Room-temperature flexible manipulation of the quantum-metric structure in a topological chiral antiferromagnet

Han, J.*; Uchimura, Tomohiro*; Araki, Yasufumi; Yoon, J.-Y.*; Takeuchi, Yutaro*; Yamane, Yuta*; Kanai, Shun*; Ieda, Junichi; Ohno, Hideo*; Fukami, Shunsuke*

Nature Physics, 20(7), p.1110 - 1117, 2024/07

https://doi.org/10.1038/s41567-024-02476-2

Quantum metric and Berry curvature are two fundamental and distinct factors to describe the geometry of quantum eigenstates. While Berry curvature is known for playing crucial roles in several condensed-matter states, quantum metric, which was predicted to induce new classes of topological phenomena, has rarely been touched, particularly in an ambient circumstance. Using a topological chiral antiferromagnet MnSn adjacent to Pt, at room temperature, we successfully manipulate the quantum-metric structure of electronic states through its interplay with the nanoscale spin texture at the MnSn/Pt interface. This is manifested by a time-reversal-odd second-order Hall effect that is robust against extrinsic electron scattering, in contrast to any transport effects from the Berry curvature. We also verify the flexibility of controlling the quantum-metric structure, as the interacting spin texture can be tuned by moderate magnetic fields or by interface engineering via spin-orbit interactions. Our work paves a way for harnessing the quantum-metric structure to unveil emerging topological physics in practical environments and to build applicable nonlinear devices.

Intruder configurations in Ne at the transition into the island of inversion; Detailed structure study of Ne

Wang, H.*; Yasuda, Masahiro*; Kondo, Yosuke*; Nakamura, Takashi*; Tostevin, J. A.*; Ogata, Kazuyuki*; Otsuka, Takaharu*; Poves, A.*; Shimizu, Noritaka*; Yoshida, Kazuki; et al.

Physics Letters B, 843, p.138038_1 - 138038_9, 2023/08

https://doi.org/10.1016/j.physletb.2023.138038

Detailed -ray spectroscopy of the exotic neon isotope Ne has been performed using the one-neutron removal reaction from Ne. Based on an analysis of parallel momentum distributions, a level scheme with spin-parity assignments has been constructed for Ne and the negative-parity states are identified for the first time. The measured partial cross sections and momentum distributions reveal a significant intruder p-wave strength providing evidence of the breakdown of the N = 20 and N = 28 shell gaps. Only a weak, possible f-wave strength was observed to bound final states. Large-scale shell-model calculations with different effective interactions do not reproduce the large p-wave and small f-wave strength observed experimentally, indicating an ongoing challenge for a complete theoretical description of the transition into the island of inversion along the Ne isotopic chain.

Thermophysical properties of molten (FeO)-(SiO) measured by aerodynamic levitation

Kondo, Toshiki; Toda, Taro*; Takeuchi, Junichi*; Kikuchi, Shin; Kargl, F.*; Muta, Hiroaki*; Oishi, Yuji*

High Temperatures-High Pressures, 52(3-4), p.307 - 321, 2023/06

https://doi.org/10.32908/hthp.v52.1405

In order to establish an evaluation method/numerical simulation for nuclear reactor safety under severe accidental conditions, it is necessary to obtain the physical properties, especially fluidity of the relevant molten materials at very high temperatures. In this study, thermophysical properties such as density and viscosity were obtained for (FeO)-(SiO), which is a representative composition in the early stage of severe accident. (FeO)-(SiO) is produced by the contact between the molten oxide of steel, which is the main component of the reactor, and SiO, which is the main component of concrete. As a result, the physical properties of the (FeO)-(SiO) mixture were almost the same as those of FeO obtained in previous studies, and it could be concluded that a small amount of SiO (about 5 mol.%) did not significantly affect the fluidity of FeO.

Thermophysical properties of molten FeO, (FeO)-(ZrO) and (FeO)-(UO)

Kondo, Toshiki; Toda, Taro*; Takeuchi, Junichi*; Kargl, F.*; Kikuchi, Shin; Muta, Hiroaki*; Oishi, Yuji*

Journal of Nuclear Science and Technology, 59(9), p.1139 - 1148, 2022/09

https://doi.org/10.1080/00223131.2022.2032445

no abstracts in English

Development of stabilization treatment technology for radioactive aluminum waste

Seki, Misaki; Fujita, Yoshitaka; Fujihara, Yasuyuki*; Zhang, J.*; Yoshinaga, Hisao*; Sano, Tadafumi*; Hori, Junichi*; Nagata, Hiroshi; Otsuka, Kaoru; Omori, Takazumi; et al.

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 29(1), p.2 - 9, 2022/06

https://doi.org/10.3327/jnuce.29.1_2

no abstracts in English

Chiral-spin rotation of non-collinear antiferromagnet by spin-orbit torque

Takeuchi, Yutaro*; Yamane, Yuta*; Yoon, J.-Y.*; Ito, Ryuichi*; Jinnai, Butsurin*; Kanai, Shun*; Ieda, Junichi; Fukami, Shunsuke*; Ohno, Hideo*

Nature Materials, 20(10), p.1364 - 1370, 2021/10

https://doi.org/10.1038/s41563-021-01005-3

Case studies of radiation dose assessment in emergency situation of nuclear facilities

Kawasaki, Masatsugu; Nakajima, Junya; Yoshida, Keisuke; Kato, Saori; Nishino, Sho; Nozaki, Teo; Nakagawa, Masahiro; Tsunoda, Junichi; Sugaya, Yuki; Hasegawa, Rie; et al.

JAEA-Data/Code 2017-004, 57 Pages, 2017/03

JAEA-Data-Code-2017-004.pdf:2.34MB

In emergency situation of nuclear facilities, we need to estimate the radiation dose due to radiation and radioactivity to grasp the influence range of the accident in the early stage. Therefore, we prepare the case studies of dose assessment for public exposure dose and personal exposure dose and contribute them to emergency procedures. This document covers about accidents of nuclear facilities in Nuclear Science Research Institute and past accident of nuclear power plant, and it can be used for inheritance of techniques of emergency dose assessment.

Absolute measurement of D-T neutron flux with a monitor using activation of flowing water

Uno, Yoshitomo; Kaneko, Junichi; Nishitani, Takeo; Maekawa, Fujio; Tanaka, Teruya; Shibata, S.*; Ikeda, Yujiro; Khripunov, V.*; Walker, C. I.*; Ebisawa, Katsuyuki*; et al.

Fusion Engineering and Design, 56-57, p.895 - 898, 2001/10

https://doi.org/10.1016/S0920-3796(01)00373-8

no abstracts in English

Neutronics experiments for ITER at JAERI/FNS

Konno, Chikara; Maekawa, Fujio; Kasugai, Yoshimi; Uno, Yoshitomo; Kaneko, Junichi; Nishitani, Takeo; Wada, Masayuki*; Ikeda, Yujiro; Takeuchi, Hiroshi

Nuclear Fusion, 41(3), p.333 - 337, 2001/03

https://doi.org/10.1088/0029-5515/41/3/311

no abstracts in English

Technical feasibility study in a fusion power monitor based on activation of water flow

Kaneko, Junichi; Uno, Yoshitomo; Nishitani, Takeo; Maekawa, Fujio; Tanaka, Teruya; Shibata, Yoshinari; Ikeda, Yujiro; Takeuchi, Hiroshi

Review of Scientific Instruments, 72(1), p.809 - 813, 2001/01

https://doi.org/10.1063/1.1320996

no abstracts in English