
et al.,
Chem.
Rev., 42
114(2013)(2014),
11683.
[3] X.
K. Chen
Kisu etetal.,
Appl.
Energy3 (2020) 3174.
[2]
al.,ACS
DaltonTrans.,
42 Mater.,(2013) 14365.
[3] K. Kisu et al., ACS Appl. Energy Mater., 3 (2020) 3174.

Fig. 1. Temperature dependence of the Mg2+ ionic conductivity of Mg(BH4)2(NH3BH3)2 withthose of previously
reported
complexhydrideMg-ion conductors
CyclicFig. 1. Temperaturedependenceof theMg2+ ionic
conductivityof Mg(BH(Left).
4)2(NH
3BH3)2 with
/Mo at 30°C, at a scan
rateCyclicof 10 mV s
voltammogramsof Mg/Mg(BH4)2- (NH3BH3)2Mg-ion
thoseof previously
reported complex
hydrideconductors(Left).
−1
2+
,
and
with
use
of
a
voltage
range
of
−0.5
to
1.0
V
vs.
Mg
/Mg
(Right).
voltammograms of Mg/Mg(BH4)2- (NH3BH3)2/Mo at 30 °C, at a scan rate of 10 mV s
−1
, and with use of a voltage range of −0.5 to 1.0 V vs. Mg2+/Mg (Right).

117

P-41

Two dimensional bio-hybrid membranes based on self-assembly
Teng Ma1
1

WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University

The bilayer lipid membrane (BLM), a basic structure in cell membranes, is a selfassembled structure of phospholipid molecules. Benefit from unique properties, such as
ultrahigh resistance, thin thickness (3~4 nm), and amphiphilicity, BLMs have been widelyused as platforms to explore physiological and pharmaceutical applications by monitoringtransmembrane transport process. Recently, the combination of BLMs and nanocarbon
materials has attracted significant attention as novel devices. In this work, we functionalized
the BLMs using organic molecules such as [6,6]-phenyl-C61-butyric acid methyl ester(PCBM), and Copper(II) 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine (CuPc), anddemonstrated that the functionalized BLMs could be used as a platform for sensing devices.
Firstly, when free standing BLMs were doped with PCBM molecules, a photo-inducedchange in transmembrane conductance was observed [1]. The light illumination reversibly
switched the membrane conductivity that was induced only when BLMs were doped with
PCBMs. In order to further improve the performance of BLM-based devices, we introduced a“gate bias” to the free standing BLM system [2]. We fabricated a Si chip equipped with two
metal electrodes as the support for BLMs. When the lateral bias was applied to the twoelectrodes on the Si chip, the PCBM-doped BLM showed photoresponse under lightillumination and lateral bias. We were able to modulate the transmembrane current bychanging the lateral bias. These results indicate that the BLM is a promising platform forhybrid nanodevices. To further expand the range of application of BLMs to solid-state
devices, hybrid membranes consisting of lipid molecules and organic molecules, namely,
CuPc were formed through self-assembly at a water/air interface [3]. We demonstrated that a
hybrid membrane with a large area can be obtained by simply transferring the self-assembled
membrane onto a Si substrate (Fig. 1). These results demonstrated that the hybrid BLM is a
powerful and feasible platform for realizing sensing devices.
[1] K. Kanomata, T. Deguchi, T. Ma, T. Haseyama, M. Miura, D. Yamaura, D. Tadaki, M.
Niwano, A. Hirano-Iwata, F. Hirose, J. Electroanal. Chem., 832, 55 (2019).
[2] T. Ma, X. Feng, T. Deguchi, T. Ohori, D. Yamaura, R. Miyata, D. Tadaki, M. Komiya, K.
Kanomata, F. Hirose, M. Niwano, A. Hirano-Iwata, ACS Omega, 4, 18299 (2019).
[3] X. Feng, T. Ma, D. Yamaura, D. Tadaki, A. Hirano-Iwata, J. Phys. Chem. B, 123, 6515
(2019).
[4] X. Feng, T. Ma, D. Tadaki, A. Hirano-Iwata, J. Vis. Exp. 159. E60957 (2020).

(a)

(b)

Fig. 1. Formation method (a) and structure illustration (b) of the CuPc-doped BLMs.

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In-situ low-temperature scanning tunneling microscopy and spectroscopy
studies of SrVO3 and Pr thin films
Hirofumi Oka1 and Tomoteru Fukumura1,2
1

WPI-Advanced Institute for Materials Research (WPI-AIMR) and Core Research Cluster for
Materials Science, Tohoku University
2
Department of Chemistry, Graduate School of Science, Tohoku University

Nano-scale electronic materials, such as ultrathin films and nanostructures, are expected to
exhibit novel quantum electronic properties paving the way to new functional electronic
devices. In order to explore their novel electronic properties, it is crucial to characterize
nano-scale materials on the atomic scale. Scanning tunneling microscopy and spectroscopy(STM and STS) are powerful techniques to investigate local atomic structures and electronic
properties of nano-scale materials due to their high spatial resolution. Here, we report recent
results of SrVO3 ultrathin films on SrTiO3 (001) and Pr thin films on CaF2 (111) obtainedusing low-temperature STM equipped with pulse laser deposition (PLD).
Figure 1(a) shows a topographic STM image of SrVO3 ultrathin films. Previously, we
revealed that the surface reconstruction played an important role in the formation of metallic
surface states of SrVO3 [1]. We further investigated impact of dimensionality on theelectronic states of SrVO3 and revealed that the electronic states of SrVO3 nanowires changed
from metallic to insulating with decreasing the nanowire width [Fig. 1(b)]. We ascribed thisnew kind of a metal-insulator transition to dimensional crossover mechanism [2,3].
Another observation is concerned with fcc-structure Pr thin films on CaF2 (111) deposited
by PLD in vacuum, which is intriguingly one of high-pressure phases of Pr, probably
exhibiting delocalized 4f electronic states. However, there has been no experimental report todirectly corroborate delocalization of 4f electrons in high-pressure phase Pr. Figure 1(c)shows an STM image of the Pr thin films. We found a spatial modulation of differential
conductance at step edges and around defects [Figs. 1(d) and (e)]. This is a clear indication of
the existence of itinerant electrons in the high-pressure phase Pr, which is probably the firstexperimental evidence of delocalized 4f electronic states.
These studies are in collaboration with T. Hitosugi (AIMR, Tokyo Tech.), Y. Okada(AIMR, OIST), K. Kaminaga (AIMR), and D. Oka (Dept. Chemistry).
[1] H. Oka, Y. Okada, T. Hitosugi, and T. Fukumura, Appl. Phys. Lett. 113, 171601 (2018).
[2] H. Oka, Y. Okada, K. Kaminaga, D. Oka, T. Hitosugi, and T. Fukumura, Appl. Phys. Lett.
117, 051603 (2020).
[3] AIMResearch, 26 Oct. 2020.
(b)

(a)

(c)

(d)

50 nm

2 nm

(e)

(√5×√5)-R26.6°
nanowires(√2×√2)-R45°

10 nm

Fig. 1. (a) SrVO3 ultrathin films deposited on SrTiO3 (001). (b) Zero-bias
conductance (ZBC) of nanowires as a function of the width. (c) Pr thin films
deposited on CaF2 (111). (d) and (e) Topographic and differential conductancemaps around a step edge of Pr thin films (sample bias voltage V = −10 mV).

119

P-43

Phase Separation with Ordering in Aged Fe-Ni-(Al,Mn) Alloys
Fei Sun 1, Goro MIYAMOTO 2 and Tadashi FURUHARA 2
1 WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University
2 Institute for Materials Research (IMR), Tohoku University

High entropy alloys (HEAs) are presently of great research interest in materials science andengineering. Stability of solid solution is affected by high entropy due to multi-component
and high alloyed natures and also by complex mixing enthalpy due to various elemental
interactions. This study aims to re-analyze effects of elemental interactions on decompositionof solid solution, such as ordering and phase separation, in model high alloys in ternary
systems. Fcc based Fe-Ni alloys were selected since the most popular fcc HEA alloys containboth Fe and Ni as its constituents [1]. An additional third element, Mn or Al, was chosen. Mn
is another element in the fcc HEA and Al gives a variety of phase separation [2].
The alloys Fe-35at.% Ni-10at.% Al and Fe-35at.% Ni-35at.%Mn were prepared by arc
melting method. Hot forging and hot rolling were performed around 1300℃. Homogenization
treatment was carried for 96h at 1150℃. Solution treatment was conducted for 1h at 1200℃.
Aging treatments were performed at 400℃~800℃ for various times. Atomic-scaled orderingand elements distribution behaviors were analyzed by Cs-corrected STEM and 3DAP.
Fe-35Ni-10Al alloys presented the peak hardening at 700℃ and the hardness is slightly
increased after aging at 500℃ (Figure 1 (a)). Atomic structure of L12 ordered phases andelements slight fluctuations were presented in Figure 1 (b). Fe-35Ni-35Mn alloys showed thepeak hardening after aging at 500℃ (Figure 1 (c)). Atomic structure of L10 ordered phases
were also detected after aging at 500℃ for 96h in Figure 1 (d). Each particle is notdistinguishable and composition fluctuation resembles spinodal decomposition. Furthermore,enrichment of Al/Mn and Ni and depletion of Fe at the same place are detected. Highfrequency of simultaneous depletion/enrichment of Al/Mn and Ni atoms also support cosegregation of Al/Mn and Ni atoms. Those results imply that fcc lattice is decomposed via
spinodal ordering toward the formation of L12/L10 phases.

Figure 1. (a) Hardness after aging and (b) superposition of HAADF-STEM image and EDS
mapping after aging at 500℃/30h of Fe-35Ni-10Al (at.%) alloys, (c) hardness after aging and(d) superposition of HAADF-STEM image and EDS mapping after aging at 500℃/96h of
Fe-35Ni-35Mn (at.%) alloys.
[1] Cantor et al.: Mater. Sci. Eng. A, 375, 213 (2004).
[2] He et al. : Acta Mater., 62, 105 (2014).
[3] Sun et al.: JIM 2020 spring meeting abstract, S1.17.

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121

Project Introduction of
the Core Research Cluster
for Materials ScienceP-45

The Core Research Clusters for Materials Science-Advanced Energy MaterialShin-ichi Orimo1,2 and Kazuaki Kisu1
1

WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University
2
Institute for Materials Research (IMR), Tohoku University

This project aims highly efficient energy conversion and storage systems for hydrogenenergy based autonomous society. In this project, we systematically study the materials
science relating to electricity generation from renewable energy using solar cell andspintronics materials, and that from hydrogen using high-performance fuel Cell materials, andalso energy storage using some hydrogen Production/Storage Technologies and High-Safety
Battery Materials (Fig.1). To realize the system and society, we are working on this projectwith all Tohoku university organizing by Prof. Orimo (AIMR・IMR), Prof. Samukawa(AIMR・IFS), Prof. Suito (AIMR), Prof. Mizuguchi (IMR), Prof. Amezawa (IMRAM), Prof.
Honma (IMRAM), Prof. Tokumasu (IFS), Prof. Takamura (Graduate School of Engineering),
Prof. Wadayama (GSES), and Prof. Yumoto (IMR). As recent achievements, we reported
papers regarding lithium-ion solid electrolyte [1], proton conductors [2, 3], electrochemical
CO2 reduction reaction [4], biocompatible batteries [5], and low-temperature plasma scienceand technology [6]. While continuing to look at applications for practical devices andsystems, we will aim to develop leading-edge energy materials for energy generation, storage,
conversion, and use.
[1]. S. Kim, H. Oguchi, N. Toyama, T. Sato, S. Takagi, T. Otomo, D. Arunkumar, N. Kuwata,J. Kawamura and S. I. Orimo, Nat. Comm., 10, 1081 (2019).
[2]. H. Takahashi, I. Yashima, K. Amezawa, K. Eguchi, H. Matsumoto, H. Takamura, S.
Yamaguchi, Chem. Mater., 29, 1518 (2017).
[3]. T. Nakamura, S. Mizunuma, Y. Kimura, Y. Mikami, K. Yamauchi, T. Kuroha, N.
Taniguchi, Y. Tsuji, Y. Okuyama and K. Amezawa, J. Mater. Chem. A, 6, 15771 (2018).
[4]. N. Todoroki, H. Tei, H. Tsurumaki, T. Miyakawa, T. Inoue, T. Wadayama, ACS
Catalysis, 9, 1383 (2019).
[5]. S. Stauss and I. Honma, "Bull. Chen. Soc. Jpn. (Accounts & Reviews)", 91, 492 (2018).
[6]. W. Mizubayashi, S. Noda, T. Nishi, A. Kikuchi, H. Ota, PH. Su, YM. Li, S. Samukawa,
and K. Endo, Appl. Phys. Express, 10, 26501 (2017).

Figure 1. High-Efficient Energy Conversion & Storage Systems for Hydrogen-Energy
Based Autonomous Society

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Advanced Electronic Materials Projectin Core Research Cluster of Material Science
Tomoteru Fukumura1,2 and Hirofumi Oka1
1

WPI-Advanced Institute for Materials Research (WPI-AIMR) and Core Research Cluster,
Tohoku University
2
Department of Chemistry, Graduate School of Science, Tohoku University

In this project, new scientific principles and novel materials/properties/functionalities inadvanced electronic materials are explored via state-of-the-art material synthesis andmeasurement techniques for bulk crystals, thin films, nanostructures, and heterointerfaces ofinorganic/organic/hybrid compounds. Through these researches, we aim to develop new
research fields as well as applications such as energy saving, generation, and storage.
Our recent achievements are concerned with elucidation of crystal growth dynamics of
GaSb crystal [1], discovery of near-room temperature ferromagnetic semiconductor [2], thinfilm growth of quantum spin honeycomb IrO6 structure [3], synthesis of hazardous
element-free quantum dot phosphors [4], development of highly efficient n-type organic
thermoelectric [5], electronic/ionic conduction switching in n-type organic semiconductor [6],and development of vacuum process for ionic liquid nano-gel film [7], in addition to
construction of electronic phase diagram for ladder type iron based superconductor [8],enhancement of Curie temperature in 2D topological material [9], and transformation of
conventional superconductor into topological superconductor [10].
This project members are currently composed of Profs. Yong P. Chen (WPI-AIMR/Purdue
Univ.), Takafumi Sato (WPI-AIMR/Physics), Kenya Ohgushi (Physics), Kazuo Takimiya(Chemistry), Yuji Matsumoto (Applied Chemistry), Atsushi Tsukazaki (IMR), Kozo Fujiwara(IMR), Tomoyuki Akutagawa (IMRAM), Takahisa Omata (IMRAM), and Hiroshi Suito(WPI-AIMR). By strengthening intra-university network, advanced electronic materials are to
be developed.
[1] K. Shiga, M. Kawano, K. Maeda, H. Morito, and K. Fujiwara, Scr. Mater. 168, 56 (2019).
[2] T. Yamamoto, K. Kaminaga, D. Saito, D. Oka, and T. Fukumura, Appl. Phys. Lett. 117,052402 (2020).
[3] K. Miura, K. Fujiwara, K. Nakayama, R. Ishikawa, N. Shibata, and A. Tsukazaki,
Commun. Mater. 1, 55 (2020).
[4] S. Tsukuda and T. Omata, J. Soc. Inf. Disp. 28, 680 (2020).
[5] Y. Wang and K. Takimiya, Adv. Mater. 32, 2002060 (2020).
[6] H. Abe, A. Kawasaki, T. Takeda, N. Hoshino, W. Matsuda, S. Seki, and T. Akutagawa,
ACS Appl. Mater. Interf. 12, 37391 (2020).
[7] H. Watanabe, R. Takazawa, R. Takahaashi, S. Maruyama, and Y. Matsumoto, ACS Appl.
Nano Mater., accepted (2020).
[8] S. Imaizumi, T. Aoyama, R. Kimura, K. Sasaki, Y. Nambu, M. Avdeev, Y. Hirata, Y.
Ikemoto, T. Moriwaki, Y. Imai, and K. Ohgushi, Phys. Rev. B 102, 035104 (2020).
[9] H. Idzuchi, A. E. Llacsahuanga Allcca, X. C. Pan, K. Tanigaki, and Y. P. Chen, Appl.
Phys. Lett. 115, 232403 (2019).
[10] C. X. Trang, N. Shimamura, K. Nakayama, S. Souma, K. Sugawara, I. Watanabe, K.
Yamauchi, T. Oguchi, K. Segawa, T. Takahashi, Y. Ando, and T. Sato, Nature Commun.
11, 159 (2020).

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Next-generation medical diagnosis and treatment based on
bio-hybrid materials and devices
Teng Ma1,2, Ayumi Hirano-Iwata1,3
1

WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University
2
Core research cluster for materials, Tohoku University
3
Research Institute of Electrical Communication (RIEC), Tohoku University

As one of the five core materials research clusters of the Designated National University
programme in Tohoku University, the goal of the biomaterial research cluster is to achieve
basic technologies in support of leading-edge medical care, and to create highly functional
biomaterials and devices. By fusing biomaterials and nanotechnology, we seek to create
bio-hybrid materials and devices equipped with advanced functions, which are not possible
with biomaterials or artificial materials on their own, and to extend these to technologies fordiagnosis and treatment. We will contribute to the realization of future medical care from theviewpoint of materials science by forming alliances with researchers in related areas in Japanand abroad, and through collaboration with mathematical science. We seek to create newfunctional biomaterials for future medical care with the aim of realizing SDG 3, “Good healthand well-being,” as well as to contribute to SDG 9, “Industry, innovation and infrastructure,”
and SDG 12, “Responsible consumption and production.”In the past two years, we devoted to realize the former mentioned goal of the core researchcluster of biomaterials and made significant progresses. For example, we developed totallyorganic stretchable electrochromic to realize skin patch for wound healing and drug dosing[1], fabricated honeycomb films by the breath figure technique and examine their applications
in various fields [2], and investigated the impact of modular organization on dynamicalrichness in cortical networks and its effect on neural networks [3]. Toward the final goal ofthis programme, we are marshaling the comprehensive research capability of Tohoku
University as a whole to develop unprecedented highly functional biomaterials.
[1] H. Kai, W. Suda, S. Yoshida, M. Nishizawa, Biosensors. Bioelectron. 123, 108 (2019).
[2] H. Yabu, Sci. Technol. Adv. Mater. 19, 803 (2018).
[3] H. Yamamoto, S. Moriya, K Ide, T. Hayakawa, H. Akima, S. Sato, S. Kubota, T. Tanii,
M. Niwano, S. Teller, J. Soriano, A. Hirano-Iwata, Sci. Adv. 4, eaau4914 (2018).

Drug

Measurement for
diagnosis

Measurement fortreatment
Realizing future
medical care

Creation of bio-hybridmaterials

Design for treatment

Development oftreatment technology

Fig. 1. The main goal and approaches of the core research cluster of biomaterials.

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P-48

Strengthening by metastable solute clustering/precipitation
in low-alloy nitrogen steels
Tadashi Furuhara1,2, Mitsutaka Sato2 and Goro Miyamoto2, 31Core Research Clusters for Materials Science, Tohoku University
2
Institute for Materials Research, Tohoku University
3
Research Center for Structural Materials, National Institute for Materials Science

Nitrogen (N), another major interstitial element other than carbon (C), can be utilized instrengthening of steels. When nitrogen has a strong attractive interaction with substitutional
solute element in iron, precipitation of nanoscale solute clusters prior to alloy nitride
precipitation, resulting in extraordinary large strengthening [1, 2]. Such metastable soluteclusters are formed by phase separation coupled with ordering interstitial element (i) andsubstitutional element (s). However, the process of N-s solute cluster formation and transition
to stable alloy nitride is not clearly understood in atomic scale. In our group, advanced
nanoscale characterization techniques, such as Cs-corrected HAADF-STEM and3-Dimenional Atom Probe, have been applied to examine precipitation behaviors in nitridingof ferritic steels or tempering of martensitic steels containing substitutional solute elements.
During the high-temperature tempering of Fe-0.3mass%N martensite with addition of Cr, Mo,or Mn by 1mass%, resistance to temper softening is clearly observed [3]. In particular,
secondary hardening occurs with Cr or Mo addition. In early stage of tempering, monolayer
metastable clusters are formed within the martensite as well as heterogeneous precipitation of
stable B1-type alloy nitride at defects such as grain boundaries. As tempering is prolonged,
the alloy cluster increase its thickness and changed to B1-type nitride, resulting in further
increase of hardness. With Mn addition, B1-type Mn nitride was detected, which presumably
changes to stable -Mn3N2 having a larger hexagonal unit cell by thickening.
Large strengthening with nanosized precipitation of alloy nitrides, which are hard particles,
implies operation of Ashby-Orowan dispersion strengthening mechanism. We are now
examining the relationship between strengthening and metastable clustering in nitrided Fe-Ti
alloys [4] and results obtained will be also discussed.
[1] T. Furuhara: Ferrum, 25(2020), pp. 506-512.
[2] G. Miyamoto et al., Mater. Sci. Technol. , 27(2011), 742.
[3] S. -W. Young et al: submitted to Acta Materialia, 2020.
[4] K. Itasaka et al.: CAMP-ISIJ, 33(2020), 587.

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P-49

Overview of the High-Strength Materials Project
D. Demirskyi1,2*, and K. Yoshimi1,2
1

1WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University
2
Department of Materials Science and Engineering, Tohoku University

This contribution introduces the high-strength materials project which was initiated in theframework of the research activities of the Tohoku University.
We consider the advanced control over synthesis, evaluation, and testing technologies andtheir fusion with modeling as the main idea behind the project. Fulfilment of these ideas are
required to enhance and pioneer new class of ultra-high temperature materials with improved
strength and ultimate heat-resistant properties as result of flexible microstructure control.
Crucially, by extending interdisciplinary nature of the graduate school educational systemwith ideas, methods and technologies developed within the project, we attempt to establish aworld premier research and educational center for high-strength materials drawing on thehistory and traditions of Tohoku University.
Currently, our joint efforts [1–3] are being devoted to fusion of ideas between metallurgy
and ceramic science in order to create and characterize novel high-temperature alloys,
high-temperature ceramics, and composites.
[1] D. Demirskyi, T.S. Suzuki, K. Yoshimi, O. Vasylkiv, Open Ceramics 2 100015 (2020).
[2] H. Fukuyama, M. Ohtsuka, R. Sawada, H. Nakashima, Y. Ohishi, N. Hirao, M. Tanaka, K.
Yoshimi, Materialia 13 100867 (2020).
[3] W. Zhou, K. Kikuchi, N. Nomura, K. Yoshimi, A. Kawasaki, Materialia 10 100655(2020).

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P-50

Endothelial Cells Distribution on the Stent Strut with Surface Treatment
after the Flow Exposure
Zi Wang1,2, Narendra Kurnia Putra3, Kako Yamasaki4, Naofumi Ohtsu4, Hisatoshi
Kobayashi5, and Makoto Ohta1
1

Institute of Fluid Science, Tohoku University, Japan
Graduate School of Biomedical Engineering, Tohoku University, Japan
3
Instrumentation and Control Research Group, Faculty of Industrial Technology, Institut
Teknologi Bandung
4
School of Earth, Energy and Environmental Engineering, Kitami Institute of Technology,
Japan
5
WPI-MANA, National Institute for Materials Science, Japan
2

With the rapid development of stent technology, stent implantation is now becoming one of
the main treatments for cardiovascular diseases, such as stenosis and aneurysm [1]. However,the damage on the endothelial cells (ECs) layer could lead to chronical complications such as
in-stent restenosis (ISR), neointimal hyperplasia and thrombosis are because of theintravascular blood flow disturbed by the structure of stent struts [2].
Previous studies found that ECs could response to the wall shear stress (WSS) sensitively by
causing their morphological and physiological changes [3]. And ECs could suppress the
neointima formation. Therefore, the clinical complications after stent deployment could beconsidered as the endothelial cells dysfunction around the stent struts or insufficientendothelialization.
In this study, to observe whether the surface treatment method could promote theendothelialization. Moreover, many researches were conducted under static state. Because ECs
are sensitive to flow and WSS, ECs distribution on the stent strut with different surface
treatment is necessary to investigate under the flow exposure.
A parallel flow chamber was designed to produce constant WSS on ECs monolayer to makethe flow effect clear. A straight NiTi stent strut with surface treatment of collagen coating or
anodizing was placed above the ECs layer. ECs were exposed to flow for 24 h under 2 Pa WSS
condition, which is a normal condition in human. Then, ECs distribution on the surface of stent
strut were observed. To understand the WSS distribution inside the flow chamber,computational fluid dynamics (CFD) simulation was used.
After 24 h exposure to the flow, ECs density on the downstream surface of stent strut ishigher than the density on the upstream surface. ECs density on the stent strut with surface
treatment is higher than the stent strut without any surface treatment. CFD results show the flow
recirculation near the downstream side of stent strut.
The stent with surface treatment such as collagen coating and anodizing may could promote
the process of endothelialization.
[1] W. S. Aronow and J. A. Mcclung, Translational Research in Coronary Artery Disease:
Pathophysiology to Treatment (Academic Press, 2015).
[2] J. E. Cohen, J. M. Gomori, S. Moscovici, R. R. Leker, and E. Itshayek, Delayed
Complications after Flow-Diverter Stenting: Reactive in-Stent Stenosis and Creeping
Stents, Journal of Clinical Neuroscience 21, 1116 (2014).
[3] H. Anzai, T. Watanabe, X. Han, N. K. Putra, Z. Wang, H. Kobayashi, and M. Ohta,
Endothelial Cell Distributions and Migration under Conditions of Flow Shear Stress arounda Stent Wire, Technol Health Care 28, 345 (2020).

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Evaluation and Sensing Project - support through collaboration between
microscopic analysis, measurements and evaluation infrastructureMasami Terauchi**

Institute of Multidisciplinary Research for Advanced Materials, Tohoku University.

To aid development of advanced materials
going beyond traditional performance
limits, we are aiming to form ameasurement and evaluation infrastructure
network around the core technologies of
microscopic analysis and three-dimensional
visualization.
In support of effective and efficientmaterials development, we will facilitate
collaboration between researchers involved
in development and application of analysis
technologies, with microscopic analysis ascore, and technical staff managing theshared equipment infrastructure formeasurement and evaluation, while having
coordinators match measurement andFigure 1. Core members of Evaluation and Sensing
Project.

Figure 2. Evaluation and Sensing Project Concept.

analysis technologies tothe needs of thoseengaged in developmentof materials.
Briefing sessions on
analysis techniques andmatching consultations
have been held sometime
according to demands ofmaterials scientists [1].
Pushing the limit of anevaluation method [2]andcollections
onexperimental data of new
analysis applications as adata base are ongoing[3].

[1] H. Morito, S. Shibano, T. Yamada, K. Ikeda, M. Terauchi, R.V. Belosludov and H.
Yamane, Solid State Sciences 120, 106166-1-5 (2020).
[2] M. Terauchi, T. Hatano, M. Koike, A.S. Pirozhkov, H. Sasai, T. Nagano, M. Takakura andT. Murano, IOP Conf. Series: Materials Science and Engineering 891, 012022-1-11(2020).
[3] M. Terauchi, H. Takahashi, M. Takakura, T. Murano, and S. Koshiya, “Handbook of Soft
X-ray Emission Spectra ver.6.0” (Aug. 2020).

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Process Science Toward Design and Control of Nanomaterials
Akira Yoko1, Gimyeong Seong2, Takaaki Tomai3, Tadafumi Adschiri*1,2,3
1

WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University
New Industry Creation Hatchery Center, Tohoku University, Sendai 980-8579, Japan
3
Institute of Multidisciplinary Research for Advanced Materials, Sendai 980-8577, Japan,*Email: tadafumi.ajiri.b1@tohoku.ac.jp
2

To achieve fine control and design of nanomaterials, processing of nanomaterials arefocused on. Process science [1] toward the construction of platform for the nanomaterial
engineering is introduced.
Nanoparticles behave as monomers like molecules in various processes, and it is crucial toestablish “thermodynamics of nanoparticles” including the phase behavior (dispersive andaggregative) and transport property (diffusion, viscosity, thermal conductivity). Dispersive
behavior of organic modified nanoparticles in organic solvents was studied using solubility
parameter. Microscopic phenomenon such as incorporation of solvent molecules into organic
modifier layer was found to affect the dispersibility of nanoparticles. Transport properties ofnanoparticles such as diffusion, viscosity, and thermal conductivity was studied relating to its
phase behavior. Structural formation such as nucleation, growth, and crystallization can beunderstood based on these fundamental properties and analogy of conventional molecularsystem.
Toward engineering of nanomaterials, unit operations of nanomaterials such as synthesis,
separation, and assembly of nanoparticles should be considered as conventional chemical
processes of molecular system. Progress of “Process Science” project is introduced in thispresentation.
[1] A. Yoko, G. Seong, T. Tomai, T. Adschiri, Acc. Mater. Surf. Res. 5 (3), 43-50 (2020).

Fig. 1. Schematic diagram of “Process Science” project [1]

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Formation of the global human resources development base
- Introduction of International Joint Graduate Program in Materials
Science K. Katagiri1*, Y. Yoshioka1 and K. Oikawa1
1

International Joint Graduate Program in Materials Science, Tohoku University

The aim of our group will develop the global human resources development base in theCore Research Cluster for Materials Science together with the International Joint Graduate
Program in Materials Science (GP-MS) as shown in Fig. 1. In this presentation, we will
introduce about the details of GP-MS. GP-MS program offers opportunities to study leading
research and technologies in the world in order to develop researchers and engineers capableof leading innovations in global material science and engaging powerfully with theinternational community. Students in this program will take 4 main subjects; Material Science
International, Materials Science Practice, Practical language skills and Materials Science
Special Seminar which give them valuable learning and experiences. This program also hasvarious assistance, such as financial support and support for travelling overseas, so thatstudents can concentrate on their studies.

Fig.1 The structure of Education and Human Resources development in Materials science131

Poster Abstracts:
GP-MS

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Properties of Primitive Membrane andOptimization of Biopolymers in Life Evolution
Akiko Baba1*, Ulf Olsson2 and Masayuki Imai1
1

2

Department of Physics, Tohoku University
Depertment of Physical Chemistry, Lund University

Fatty acid, one of simplest component of cellular membrane, is thought to be a key
material bridging material world and biological world. In this study, we show various patternsof growth of fatty acid vesicle, which is cellular membrane-like spherical structure, undercontinuous supply of material resources [2]. A life is a system that (i) taking in material andenergy sources from environment, (ii) synthesizing proteins based on genetic information
molecules and (iii) replicating the information molecules and biological membrane using
functional protein. Concerning from non-living molecular assemblies to cellular life,
interplay between biopolymers such as proteins and information molecules and vesicles thatare container of biopolymers is essence. In the prebiotic era, it is likely that oligonucleotides
or oligopeptides encourage growth and division of primitive fatty acid vesicles. Fatty acid is
a carboxylic acid with a long hydrocarbon chain, and is thought to have worked as membranein the birth of life. Decanoic acid, one of fatty acid, stably forms vesicles around at pH 7 inaqueous solution [3]. In previous researches, it has been reported that certain amino acids andbases bind to decanoic acid, and enhance stability of vesicles against salt [4][5]. However, theproperties of fatty acid as vesicle and interplay between fatty acid and prebiotic materials in
prebiotic self-reproduction system are still unclear.
Therefore, we investigated the effect ofprimitive molecules on the growth of vesicle,
and then clarified them by the growth rate.
The vesicle growth rate probably depends on
the sequence of nucleotides or amino acids,
which determine “fitness landscape” toward
the cellular life (Fig.1). Our results imply thatgene and protein expression might have been aresult of selective linked sequence andpolymerization degree of bases and aminoacids toward superior catalyst to the growth.

Fig. 1. Illustration of Fitness Landscape[2] T.F. Zhu, and J. W. Szostak, J. Am. Chem. Soc. 131, 15, 5705-5713 (2009).
[3] R. Wick, P Walde, and P.L. Luisi, J. Am. Chem. Soc. 117 , 1435-1436 (1995).
[4] C.E. Cornell, R. Black, M. Xue, H.E. Litz, A. Ramsay, M. Gordon, A. Mileant, Z.R.
Cohen, J.A. Williams, K.K. Lee, G.P. Drobny, and S.L. Keller, Proc. Natl. Acad. Sci. U.S.A.
116, 17239-17244 (2019).
[5] R.A. Black, M.C. Blosser, B.L. Stottrup, R. Tavakley, D.W. Deamer, and S.L. Keller,
Proc. Natl. Acad. Sci. U.S.A. 110, 13272-13276 (2013).

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Development of Microfluidic Device for Planar Assembly of Giant Vesicles
T. Chiba1, H. Sugiyama2, T. Toyota2 and M. Imai1
1

2

Graduate School of Science, Tohoku University
Graduate School of Arts and Science, The University of Tokyo

In multi-cellular organism, cellular membrane morphology plays a key role that connects
between cell shape mechanics and cellular functions. To extract minimal essence of therelationship, we have investigated morphology of the giant vesicle (GV: shell structurecomposed of lipid bilayer) assemblies as a model of multi-cellular organism [1, 2]. The GV
doublet, the simplest GV assembly, shows characteristic morphology transitions by varying thevolume to area ratio and adhesion strength. In this study, we extend this result to larger-scale
GV assemblies composed of tens GVs. For this purpose, we have been developing a
microfluidic device that extracts GVs having the same size from polydisperse mother GVsuspension and forms planar and monodisperse GV assemblies. Design of our microfluidic
device is based on a deterministic lateral displacement technique developed by Huang’s group.
[3, 4]. In preliminary experiments, we have succeeded in forming the planar assemblies
composed of ~ 20 GVs with a 20 m radius. This is a first step to construct the biomimetic
platform for multi-cellular organism.
[1] Y. Sakuma, M. Imai, M. Yanagisawa and S. Komura, Eur. Phys. J. E, 25, 403-413 (2008)[2] K. Murakami, R. Ebihara, T. Kono, T. Chiba, Y. Sakuma, P. Ziherl and M. Imai, Biophys.
J. (2020) DOI: https://doi.org/10.1016/j.bpj.2020.09.030[3] L. R. Huang, E. C. Cox, R. H. Austin and J. C. Sturm, Science., 304, 987-990 (2004)[4] Y. Kazayama, T. Teshima, T. Toshihisa, S. Takeuchi and T. Taro, Anal. Chem., 88, 11111116 (2016)

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Promotion of DNA Synthesis by Liposome Surface
Yuto Hachiya1*, Hikaru Hatori1 , Shoichi Toyabe2 Steen Rasmussen3 and Masayuki Imai1
1

Department of Physics, Tohoku University*,
Department of Applied Physics, Tohoku University
3
Department of Physics, Chemistry and Pharmacy, University of South Denmark
6-3 Aoba, Aramaki, Aoba, Sendai 980-8578, Japan2

DNA is a molecule which can retain information by 4 kinds of bases and accurate DNA
synthesis is very important for many fields. Templated ligation reaction is the connection of
two DNAs which bind to one DNA called template strand and base sequences can be produced
exactly by this reaction. But the reaction proceeds ineffectively in bulk because each DNA
diffuses 3-dimensionally in random direction.
To solve this problem, We propose the way to accelerate templated ligation reaction of DNA
which have hydrophobic segment on liposome surface. Liposome is the spherical lipid bilayer
like cell membrane and on liposome surface, hydrophobic molecules aggregate and diffuse 2dimensionally due to the high fluidity of liposome surface. So it is expected thathydrophobically-modified DNAs become dense and collide each other frequently on liposome
surface and reaction is promoted (Fig.1). To confirm this hypothesis, we estimated the rate of
DNA synthesis on liposome surface by fluorescent dye and compared it to the mathematicalmodel we made. As a result, it was unveiled that liposome surface promotes the DNA synthesis
highly.
This method is very effective and reasonable way to synthesize DNA and even make itpossible to create new material. In fact, DNA-liposome complex is used as a nanomaterial inbioengineering, pharmacy and so on and liposome performs various functions depending on thefunctional molecules on it [1,2]. Therefore, liposome can be functionalized by synthesizing
chemically-modified DNA on the surface on demand.
This strategy of DNA synthesis is expected to be applied to various fields.
[1] B.Zhao, Q Tian, Y.Bagheri and Mingxu You, Curr. Opin. Biotechnol. 13:76-83 (2020)[2] Philipp M.G. Löffler, Oliver Ries, Alexander Rabe, Anders H. Okholm, Rasmus P.
Thomsen, Jørgen Kjems, Stefa Vogel, Angewandte Chemie, 56-43(2017)

Fig.1. Comparison of DNA synthesis between in bulk and on liposome surface

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Phase stabilities of magnesiated MnO2 polymorphs as cathodes formagnesium rechargeable batteries
Takuya Hatakeyama1, Hongyi Li1, Norihiko L. Okamoto1 and Tetsu Ichitsubo1
1
Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
Magnesium rechargeable batteries that employs magnesium metal anodes are potential
alternatives to currently available lithium-ion batteries. The major advantages of magnesium
metal anodes are derived from its natural abundance, high capacity, and non-dendritic nature.
Abundance of magnesium in earth crust ensures low material cost. Magnesium metal anodeprocesses a high theoretical capacity (2205 mAh/g) that is greater than that of lithium-inserted
graphite (339 mAh/g) and comparable to that of lithium metal (3860 mAh/g). Additionally,magnesium metal tends to be plated uniformly during electrodeposition, thereby ensuring safe
operation, in contrast to Li metal that easily forms hazardous dendrites.
One of huge challenges in developing magnesium rechargeable battery is to establish highcapacity cathode materials. Capacity of 3d-transition-metal-oxide cathodes comes to bestrongly influenced by slow kinetics of magnesium intercalation. To obtain inherent capacity,
the intercalation kinetics must be promoted by reducing the particle size of cathode materials
and elevating cell temperature, etc. Moreover, even if the kinetics is improved, capacity of
most oxide cathodes gradually fades in several cycles of magnesium
intercalation/deintercalation. Such a capacity fade implies irreversible change of cathodematerial caused by magnesium intercalation. Deep understanding of the mechanism ofirreversible process is essential to prevent capacity fade.
The stability of Mg-extracted (i.e., defective) crystal structure is a key factor to enable
reversible magnesiation cycling. According to our previous research, which investigated thepossibility of magnesium deintercalation from spinel family MgTM2O4 (TM= Co, Mn, Fe,Cr), magnesium deintercalation from MgTM2O4 (redox of TM3+/TM4+) can be markedly
observed in the Mn spinel. This result agrees with the fact that Mg-deintercalated structure
Mn2O4 (λ-MnO2) is relatively stable compared to the other transitional metals. In fact, several
stable polymorphic structures known for MnO2, while stable dioxides of Co, Fe, Cr are
difficult to be produced.
In this study, phase stability of magnesium-intercalated polymorphic MnO2 structure( and  has been investigated experimentally and theoretically. The present
electrochemical experiments demonstrate that  and  type structures allow topotacticmagnesium intercalation up to x = 0.16 in MgxMnO2, corresponding to a capacity of 100
mAh/g. X-ray characterization suggests that capacity fade mechanism lies inover-magnesiation that induces transformation from original MnO2 framework into
rocksalt-structured Mg~0.5MnO2. This fundamental understanding of phase stability will
advance further optimization of MnO2-based cathode for magnesium batteries.
[1] T. Hatakeyama, N. L. Okamoto, K. Shimokawa, H. Li, A. Nakao, Y. Uchimoto, H.
Tanimura, T. Kawaguchi and T. Ichitsubo, Phys. Chem. Chem. Phys., 2019, 21,23749–23757.
[2] S. Okamoto, T. Ichitsubo, T. Kawaguchi, Y. Kumagai, F. Oba, S. Yagi, K. Shimokawa, N.
Goto, T. Doi and E. Matsubara, Adv. Sci., 2015, 2, 1500072

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Effect of Minor alloying elements on Microstructural and mechanicalproperties changes in Ti-Fe Alloy
YeonBeom Jeong1* and Hidemi Kato2
1
2

Graduate school of engineering, Tohoku University, 980-8577, Sendai, Japan
Institute for Materials Research, Tohoku University, 980-8577, Sendai, Japan

Generally, eutectic alloys show very high yield strength because of their large number ofinterfaces [1]. However, they offer limited plasticity at room temperature. To improve
plasticity, the development of ultrafine eutectic alloys containing micron-scale dendrites in
the lamellar structure has been highlighted. The primary mechanism for improving theplasticity of these alloys is the rotational motion of the eutectic colony. So, these alloys
effectively diminish the localization of the shear stress, thus improving the plasticity.
Similarly, the formation of chemical heterogeneity in the eutectic alloy increases the ductility
because the formation of different constituent phases in the eutectic colony boundaries
prevents catastrophic failure. In this study, the microstructure alternation and change of
mechanical property are investigated as adding Bi-In eutectic alloy in the Ti65Fe35
hypereutectic alloy. With the addition of Bi-In, the microstructures of (Ti65Fe35)100-x(Bi53In47)x(X= 0, 1, 3, 5, 7) alloys exhibit the dendritic phases having different compositions in the
eutectic matrix. Especially in case of the addition of 3at. % (Bi-In), the TiFe dendritic phasechanges to the β-Ti dendritic phase. This phase deformation leads to implementing theplasticity about four times compared with non-added alloy. To identify the evolution of thedendritic phase's chemical composition, more exactly EDX analysis was conducted. Also, toreveal the reason for enhancing the plasticity fractured surfaced was measured.
[1] Y. B. Jeong et. al. Mater. Des. 175 107814 (2019)

Fig. 1. Influence of (BiIn) on TiFe fine eutectic alloy

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Revealing the Reaction Mechanism of Li-O2 Battery
by in-situ Surface-Enhanced Raman Scattering (SERS)
Koki KANNARI, Aimin GE, Ken-ichi INOUE and Shen YE
Department of Chemistry, Graduate School of Science, Tohoku University
Lithium-Oxygen battery (Li-O2 battery) has attracted much research attention due to its hightheoretical specific energy density, which is much higher than that of practical lithium-ion
batteries [1]. Therefore, Li-O2 battery is expected as one of the next-generation secondary
batteries for electric vehicle’s power source.
The main electrode reactions of Li-O2 battery are shown in below. On the cathode surface,oxygen reduction reaction (ORR) occurs during the discharging process, and oxygen evolution
reaction (OER) proceeds in the charging process.
(1)
Anode :
Li ⇄ Li+ + e+
Cathode :O2 + 2Li + 2e ⇄ Li2O2(2)
Li-O2 battery is promising but still has many problems. Especially, high charge overpotential on the cathode, which causes electrolyte decomposition, becomes a bottleneck in LiO2 battery development. However, the origin of the problem is still unclear because
understanding the reaction mechanism on the cathode surface is not enough. In the present
study, surface-enhanced Raman scattering (SERS) has been employed to investigate the
ORR/OER on a cathode surface made of nanostructured gold materials. SERS measurement
enables us to selectively observe the species on the surface during the electrode reactions [2].
Combining SERS technique with cyclic voltammetry measurements, the reaction mechanisms
of ORR / OER process on the cathode surface were investigated in situ to make a strategy tounderstand the origin for the high charge over-potential.
The in-situ SERS measurements show that the lithium peroxide (Li2O2) is formed on thecathode as the cathodic currents flows in the discharge process. The SERS signals for the Li2O2
quickly disappear as soon as the anodic current starts to flow, although the anodic current stillflows until the potential becomes higher than 4.0 V (vs. Li+/Li). Based on the observation, it isreasonable to conclude that Li2O2 is initially decomposed from the interface between Li2O2 andthe cathode surface (Figure 1). A higher charge over-potential is required to decompose Li2O2
remaining away from the electrode surface. Detailed discussions will be given during thepresentation.

Fig. 1. Schematics of the reaction mechanism for OER during charging process[1] D. Aurbach, B.D. McCloskey, L.F. Nazar, and P.G. Bruce Nat. Energy, 2016, 1, 16128[2] X.-B. Han, K. Kannari, S. Ye Curr. Opin. Electrochem., 2019, 17, 174

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High-Pressure Synthesis and Defect Chemistry of Hydrated Ba-Sc-Based
Perovskites
Hiroaki Kawamori1, Itaru Oikawa1 and Hitoshi Takamura1
1

Department of Materials Science, Tohoku University,
hiroaki.kawamori.s2@dc.tohoku.ac.jp

Hydrogen energy has been highly demanded for sustainable society. Hydrogen generation,
storage, transportation, and conversion to electricity are keys for its practical application.
Proton (H+)-conducting solid-oxide fuel cells have high energy conversion efficiency. Manyefforts have been made to develop proton-conducting electrolytes. Acceptor-doped
perovskite-type oxides (ABO3) are expected as the electrolyte because of their high proton
conductivity. Acceptor-ions are charge compensated by oxygen vacancies and protons
depending on atmosphere, especially relative water vapor pressure. Increase in the proton
concentration is demanded to achieve high conductivity.
In this study, Ba-Sc-oxide was focused on. It has oxygen-deficient perovskite structure
under conventional synthesis condition. Although it has large amount of oxygen vacancies forhydration reaction, the reports of hydrated Ba-Sc-oxide are limited [1]. Now, we synthesized
hydrated Ba-Sc-oxide by using high-pressure method and investigated its structure,composition and proton concentration.
Ba(OH)2·H2O and Sc2O3 are heated up to 1200°C under 8 GPa within Au sealant. The
obtained sample had orthorhombic perovskite-type structure with the ratio Ba:Sc of 3:2. Thisimplies that a large amount of Sc vacancies are formed on B sites. The weight change by
dehydration that indicates its proton concentration is shown in Fig. 1. The large weight loss
can be hardly discussed without taking Sc vacancies into account. It showed good agreementwith the amount of protons that are required for compensation of Sc vacancies. The B-cation
deficient hydrous perovskite was also obtained from hydrogarnet-type Ba3Sc2(OH)12 whosevacant cation sites are known to be compensated by protons. Their structural relationship isshown in Fig. 2. The compensation mechanism of Sc vacancies in perovskite structure seems
to resemble that of vacant cation site in hydrogarnets.
A2B2O5Oxygen-deficient perovskite+H2O
High temp.
High press.

A3B2(OH)12
Hydrogarnet-H2O

B-cation deficienthydrous perovskite

Fig. 2 Weight change of Ba-Sc
based B-cation deficient hydrous
perovskite by dehydration.

Fig. 2 Crystal structures of B-cation deficienthydrous perovskite and related compounds.

[1] Rinlee B. Cervera, Shogo Miyoshi, Yukiko Oyama, Youssef E. Elammari, Takehiko Yagi,
and Shu Yamaguchi, Chem. Mater. 25, 1483–1489 (2013).

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Mixed Conduction and Local Structural Analysis of
Y and Al co-doped BaZrO3
Koya Kimura1*, Itaru Oikawa1 and Hitoshi Takamura1
1

Department of Metallurgy, Materials Science and Materials Processing, Tohoku University

Mixed proton-hole conductor is expected to be a cathode material for proton conducting
solid oxide fuel cells (PCFCs). Accepter-doped BaZrO3 has oxygen vacancies that can beeither proton defects in wet condition or holes in oxydizing condition. Mixed proton-hole
conduction is achieved when both proton and hole concentration are high. Takahashi et al.
investigated the relationship between local structural distortion and hydration energy ofaccepter-doped BaZrO3[1]. It was suggested that large Y3+ prefers the compensation by
proton defects; on the other hand, small Al3+ does holes or oxygen vacancies. Thus, by doping
Y and Al into BaZrO3, we expect to achieve mixed proton-hole conduction. In this study, thelocal structure around dopants, especially around Al, is focused on. Nuclear magnetic
resonance (NMR) spectroscopy is a powerful tool to investigate the local structure aroundnuclei. We can evaluate the coordination number of oxygen around Al, and it can beconverted to the amount of oxygen vacancies. We therefore evaluated the defect equilibriumof Y and Al co-doped BaZrO3 from the view point of local structure, and its mixed
conductivity.
BaZr0.8Y0.2-xAlxO3-δ (BZYA) was prepared by solid state reaction method. Proton
concentration was evaluated by thermogravimetric analysis at 350ºC. AC impedance
measurement was performed to evaluate the conductivity of BAYA in dry Ar or wet Ar.
Proton transport number was measured at 600ºC by using water vapor concentration cell. 27Al
Magic-Angle Spinning (MAS) NMR was performed to investigate the configuration around
Al. Proton concentration of BZY10A10, BZY15A5 was 0.6 mol%, 1.8 mol% (Fig. 1). They
were much smaller than that of BZY20, 18.6 mol%. This indicates that Al substitution led todecrease in proton concentration. Meanwhile, BZYA showed proton conduction and highproton transport number, 0.84. This is due to the unique oxygen configuration around Al. In
this poster session, we discuss the local structure around Al from NMR spectra (Fig. 2) and its
effect on proton concentration and mixed conduction.

BZY15A5BZY10A10
BZY15A5
150

100

50

0

-50

Chemical Shift (ppm)Fig. 2 27Al MAS NMR spectra of
BZYA

Fig. 1 Proton concentration of
BZYA at 350ºC[1] H. Takahashi et al., Chem. Mater. 29, (2017) 1518.

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Effect of Anodizing Time on Galvanic Corrosion Resistance on
Localized Corrosion Initiated at IMP of Al Alloys
Takumi Kosaba1*, Izumi Muto1 and Yu Sugawara1
1

Department of Materials Science, Tohoku University

As global warming become serious problems, the demand for weight reduction of
automobiles is increasing these days: then the multimaterial structures, which is one of themethods to achieve the weight reduction, attract great interest. Because of low cost and highstiffness, Al alloys and steels joints are especially anticipated to utilize in the structures.
However, galvanic corrosion is expected to occur on anode (less noble potential metals) suchas Al alloys when dissimilar metals are contacted.
In our previous research, the effect of anodizing on galvanic corrosion resistance of pure Al
coupled to pure Fe or Type 430 stainless steel was studied, and it was obtained that more than
400 nm thickness of anodic oxide film is needed to prevent galvanic corrosion damage of pure
Al coupled to pure iron. It was expected that thicker anodic oxide film was needed to enhancegalvanic corrosion resistance for Al alloys because Al alloys has lower corrosion resistancethan pure Al due to existence of intermetallic particles. The intermetallic particles containing
Fe or Cu increase the mechanical strength of Al alloys. In contrast, the boundary between Al
matrix and the particles is likely to become initiation sites of localized corrosion on Al alloys
because electrode potential of the particles is higher than that of Al matrix. Consequently, it isneeded to control the anodic oxide film on Al matrix and intermetallic particles to prevent
galvanic corrosion of Al alloys.
In this study, we investigated the effect of anodizing time on galvanic corrosion resistanceof Al alloys coupled to pure Fe or Type 430 stainless steel in diluted synthetic seawater. This
electrolyte is suitable for simulating the corrosion behavior in atmospheric environments.
AA5083 (Al alloy containing Mg) was used as the specimens. In this alloy, Al6(Fe, Mn) and
Mg2Si particles were contained as intermetallic particles. The galvanic corrosion tests werecarried out by zero resistance ammeter techniques. Anodizing was performed in sulfuric acidin applied voltage of 16 V for 18 to 180 s. The relationship between galvanic corrosion
resistance of A5083 and the thickness of anodic oxide films was determined.

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Giant Vesicle of AOT:New Material for Soft Microscale Compartment and its Dynamic Property
Minoru Kurisu1*, Ryosuke Katayama1, Yuya Takashima1, Peter Walde2 and Masayuki Imai1
1

Department of Physics, Tohoku University
2
Department of Materials, ETH Zürich

Microscale vesicles composed of amphiphilic molecules have attracted muchinterdisciplinary interests as promising soft materials especially in the field of molecularrobotics, microreactor and artificial cell research. Here we report the promising properties of
AOT giant vesicles for these research fields in comparison with conventional vesicles
composed of phospholipid and fatty acid. In aqueous solution, amphiphilic molecules such as
phospholipid and fatty acid are known to form vesicle (cell membrane-like closed sphericalmembrane) spontaneously. These vesicles can separate aqueous solution into two regions bymembrane: small volume of solution inside the membranes and large volume of bulk solution
outside the membranes. Therefore, vesicles have attracted much interests in the fields ofmicroscale chemistry and engineering. For example, one can realize localized chemical
reaction inside vesicle. Another example is molecular robot that load functional molecules
such as protein, enzyme and molecular motor on vesicles. For those applications of vesicles,
the physical and chemical properties of vesicles such as membrane elasticity, permeability
and stability deriving from membrane-forming molecules are necessary. AOT, i.e., sodiumbis-(2-ethylhexyl) sulfosuccinate, is amphiphilic molecule, and we invented fabrication
method of 10-20 µm size giant vesicles of AOT. Critical vesicle concentration of AOT isdependent on temperature and concentration of sodium ion, and utilizing these properties, it ispossible to fabricate AOT giant vesicle with simpler way than gentle hydration method. In
addition, giant vesicle of AOT might have large potential for application that requires
membrane deformation. In comparison with widely used phospholipid giant vesicle, AOT
membrane is thinner and rougher in molecular scale [1], which enables higher permeability
and following osmotic swelling (Fig.1). Furthermore, coupled with a vesicle membranesurface-confined polymerization reaction, AOT based giant vesicles show growth/division
cycles as we previously reported (Fig.2) [2]. In this poster, we show how to fabricate giant
vesicle of AOT and the recent results of a series of investigations on physical and chemical
properties of AOT membrane. Our investigations imply that AOT giant vesicles have higher
transmembrane permeability even for relatively large molecules such as glucose, andconcerning the deformation properties, AOT vesicles might be promising soft materials formolecular robot and artificial cell.
[1] K. Junker et. al., ACS Catalysis, 4, 10 (2014)[2] M. Kurisu et. al., Communications Chemistry, 2, 117 (2019).

Fig. 1. Swelling of AOT vesicles caused byuptake of water.

Fig. 2. Division of AOT base giant vesicles.

142

P-65

Synthesis and n-type thermoelectric application of pyranylidene-substituted
heteroaromatics with extremely high electron-donating ability
Takaya Matsuo1, Kohsuke Kawabata1,2 and Kazuo Takimiya1,21Department of Chemistry, Graduate School of Science, Tohoku University
2
RIKEN Center for Emergent Matter Science

Thermoelectric conversion is a technology that can convert unused thermal energy toelectric power. Although inorganic thermoelectric materials exhibit high device performanceand robustness, organic counterparts offer advantages such as low cost, large-area deposition,high elasticity, material abundance, and low weight.
In thermoelectric device, doping is a key process to optimize the thermoelectric conversion
efficiency. In the prototypical n-type dopants (e.g. N-DMBI), a doping process is composedof the initial thermal cleavage of C-H bond to produce a radical species, which then donates
electron from its SOMO (Fig. 1a) [1]. However, the radical species may react with hostmaterials undesirably. On the other hand, electron donation from HOMO of closed-shellmolecules dose not accompany such undesired reactions. However, it is challenging to realize
a compound with HOMO energy levels higher than the LUMO energy levels of commonlyused n-type organic semiconductors. Therefore, a design strategy for increasing the HOMO
energy levels is a key to develop superior dopants to improve thermoelectric properties.
In this context, pyranylidene-substituted heteroaromatics, which have been previously
reported to have high-lying HOMO energy levels, is a promising platform for n-type dopants[2]. In this study, to further improve electron-donating ability, we introduced
electron-donating groups, namely, methoxy and dimethylamino groups, on the pyranylidene
rings, and thus developed 1a, 1b, 2a and 2b (Fig. 1b) are examined as n-type dopants on
N2200, which is one of representative host materials in n-type organic thermoelectric devices.
The HOMO energy levels of 1a-2b calculated by DFT methods are approximately 3.7 eV
below the vacuum level, which suggests that the compounds have extremely highelectron-donating ability. Upon doping with 1a-2b, the electrical conductivity of doped
N2200s were increased, and the Seebeck-coefficient measurement confirmed that they show
n-type thermoelectric performance. In this presentation we also report the power factors of
doped N-2200 depending on the dopants (1a-2b, and N-DMBI) and their concentration.
[1] P. Wei, J. H. Oh, G. Dong, and Z. Bao, J. Am. Chem. Soc. 132, 8852 (2010).
[2] K. Takimiya, T. Otsubo, F. Ogura, H. Ashitaka, K, Morita, and T. Suehiro, Chem. Lett.
23, 255 (1994).

Fig. 1. Doping processes of (a) N-DMBI and (b) n-type dopants in this study

143

Anomalous magnetoresistance of antiferromagnetic
semiconductor BaMn2Bi2
Takuma Ogasawara1*, Kim-Khuong Huynh2 and Katsumi Tanigaki3
1

2

Dept. of Phys., Grad. School of Sci., Tohoku Univ.*, Miyagi, Japan
WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku Univ., Miyagi, Japan3
Beijing Academy of Quantum Information Sciences (BAQIS), Beijing, China

Recently, the antiferromagnetic (AFM) materials have been studied intensly due to thepotential for spintronics material as well as physical viewpoint because AFM device resolve
the vulnerability issue of the conventional spintronics memory device consisted offerromagnet against strong magnetic field and stray field. Simultaneosly, such a robustness
makes it difficult to manipulate and read the magnetic ordering of AFM. Although somesuccessful studies reported that the AFM ordering was manipulated via inverse spin galvanic
effect and read by anisotropic magnetoresistance [1,2], they are still far from application due
to the fewness of candidate materials due to the requirement of extraordinal symmetry, odd
for both space inversion and time reversal operation, and requirement for highcurrent-density. Further research for sphisticated physical phenomena in antiferromagnetic
materials is needed for more progress.
In this poster, we present the anomalous magnetoresistance in the antiferromagnetic
material BaMn2Pn2 (Pn: As, Sb, Bi) [4] that is cllasified to specific magnetic point group, thatis odd for both space inversion and time reversal operation similar to antiferromagnetic
materials refered in [1,2], predicted to drive some intriguing physical phenomena such as
inverse spin galvanic effect [3]. Their magnetoresistance become significant, whose signchanges depending on temperature and strength of magnetic field, when the magnetic field
applid perpendicular to AFM ordering [5]. Although the relationship between thismagnetoresistance and theoretical analysis of symmetry is unclear, no siguniture of phasetransition in other physical properties i.e. heat capacity and magnetization under strong
magnetic field suggests that magnetoresistance in BaMn2Pn2 is not caused by conventional
magnetic field induecd phase transition such as spin-flop transition.
In the session, I show the details of these data and discussed some possibilities ofmagnetoresistance.
[1] P. Wadley, B. Howells, J. Železný et al., Science 351, 587 (2016).
[2] S. Y. Bodnar, Šmejkal et al., Nature Communications 9, 348 (2018).
[3] H. Watanabe and Y. Yanase, Phys. Rev. B 96, 064432 (2017).
[4] K.-K. Huynh, T. Ogasawara et al., Phys. Rev. B 99, 195111 (2019).
[5] T. Ogasawara, K.-K. Huynh et al., ArXiv:2010.00807 [Cond-Mat] (2020).

P-67

Effect of the Alkyl Linker of Thiazole Orange Base Surrogate in the Peptide
Nucleic Acid-DPQ Conjugate on the Binding and Fluorescence Sensing of
the Promoter Region of Influenza A Virus RNA
Okeke Chioma Uche, Hiromasa Miura, Yusuke Sato, Seiichi Nishizawa* Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan
New class of drug candidates targeting the influenza A virus (IAV) has been highly
desirable considering the emergence of drug resistant IAV strains. In this context, muchattention has been paid to RNA-binding molecules for the promoter region of IAV RNA as
this region is not involved in the genetic variations associated with pathogenesis and antiviralresistance. In an early attempt, aminoglycosides antibiotics were shown to work as usefulbinders. However, given some inherent problems such as promiscuous binding to various
RNA structures and the risk of adverse effects, their clinical use would be severely limited.
We recently developed the conjugate of triplex-forming peptide nucleic acid (TFP) carrying
thiazole orange (TO) base surrogate with small molecule (DPQ) as the promising candidates
for the promoter region. Here, TFP unit can recognize the double-stranded structure.
Meanwhile, DPQ unit can bind selectively to the internal loop of the promoter region. The
binding of the conjugate can be monitored by the light-up response of TO base surrogate thatis connected with the peptide nucleic acid (PNA) backbone through an acetyl linker. This
conjugate was demonstrated to strongly and selectively bind to the IAV RNA promoter
region.
In this work, we examine the effect of TO base surrogate on the binding and fluorescencefunctions of the conjugate for IAV RNA promoter region. Based on our previous findings, we
explored the use of a propyl linker in the conjugate. TO base surrogate in the conjugate wasalmost non-fluorescent, but its fluorescence was greatly enhanced upon binding to the model
RNA containing the promoter region, although the light-up response is moderate compared tothe acetyl-linker containing conjugate that was previously developed by us. This can be
explained by the intercalation of the TO unit into the triplex structure that can be formed
between the target RNA and the TFP unit of the conjugate. However, we found that the
conjugate carrying the propyl linker showed the enhanced binding affinity for target RNAcompared to the acetyl linker-containing one. These results indicate the favorable effect of the
propyl linker on the binding affinity of the conjugate for the IAV RNA promoter region.
Further details of the present conjugates will be discussed in the presentation.
[1] T. Sato, Y. Sato, and S. Nishizawa, J. Am. Chem. Soc. 138, 9397-9400 (2016).
[2] M.-K. Lee, A. Bottini, M. Kim, M. F. Bardaro Jr., Z. Zhang, M. Pellecchia, B.-S. Choi,and G. Varani, Chem. Commun. 50, 368-370 (2014).
[3] T. Sato, Y. Sato, and S. Nishizawa, Chem. Eur. J. 23, 4079-4088 (2017).

145

P-68

Fabrication of Type 304L Stainless Steel Containing Mo-rich Phases By
Spark Plasma Sintering and Its Corrosion Resistance in 0.1 M NaCl
Haruka Saito 1*, Izumi Muto 1 and Yu Sugawara 1
1

Department of Materials Science, Tohoku University, 6-6-02, Aza-Aoba, Aramaki,
Aoba-ku, Sendai 980-8579, Japan

It is well known that the corrosion resistance of stainless steels is improved by addition ofMo [1]. The role of Mo has been investigated for long time. It was proposed that Mo forms
Mo-oxides and inhibits corrosion attack [2]. In addition, it is suggested that Mo changes the
structure of the Cr oxide layers on stainless steels [3].
In this study, we fabricated type 304L containing Mo-rich phases by Spark Plasma
Sintering (SPS), and the corrosion resistance was assessed in 0.1 M NaCl.
Type 304L containing Mo-rich phases was fabricated by SPS. As the starting materials,
pure Mo powders and type 304L stainless steel powders were used. Table 1 shows thechemical composition of type 304L powders. Sintering was performed at 1373 K for 20 min.
After sintering, the specimen was heat-treated at 1573 K for 5 h and quenched in water. After
that, the solution treatment (1373 K, 30 min) was conducted and water quenched. The
specimen surface was polished down to 1 μm using a diamond paste. Sintered type 304L andtype 316L were used as reference materials. The same SPS procedure and solution treatment(1373 K, 30 min) were applied to prepare those.
The surface of type 304L containing Mo-rich phases was inspected using an optical
microscope. specimens were also analyzed using a scanning electron microscope (SEM)
equipped with an electron probe micro analyzer (EPMA).
Potentiodynamic polarization was conducted in 0.1 M NaCl. Specimens were covered by
epoxy resin, with the exception of the electrode area (5 mm × 5 mm).
On the basis of the surface observations, it was suggested that the steel matrix of type 304L
containing Mo-rich phases is austenite, but many voids were generated. Mo-rich phase wereobserved on the entire surface.
In polarization measurements, the passive current density of type 304L containing Mo-richphases and type 316L was unstable, because of the presence of voids. However, the pitting
potentials of type 304L containing Mo-rich phases were higher than those of type 316L. The
existence of Mo-rich phases inhibited pitting growth.
[1] M. Nishimoto, I. Muto, Y. Sugawara, and N. Hara, J.Electrochem.Soc., 166(11) (2019),
C3081-C3089.
[2] K. Hashimoto, K. Asami, and K. Teramoto, Corros. Sci., 19 (1979), 3-14.
[3] M. F. Montemor, A. M. P. Simões, M. G. S. Ferreira, M.D.C. Belo, Corros. Sci., 41(1999), 17-34.
C
0.01

Table 1 Chemical composition of type 304L gas atomized powders (mass%)
Si
Mn
P
S
Ni
Cr
Mo
Cu
Ti
Al
Nb
0.22 0.17 0.012 0.0025 11.13 19.01 0.01 0.01 0.001 0.002 0.007

146

P-69

Elucidation of the Initiation of Pitting Corrosion and the Growth of Filiform
Corrosion of AZ91D Die-cast Mg Alloy
Shao Zheng1 *, Muto Izumi1, Sugawara Yu2
Tohoku University Graduate School of Engineering,6-6, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi

1980-8579, Japan
2

Tohoku University Graduate School of Engineering,6-6, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi
980-8579, Japan

1 Introduction
Mg-Al-Zn alloys such as AZ91 (Mg-9% Al-1% Zn) are very lightweight, and expected to be
used in transportation equipment (e.g.: automotive and aerospace). Mathieu et al. studied the effectof elements and phase compositions of AZ91 alloy on corrosion behavior 1)-2), and they revealed
that the content of aluminum and the distribution of Mg17Al12 have the significant effect on the
corrosion resistance of the alloy. However, the corrosion mechanism is still not perfectly figuredout. In this study, the aim is to elucidate the initiation of localized corrosion of die-cast AZ91D.
2 Experimental
2.1 Macro-scale electrochemical measurements
Open circuit potentials and potentiodynamic polarization curves were measured at 298 K. The
specimen surfaces were coated with an epoxy resin and subsequently with paraffin. Measurements
were performed in a conventional three-electrode cell: the counter electrode was a Pt wire, and thereference electrode was Ag/AgCl (3.33 M KCl). The electrolyte used were naturally aerated 0.1 M
and 0.01M NaCl (pH 8.0, adjusted with NaOH). The size of the electrode area was ca. 1cm2.
2.2 Micro-scale electrochemical measurements
To elucidate the pit initiation sites, potentiodynamic polarization curves for a small electrodearea for AZ91D die-cast were measured. The electrode area was ca. 0.25 mm2 or ca. 0.01 mm2.
The specimen surfaces, with the exception of the electrode area, were masked with a silicone
sealant, and the sealant was dried for 24 h. To preserve the electrolyte, a small acrylic cell was puton the specimen. Before the potentiodynamic polarization, the reference and counter electrodes
were connected with a small droplet of the electrolyte. The electrolyte used were naturally aerated
0.1 M NaCl (pH 5.46) and 0.01M NaCl (pH 8.0, adjusted with NaOH). After polarization, corrosion
morphology was characterized using a laser microscope, optical microscope, and FE-SEM.
3 Conclusion
In macro-scale measurements, the open circuit potential was approximately -1.5 V but
oscillating during the immersion. The oscillations were due to the competition of corrosion
initiation and repassivation. After immersion, it was observed that filiform corrosion occurred.
In micro-scale polarization, regardless of the size of the sample area, pitting tended to occur
underneath the coating. The discoloration occurred on the eutectics. Some eutectics discolored, andsome did not transform. The discolored eutectics might be close to the grain boundaries. The
initiation of pitting was seen at the eutectic phase adjacent of β phase. Pitting caused the initiationof filiform corrosion. After the pit initiation, hydrogen gas bubbles were generated. During the
growth of filiform corrosion, hydrogen was also continuously produced.
[1] S. Mathieu, C. Rapin, J. Steinmetz, and P. Steinmetz, Corros. Sci. 45, 27412755(2003)[2] Y. Li, T. Zhang, F. Wang, Electro Acta, 51, 28452850(2006)

147

P-70

Oxidation Mechanism of the Unsaturated Phospholipid Monolayer
in the Low-level Ozone Studied by HD-SFG
Chunji TAKADA, Ken-ichi INOUE, Aimin GE and Shen YE
Department of Chemistry, Graduate School of Science, Tohoku University, Japan
Pulmonary surfactant is known to reduce the surface tension at air-water interface of thealveoli. Both saturated and unsaturated phospholipids are included in the pulmonary surfactant
and play essential roles in lung function. Ozone is one of the most oxidative compounds andexists in ambient air at a low-level (20~40 ppb). During respiration, ozone reaches the alveoli
and reacts with pulmonary surfactant. In our previous study, it was found that the unsaturated
alkyl chain of phospholipids was selectively oxidized in the low level ozone by using
conventional sum frequency generation (SFG) spectroscopy and Langumuir monolayer
technique. SFG spectroscopy (Fig. 1) provides information of molecular structure on theinterface at molecular level while Langmuir monolayer technique does macroscopic
information of the monolayer by measuring π-A isotherms (surface pressure-area permolecule).[1,2] However, the results could not give enough information to identify the oxidized
compounds and their amount. This is because conventional
SFG can only provide thesquare of��
the second-order nonlinear susceptibility, �𝜒𝜒 (�) � information. Since �𝜒𝜒 (�) � is heavily
distorted due to the interference among the resonant peaks, the accurate interpretation is very
difficult. In the present study, heterodyne-detected sum frequency generation spectroscopy(HD-SFG) was used to measure the imaginary part of 𝜒𝜒 (�) which directly reflects thevibrational resonance and can be interpreted more straightforwardly. In situ HD-SFG study
revealed that the unsaturated phospholipid, 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine(POPC) was rapidly decomposed by the low-level (20~40ppb) ozone and the oxidized
compounds from POPC were mostly consist of 1-palmitoyl-2-(9'-oxononanoyl)-sn-glycero-3phosphocholine (POnPC), in which the C=C bond in an unsaturated alkyl chain of POPC iscleaved and replaced by aldehyde[3]. The mixed monolayer’s structure of POPC and a major
saturated lipid of pulmonary surfactant (1,2-dipalmitoyl-sn-glycero-3-phosphatidyl-choline(DPPC)), which is a better mimic of alveoli’s surface, was also examined. The detailed results
will be discussed in the poster.

[1]L.Qiao, A.Ge, M.Osawa, and S.Ye, Phys. Chem. Chem. Phys. 2013, 15, 17775 .
[2]L.Qiao, A.Ge, Y.Liang, and S.Ye, J. Phys. Chem. B, 2015, 119, 14188 .
[3] K.Inoue, C.Takada, L.Wan, A.Morita and S.Ye, J. Phys. Chem. B, 124, 5246 (2020)

148

P-71

Surface oxygen dissociation reaction rates of Co-containing oxides
Toma Tazawa1*, Yuto Tomura1, Itaru Oikawa1 and Hitoshi Takamura1
1

Department of Materials Science, Graduate school of Engineering, Tohoku University*
Sendai 980-8579, Japan*Email: tazawa@ceram.material.tohoku.ac.jp

While solid oxide fuel cell (SOFC) shows the highest efficiency among fuel cells, there is aserious problem that operating temperature is as high as 750 °C. Oxygen surface exchange
reaction, which takes place on cathode surface, is a rate-determining step and prevents SOFC
from reducing its operating temperature. It is therefore necessary to develop oxides showing
high exchange reaction rates and to understand the reaction mechanism. Co-containing oxides
such as BSCF and LSC are well-known oxides with high exchange reaction rates. However,
the roles of Co on the surface exchange reaction have not been understood yet. In this study,
we prepared Co-doped MgO, which has low defects concentration, and investigate the effectsof Co content on oxygen surface exchange reaction, especially dissociation reaction rates. In
addition, Ni-doped MgO, which is also a 3d transition metal oxide, was examined.
Co- and Ni-doped MgO were fabricated by the Pechini method and confirmed to be a single
phase and cubic rock salt-type structure. A modified pulsed isotopic exchange (PIE) was used
to quantitatively evaluate their oxygen surface exchange reaction and dissociation reaction
rates [1]. No incorporation of oxygen into Co-doped MgO was observed because of very
limited oxygen vacancy due to the donor-type defects, Co3+, on surface. As shown in Fig. 1,
dissociation rate increased with increasing concentration of the Co ion. Meanwhile, decreasein activation energy with increasing Co content was confirmed. For Ni-doped MgO, increasein the catalytic activity was observed only in a range of higher concentration of Ni. These
trends suggest that not only cations act as activation site on surface, but also their electronic
structure strongly affects the catalytic activity.

NiO

Ni80

Co50

Co10
MgO

Co20

Ni50

Co40

Ni20

Fig. 1 Arrhenius-type plot of oxygen surface dissociation rates of Co- and Ni-doped MgO[1] Y. Tomura, T. Tazawa, I. Oikawa and H. Takamura, J. Mater. Chem. A, in press.

149

P-72

Local structure and mixed conductivity of Co-doped BaZr0.9Sc0.1O3-δ
Hiroki Uehara *, Itaru Oikawa, Hitoshi Takamur
Department of Materials Science, Graduate School of Engineering, Tohoku University,
Sendai 980-8579, Japan, uhiroki@ceram.material.tohoku.ac.jp
Proton-conducting solid oxide fuel cell (pc-SOFC) is expected to be one of the mostefficient, highly stable, and cost-effective SOFCs. As a cathode material for the pc-SOFC, acomposite cathode system comprising of both electron- and proton-conducting materials has
been examined and developed. In such case, the reaction area is limited to the triple phaseboundary, and resultant cathode performance is poor. On the other hand, for a mixed
proton-hole conductor (MphC), the reaction area will be expanded to the whole surface of
cathode; the efficiency of the cell will be significantly enhanced[1]. However, almost nopractical MphC material has been developed because the effect of the proton-hole correlationon the carrier conductivity is unclear. In this study, we investigate the effect of proton-holecorrelation on mixed conduction from a local structural viewpoint.
To fabricate proton-hole mixed conductor for a pc-SOFC cathode, two kinds of metal were
doped to BaZrO3. One is cobalt with valence state +3, which create holes, and the other islanthanide, Sc, around which protonic defects can be formed [2-4]. BaCoxZr0.9-xSc0.1O3-δ (x =0, 0.01, 0.04, 0.1, 0.2) was prepared by solid-state reaction. All the samples were confirmed to
be a single phase and cubic perovskite structure. Thermogravimetric analysis was carried out
under dry/wet N2 to calculate the amount of proton in the sample. Co-doped samples showed
lower proton content than that of a sample without Cobalt. The main carrier was suggested tobe hole based on EMF and PO2 dependence of total conductivity. The conductivity of x = 0.04
sample under wet Ar was higher than the conductivity under dry Ar whereas the conductivity
measured under dry oxidizing atmospheres was higher than that under wet atmospheres. Thisimplies that the conductivity is decreased by proton introduction when the hole concentration
is high. 1H and 45Sc magic angle spinning (MAS) nuclear magnetic resonance (NMR)
spectroscopy were carried out for x = 0.01 and 0.04 samples annealed under wet Ar/O2 orvacuum condition. It was suggested that proton was incorporated in all of the samples
annealed under wet atmospheres. Comparing the 45Sc MAS NMR spectra of samples annealed
under wet Ar and O2, it was implied that the proton amount in the sample decreases whenhole concentration of sample increases (PO2 of heat-treatment condition increases), in spite ofconstant Sc concentration ([Sc] = 0.1). In summary, it is suggested that proton-holecorrelation appears to have a negative effect on both hole and proton conduction. In order todecrease the correlation, separation of proton/hole conducting path is important fordevelopment of practical proton-hole mixed conducting materials for pc-SOFC cathode.
[1] E. Fabbri, A. Magrasó, and D. Pergolesi, MRS Bull. 39, 792 (2014).
[2] V.P. Gorelov, V.B. Balakireva, Y.N. Kleshchev, V.P. Brusentsov, Inorg. Mater. 37 (2001)
535-538.
[3] I. Oikawa and H. Takamura, Chem. Mater. 27 (2015) 6660-6667.
[4] Y. Rao, S. Zhong, F. He, Z. Wang, R. Peng, Y. Lu, Int. J. Hydrog. Energy 37 (2012)12522-12527.

150

P-73

Black Titanium Oxynitride Thin Films Prepared by Ion-Beam-Assisted
Pulsed Laser Deposition
Mina Yamaguchi, Akihiro Ishii, Itaru Oikawa, Hitoshi Takamura
Department of Materials Science, Graduate School of Engineering, Tohoku University,
Sendai, Japan, mina.yamaguchi.q1@dc.tohoku.ac.jp

10080

W-doped Ti(O,N)x

Ti(O,N)x

W-doped Ti(O,N)

60
40

DOS

Absorption coefficient,, α /µm-1Preference for a classy black turn-off appearance and for distinct dark colors on flat-panel
displays has led to a high demand for optically black materials. The black materials are required
to have a large optical density (i.e. high magnitude of absorbance), have absorption which isless wavelength-dependent in the visible range (λ = 400–700 nm), and also be homogeneous at
the micro scale to avoid light scattering. It is difficult to satisfy these three requirements
simultaneously. In this study, we focused on the Ti-O-N materials since the flat and constantabsorption in visible range can be expected due to coexisting of both of interband absorption(cf. nitrogen doping in TiO2) and free-carrier absorption (cf. TiN).
Titanium oxynitrides and tungsten-doped oxynitrides were prepared using nitrogen plasma
assisted pulsed laser deposition, and their optical absorption properties were investigated. A
selection of Ti-O-N films were prepared with different compositions by controlling theemission current (Ie) and discharge voltage (Vd) of the ion source. It was found that the nitrogencontent of the Ti(O,N)x could be adjusted by controlling the Ie. The large, flat absorption
coefficient of approximately 40 μm−1 in the visible range (400–700 nm) attained for the samples
deposited at high Vd (300 V) was attributed to tungsten doping from a W filament in the ion
source. The 4.1 mol%W-doped Ti(O,N)x, which had a rock-salt-type structure, was optically
jet-black. The origin of the flat wavelength dispersion in the W-doped Ti(O,N)x was attributed
to the coexistence of semiconducting absorption and metallic absorption mechanisms. DFT
calculations suggest that the 5d states achieved when using doped tungsten provide highabsorption in the mid-wavelength range, whereas undoped- Ti(O,N)x was characterized byweak absorption.

20
0
400

500

600

Ti 3d
O 2p N 2p

700

Energy, E

Wavelength, λ /nm
Fig. 1. Absorption coefficient of the undoped and tungsten doped titanium oxynitride
thin films and the appearances[1] M. Yamaguchi, A. Ishii, I. Oikawa and H. Takamura Applied Surface Science. 534, 147616(2020).

151

W 5d

P-74

Synthesis of anti-ThCr2Si2-type La2O2Bi epitaxial thin film by multilayer
solid-phase epitaxy method
Yuki Yamamoto1, Hideyuki Kawasoko1 and Tomoteru Fukumura1,2
1

2

Department of Chemistry, Graduate School of Science, Tohoku University
WPI-Advanced Institute for Materials Research (WPI-AIMR) and Core Research Cluster,
Tohoku University

c-axis length (Å)[1] H. Mizoguchi et al., J. Am. Chem. Soc. 133, 2394 (2011).
[2] K. Matsumoto et al., Appl. Phys. Lett. 116, 191901 (2020).

152

FWHM of 006 RC (deg)Anti-ThCr2Si2-type RE2O2Bi (RE = rare earth)** substratecomposed of Bi square nets and RE2O2 layers
750 ºC
shows metal-insulator transition by substituting RE
elements, and La2O2Bi is an insulator [1]. Recently,
La2O2Bi bulk polycrystals have demonstrated
metallic conduction with high hole mobility by*
expanding c-axis length via excess oxygen*
850ºC
intercalation [2]. Accordingly, highly crystalline
La2O2Bi is intriguing for the further development of
the transport properties. In this study, we
synthesized La2O2Bi epitaxial thin films by
multilayer solid-phase epitaxy method.
Multilayer precursors were deposited on*
MgO(001) substrate at room temperature by
950 ºC*
magnetron sputtering in Ar gas atmosphere. The
structure of multilayer precursors was [Bi (3.0 nm)/ La (7.2 nm)]10 (nominal composition: La2.0Bi1.0)
with Si3N4 capping layer (4 nm). Subsequently, themultilayer precursors were in situ heated at 750 °C,
850 °C and 950 °C for 11 minutes in the Ar gas*
atmosphere.
From X-ray diffraction θ-2θ measurements, 00l
20
40
60
80
oriented La2O2Bi was synthesized at all heating2θ (deg)
temperatures in addition to La2O3 and Bi impurities Fig. 1. X-ray diffraction θ-2θ patterns(Fig. 1), indicating that the oxidation reaction was of thin films after heating treatment.
caused by residual oxygen. The epitaxial growth of
La2O2Bi thin films was confirmed by  scan
14.00
2.0
measurement. The c-axis length of La2O2Bi
1.8
epitaxial thin films was linearly expanded from
13.98
1.6
13.934 Å to 13.995 Å with increasing heating
temperature (Fig. 2), suggesting that high heating
13.96
1.4
temperature realized large amount of excess
1.2
oxygen. The full width at half maximum (FWHM)
13.94
1.0
of rocking curve for the 006 diffraction of La2O2Bi
13.92
0.8
monotonically decreased from 1.9° to 0.9° with
750
850
950
increasing heating temperature (Fig. 2), indicating
Heating Temperature (ºC)
that high heating temperature improved film
crystallinity. In the poster, we will discuss film
Fig.
2.
Heating
temperaturesynthesis using other structure precursors.
dependence of c-axis length and
FWHM of rocking curve (RC) for
La2O2Bi epitaxial thin films.

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Phone: +81-22-217-5971
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