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Ieda, Junichi; Araki, Yasufumi; Yamane, Yuta*
Kotai Butsuri, 59(8), p.403 - 410, 2024/08
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
Times Cited Count：5 Percentile：93.84(Physics, Multidisciplinary)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 Mn
Sn 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.
Araki, Yasufumi; Ieda, Junichi
Journal of the Physical Society of Japan, 92(7), p.074705_1 - 074705_9, 2023/06
Times Cited Count：0 Percentile：0.00(Physics, Multidisciplinary)Topological electromagnetism owing to nontrivial momentum-space topology of electrons in insulators gives rise to diverse anomalous magnetoelectric responses. While conventional inductors and capacitors are based on classical electromagnetism described by Maxwell's equations, here we show that topological electromagnetism in combination with spin dynamics in magnets also generates an inductance or a capacitance. We build a generic framework to extract the complex impedance on the basis of topological field theory, and demonstrate the emergence of an inductance or a capacitance in several heterostructure setups. In comparison with the previously-studied emergent inductances in metallic magnets, insulators highly suppress the power loss, because of the absence of Joule heating. We show that the inductance from topological electromagnetism is achieved at low current and high frequency, and is also advantageous in its power efficiency, as characterized by the high quality factor (Q-factor).
Yamanouchi, Michihiko*; Araki, Yasufumi; Sakai, Takaki*; Uemura, Tetsuya*; Ota, Hiromichi*; Ieda, Junichi
Science Advances (Internet), 8(15), p.eabl6192_1 - eabl6192_6, 2022/04
Times Cited Count：7 Percentile：69.49(Multidisciplinary Sciences)In a ferromagnetic Weyl metal SrRuO, a large effective magnetic field 
exerted on a magnetic domain wall (DW) by current has been reported. We show that the ratio of to current density exhibits nonmonotonic temperature dependence and surpasses those of conventional spin-transfer torques and spin-orbit torques. This enhancement is described well by topological Hall torque (THT), which is exerted on a DW by Weyl electrons emerging around Weyl points when an electric field is applied across the DW. The ratio of the arising from the THT to current density is over one order of magnitude higher than that originating from spin-transfer torques and spin-orbit torques reported in metallic systems, showing that the THT may provide a better way for energy-efficient manipulation of magnetization in spintronics devices.
Araki, Yasufumi; Ieda, Junichi
Physical Review Letters, 127(21), p.277205_1 - 277205_7, 2021/12
Times Cited Count：5 Percentile：48.07(Physics, Multidisciplinary)Momentum-space topology of electrons under strong spin-orbit coupling contributes to the electrically induced torques exerting on magnetic textures insensitively to disorder or thermal fluctuation. We present a direct connection between band topology and the torques by classifying the whole torques phenomenologically. As well as the intrinsic anomalous Hall effect, the torques also emerge intrinsically from the anomalous velocity of electrons regardless of a nonequilibrium transport current. We especially point out the intrinsic contribution arising exclusively in magnetic textures, which we call the "topological Hall torque (THT)". The THT emerges in bulk crystals without any interface or surface structures. We numerically demonstrate the enhancement of the THT in comparison with the conventional spin-transfer torque in the bulk metallic ferromagnet, which accounts for the giant current-induced torque measured in ferromagnetic 
.
Oto, Tsutomu; Asano, Norikazu; Kawamata, Takanori; Yanai, Tomohiro; Nishimura, Arashi; Araki, Daisuke; Otsuka, Kaoru; Takabe, Yugo; Otsuka, Noriaki; Kojima, Keidai; et al.
JAEA-Review 2020-018, 66 Pages, 2020/11
JAEA-Review-2020-018.pdf:8.87MB
A collapse event of the cooling tower of secondary cooling system in the JMTR (Japan Materials Testing Reactor) was caused by the strong wind of Typhoon No.15 on September 9, 2019. The cause of the collapse of the cooling tower was investigated and analyzed. As the result, it was identified that four causes occurred in combination. Thus, the soundness of the cooling tower of Utility Cooling Loop (UCL cooling tower), which is a wooden cooling tower installed at the same period as the cooling tower of secondary cooling system, was investigated. The items of soundness survey are to grasp the operation conditions of the UCL cooling tower, to confirm the degradation of structural materials, the inspection items and inspection status of the UCL cooling tower, and to investigate the past meteorological data. As the results of soundness survey of the UCL cooling tower, the improvement of inspection items of the UCL cooling tower was carried out and the replacement and repair of the structural materials of the UCL cooling tower were planned for safe maintenance and management of this facility. And the renewal plan of new cooling tower was created to replace the existing UCL cooling tower. This report is summarized the soundness survey of the UCL cooling tower.
Nagai, Ryoji; Hajima, Ryoichi; Shizuma, Toshiyuki; Mori, Michiaki; Akagi, Tomoya*; Kosuge, Atsushi*; Honda, Yosuke*; Araki, Sakae*; Terunuma, Nobuhiro*; Urakawa, Junji*
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1328 - 1330, 2015/09
Accelerator and laser technologies required for laser Compton scattering (LCS) photon source based on an energy-recovery linac (ERL) have been developed at the Compact ERL (cERL) facility. A high-flux, energy tunable, and monochromatic photon source such as the ERL-based LCS photon source is necessary for nondestructive assay of nuclear materials. For the demonstration of the ERL-based LCS photon generation, a laser enhancement cavity was installed at the recirculation loop of the cERL. The electron beam energy, the laser wavelength, and the collision angle are 20 MeV, 1064 nm, and 18 
, respectively. The calculated maximum energy of the LCS photons is about 7 keV. A silicon drift detector (SDD) with active area of 17 mm
placed 16.6 m from the collision point was used for observation of the LCS photons. As a result of the measurement, the flux on the detector, central energy, and energy width of the LCS photons were obtained as 1200/s, 6.91 keV, and 81 eV, respectively.
Nagai, Ryoji; Hajima, Ryoichi; Mori, Michiaki; Shizuma, Toshiyuki; Akagi, Tomoya*; Araki, Sakae*; Honda, Yosuke*; Kosuge, Atsushi*; Terunuma, Nobuhiro*; Urakawa, Junji*
Proceedings of 6th International Particle Accelerator Conference (IPAC '15) (Internet), p.1607 - 1609, 2015/06
Accelerator and laser technologies required for laser Compton scattering (LCS) photon source based on an energy-recovery linac (ERL) have been developed at the Compact ERL (cERL) facility. A high-flux, energy tunable, and monochromatic photon source such as the ERL-based LCS photon source is necessary for nondestructive assay of nuclear materials. For the demonstration of the ERL-based LCS photon generation, a laser enhancement cavity was installed at the recirculation loop of the cERL. The electron beam energy, the laser wavelength, and the collision angle are 20 MeV, 1064 nm, and 18 deg., respectively. The calculated maximum energy of the LCS photons is about 7 keV. A silicon drift detector (SDD) with active area of 17 mm placed 16.6 m from the collision point was used for observation of the LCS photons. As a result of the measurement, the flux on the detector, central energy, and energy width of the LCS photons were obtained as 1200 /s, 6.91 keV, and 81 eV, respectively.
Yamazaki, Yoshio; Hirano, Koichiro*; Fukuda, Satoshi*; Takano, Mikio*; Araki, Sakae*; Terunuma, Nobuhiro*; Urakawa, Junji*
Proceedings of 9th European Particle Accelerator Conference (EPAC 2004), 0 Pages, 2004/07
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
Sato, Shinichi*; Araki, Masanori; Omori, Junji*; Oono, Isamu*; Sato, Satoshi; Yamauchi, Michinori*; Nishitani, Takeo
JAERI-Tech 2002-083, 126 Pages, 2002/10
JAERI-Tech-2002-083.pdf:4.07MB
It is one of the foremost goals for ITER to demonstrate the attractiveness with regard to safety and environmental potential. This implies that the radioactive materials and waste at decommissioning phase should carefully be treated with prescribed regulations. As possible activities during the Coordinated Technical Activity (CTA), Japanese Participant Team (JA-PT) has proposed a study for searching the possibility of more reduction in the activated level by taking account of minimum material changes while keeping original design concept and structure. Based on it, reassessment of the activation level and the amount of activation volumes will give us positive aspects for public acceptance.
Omori, Junji*; Kitamura, Kazunori*; Araki, Masanori; Oono, Isamu*; Shoji, Teruaki
JAERI-Tech 2002-053, 86 Pages, 2002/07
JAERI-Tech-2002-053.pdf:3.81MB
no abstracts in English
Mori, Masahiro; Shoji, Teruaki; Araki, Masanori; Saito, Keiji*; Senda, Ikuo; Omori, Junji*; Sato, Shinichi*; Inoue, Takashi; Ono, Isamu*; Kataoka, Takahiro*; et al.
Nihon Genshiryoku Gakkai-Shi, 44(1), p.16 - 89, 2002/01
no abstracts in English
Araki, Masanori; Sato, Shinichi*; Senda, Ikuo; Omori, Junji*; Shoji, Teruaki
Fusion Engineering and Design, 58-59, p.887 - 892, 2001/11
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)no abstracts in English
Omori, Junji*; Araki, Masanori
JAERI-Tech 2000-006, p.15 - 0, 2000/02
JAERI-Tech-2000-006.pdf:0.66MB
no abstracts in English
中島 準作; 荒木 克彦; 三木 博実
福岡 廣一*
JP, 2009-274186 Patent licensing information Patent publication (In Japanese)
【課題】刃物鋼として使用するための焼き入れ硬化処理を行なっても、クラッド接合部からの層間剥離を起こさず、しかも軽量性と耐食性及び耐久性に優れたチタン材料で構成した使い易いチタンクラッド鋼刃物及びその製造方法を提供する。 【解決手段】ステンレス刃物鋼材1と、チタン系材料で構成する刃物外皮材5と、前記ステンレス刃物鋼材と前記刃物外皮材との間に、ステンレス刃物鋼材ならびに刃物外皮材とは異なる複数の材料を重ね合わせてクラッド材としたチタンクラッド刃物鋼であって、前記ステンレス刃物鋼材ならびに刃物外皮材とは異なる複数の材料は、ステンレス刃物鋼材側から、銅合金の第3中間層2、MOの第2中間層3、V族元素金属の第1中間層4の順に重ね合わせたチタンクラッド刃物であり、特に熱間圧延工程の前段階で真空脱気を行う製造方法により、クラッド接合部からの層間剥離を起こさない軽量性と耐食性及び耐久性に優れたチタン材料で構成したチタンクラッド鋼とし、良質な刃物用材とする。
中島 準作; 吉井 文男; 荒木 克彦; 笠井 昇; 三木 博実; 玉脇 宏
石川 浩*
JP, 2010-081718 Patent licensing information Patent publication (In Japanese)
【課題】ハイドロゲルが有する高い定着効果によって、消臭効果と持続性に優れ、かつ水洗による再使用が可能な高機能性消臭和紙および当該消臭和紙の製造方法を提供する。 【解決手段】本発明に係る高機能性消臭和紙は、和紙に、消臭剤としてのヨウ素アニオン交換樹脂および当該消臭剤の効果を長期的に安定持続させるためのトルマリンを、ハイドロゲルによって定着してなることを特徴とする。
吉井 文男; 中島 準作; 荒木 克彦; 玉脇 宏; 笠井 昇
内田 長信*; 山本 弘行*
JP, 2010-206186 Patent licensing information Patent publication (In Japanese)
【課題】接着剤を用いることなく和紙原料をパネルなどの建築資材に被覆することが可能な和紙被覆建築資材の製造方法を提供する。 【解決手段】本発明の和紙被覆建築資材の製造方法は、水にハイドロゲルを添加したハイドロゲル添加水と和紙原料とを含む溶液を調整する調整工程と、前記調整工程で調整された前記溶液を建築資材に吹き付けて被覆を形成する被覆形成工程と、前記被覆形成工程によって被覆が形成された建築資材の乾燥を行う乾燥工程と、を有することを特徴とする。
中島 準作; 荒木 克彦; 井上 賢紀
福岡 廣一*; 坪川 翼*
JP, 2011-203101 Patent licensing information Patent publication (In Japanese)
【課題】柔らかい食材は勿論硬い食材を切ることができ、切れ味が良く、切れ味が永く持続し、折れ難く、錆難い安価な刃物を実現する。 【解決手段】チタン粉末と炭化ケイ素粉末とを混合してMA処理したMA材を、チタン板で形成した筐体に充填して密封し、これを熱間圧延してチタン刃物材とし、このチタン刃物材を構成するチタン粉末刃物材(MA材)を焼結した後に研削することにより刃付けしたチタン刃物とするものであり、前記MA材によって構成されるチタン粉末刃物材の両側面には前記チタン板によるチタン側板が配された構成とする。
荒木 康史; 家田 淳一
山根 結太*; 深見 俊輔*
JP, 2022-183158 Patent licensing information
【課題】 電気回路内に実装するに際して、動作電流を小さくしつつも、十分な創発インダクタ機能を発現できる薄膜インダクタ素子を提供することを目的とする。 【解決手段】 磁性体層と、非磁性体層と、が積層された積層膜と、一対の電極を備え、前記磁性体層と前記非磁性体層は、積層方向と直交する方向で任意の形状で延伸され、前記磁性体層は、積層方向成分を含む略一様な磁化構造を有しており、前記非磁性体層は、絶縁体であり、かつその表面が導電可能な構造であり、前記一対の電極は、前記積層膜が延伸される両端近傍であり、少なくとも前記非磁性体層の表面に接する位置に設けられ、1KHZ~1GHZの周波数で変調する電流が印加されるものであることを特徴とする薄膜インダクタ素子。
荒木 康史; 家田 淳一
山根 結太*; 深見 俊輔*
JP, PCT/JP2023/019706 Patent licensing information
電気回路内に実装するに際して、動作電流を小さくしつつも、十分な創発インダクタ機能を発現できる薄膜インダクタ素子を提供することを目的とする。 磁性体層と、非磁性体層と、が積層された積層膜と、一対の電極を備え、前記磁性体層と前記非磁性体層は、積層方向と直交する方向で任意の形状で延伸され、前記磁性体層は、積層方向成分を含む略一様な磁化構造を有しており、前記非磁性体層は、絶縁体であり、かつその表面が導電可能な構造であり、前記一対の電極は、前記積層膜が延伸される両端近傍であり、少なくとも前記非磁性体層の表面に接する位置に設けられ、1KHZ~1GHZの周波数で変調する電流が印加されるものであることを特徴とする薄膜インダクタ素子。
