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-base GdO
precipitations in a Mg-Zn-Gd alloyIto, Yuto*; Egusa, Daisuke*; Yamaguchi, Masatake; Abe, Eiji*
Materials Transactions, 64(8), p.2022 - 2025, 2023/08
Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)We have found that, during 
scanning transmission electron microscopy observations, heating of a Mg
Zn
Gd
(at.%) alloy at 623K leads to dynamic precipitations of face-centered-cubic ()-based Gd nanoparticles. With the aid of density-functional theory (DFT) calculations, the observed lattice constant of 5.32
, which is larger than that expected for pure -Gd of 5.06, is likely to be due to oxygen atoms inserted at tetrahedral interstitial sites with essentially a fractional occupation. Systematic DFT calculations show possible occurrences of -Gd-based oxide phase with a wide non-stoichiometry range by occupying either tetrahedral or octahedral interstitial positions, being represented as GdO.
Horibe, Sohei*; Shimizu, Hiroki*; Hoshi, Kojiro*; Makiuchi, Takahiko*; Hioki, Tomosato*; Saito, Eiji
Applied Physics Express, 16(7), p.073001_1 - 073001_4, 2023/07
Times Cited Count：0 Percentile：0(Physics, Applied)Umeda, Maki; Chudo, Hiroyuki; Imai, Masaki; Sato, Nana; Saito, Eiji
Review of Scientific Instruments, 94(6), p.063906_1 - 063906_8, 2023/06
Times Cited Count：0 Percentile：0(Instruments & Instrumentation)Meer, H.*; Wust, S.*; Schmitt, C.*; Herrgen, P.*; Fuhrmann, F.*; Hirtle, S.*; Bednarz, B.*; Rajan, A.*; Ramos, R.*; Ni
o, M. A.*; et al.
Advanced Functional Materials, 33(21), p.2213536_1 - 2213536_6, 2023/05
Times Cited Count：0 Percentile：54.89(Chemistry, Multidisciplinary)Zhou, Z.*; Frost, W.*; Lloyd, D. C.*; Seki, Takeshi*; Kubota, Takahide*; Ramos, R.*; Saito, Eiji; Takanashi, Koki; Hirohata, Atsufumi*
Journal of Magnetism and Magnetic Materials, 571, p.170575_1 - 170575_5, 2023/04
Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)Adachi, Hiroto*; Ikeda, Naoshi*; Saito, Eiji
Physical Review B, 107(15), p.155142_1 - 155142_10, 2023/04
Times Cited Count：2 Percentile：75.57(Materials Science, Multidisciplinary)Kikkawa, Takashi*; Saito, Eiji
Annual Review of Condensed Matter Physics, 14, p.129 - 151, 2023/03
Times Cited Count：11 Percentile：85.47(Physics, Condensed Matter)Hirata, Sakiko*; Kusaka, Ryoji; Meiji, Shogo*; Tamekuni, Seita*; Okudera, Kosuke*; Hamada, Shoken*; Sakamoto, Chihiro*; Honda, Takumi*; Matsushita, Kosuke*; Muramatsu, Satoru*; et al.
Inorganic Chemistry, 62(1), p.474 - 486, 2023/01
Times Cited Count：0 Percentile：0.01(Chemistry, Inorganic & Nuclear)Maekawa, Sadamichi; Kikkawa, Takashi*; Chudo, Hiroyuki; Ieda, Junichi; Saito, Eiji
Journal of Applied Physics, 133(2), p.020902_1 - 020902_24, 2023/01
Times Cited Count：9 Percentile：96.84(Physics, Applied)Oyanagi, Koichi*; Takahashi, Saburo*; Kikkawa, Takashi*; Saito, Eiji
Physical Review B, 107(1), p.014423_1 - 014423_8, 2023/01
Times Cited Count：7 Percentile：94.87(Materials Science, Multidisciplinary)Lee, O.*; Yamamoto, Kei; Umeda, Maki; Zollitsch, C. W.*; Elyasi, M.*; Kikkawa, Takashi*; Saito, Eiji; Bauer, G. E. W.*; Kurebayashi, Hidekazu*
Physical Review Letters, 130(4), p.046703_1 - 046703_6, 2023/01
Times Cited Count：5 Percentile：80.44(Physics, Multidisciplinary)
isomers in 
CfOrlandi, R.; Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Ito, Yuta; Suzaki, Fumi; Nagame, Yuichiro*; et al.
Physical Review C, 106(6), p.064301_1 - 064301_11, 2022/12
Times Cited Count：1 Percentile：33.4(Physics, Nuclear)Hoshi, Kojiro*; Hioki, Tomosato*; Saito, Eiji
Applied Physics Letters, 121(21), p.212404_1 - 212404_6, 2022/11
Times Cited Count：2 Percentile：34.67(Physics, Applied)
Fe
O
/Pt heterostructuresIeda, Junichi; Okayasu, Satoru; Harii, Kazuya*; Kobata, Masaaki; Yoshii, Kenji; Fukuda, Tatsuo; Ishida, Masahiko*; Saito, Eiji
IEEE Transactions on Magnetics, 58(8), p.1301106_1 - 1301106_6, 2022/08
Times Cited Count：1 Percentile：22.45(Engineering, Electrical & Electronic)The combination of spin-driven thermoelectric (STE) devices based on spin Seebeck effect (SSE), and radioactive isotopes as heat sources, has potential as a next-generation method of power generation in applications such as power supplies for space probes. However, there has been very limited knowledge available indicating the irradiation tolerance of spin thermoelectric devices. Through analysis using a heavy ion-beam accelerator and the hard X-ray photoemission spectroscopy (HAXPES) measurements, we show that a prototypical STE device based on YFeO/Pt heterostructures has tolerance to irradiation of high-energy heavy-ion beams. We used 320 MeV gold ion beams modeling cumulative damages due to fission products emitted from the surface of spent nuclear fuels. By varying the dose level, we confirmed that the thermoelectric and magnetic properties of the SSE elements are not affected by the ion-irradiation dose up to 
ions/cm
fluence and that the SSE signal is extinguished around 
ions/cm, in which the ion tracks almost fully cover the sample surface. In addition, the HAXPES measurements were performed to understand the effects at the interface of YFeO/Pt. The HAXPES measurements suggest that the chemical reaction that diminishes the SSE signals is enhanced with the increase of the irradiation dose. We share the current understandings of the damage analysis in YFeO/Pt for developing better STE devices applicable to harsh environmental usages.
ambient on threshold voltage stability in 4H-SiC metal-oxide-semiconductor field-effect transistorsHosoi, Takuji*; Osako, Momoe*; Moges, K.*; Ito, Koji*; Kimoto, Tsunenobu*; Sometani, Mitsuru*; Okamoto, Mitsuo*; Yoshigoe, Akitaka; Shimura, Takayoshi*; Watanabe, Heiji*
Applied Physics Express, 15(6), p.061003_1 - 061003_5, 2022/06
Times Cited Count：2 Percentile：34.67(Physics, Applied)The combination of NO annealing and subsequent post-nitridation annealing (PNA) in CO ambient for SiO/SiC structures has been demonstrated to be effective in obtaining both high channel mobility and superior threshold voltage stability in SiC-based metal-oxide-semiconductor field-effect transistors (MOSFETs). N atoms on the SiO side of the SiO/SiC interface incorporated by NO annealing, which are plausible cause of charge trapping sites, could be selectively removed by CO-PNA at 1300
C without oxidizing the SiC. CO-PNA was also effective in compensating oxygen vacancies in SiO, resulting high immunity against both positive and negative bias-temperature stresses.
Cs activity concentration in the aquatic insect 
(Tricoptera: Stenopsychidae) in the Ota River, Fukushima, JapanIshii, Yumiko*; Miura, Hikaru*; Jo, J.*; Tsuji, Hideki*; Saito, Rie; Koarai, Kazuma; Hagiwara, Hiroki; Urushidate, Tadayuki*; Nishikiori, Tatsuhiro*; Wada, Toshihiro*; et al.
PLOS ONE (Internet), 17(5), p.e0268629_1 - e0268629_17, 2022/05
Times Cited Count：3 Percentile：43.07(Multidisciplinary Sciences)We investigated the variability in Cs activity concentration in individual aquatic insects in detritivorous caddisfly () and carnivorous dobsonfly (
) larvae from the Ota River, Fukushima. Caddisfly larvae showed sporadically higher radioactivity, whereas no such outliers were observed in dobsonfly larvae. Autoradiography and scanning electron microscopy analyses confirmed that these caddisfly larvae samples contained radiocesium-bearing microparticles (CsMPs), which are insoluble Cs-bearing silicate glass particles. CsMPs were also found in potential food sources of caddisfly larvae, such as periphyton and drifting particulate organic matter, indicating that larvae may ingest CsMPs along with food particles of similar size. Although CsMPs distribution and uptake by organisms in freshwater ecosystems is relatively unknown, our study demonstrates that CsMPs can be taken up by aquatic insects.
Yokoi, Naoto*; Saito, Eiji
Journal of Magnetism and Magnetic Materials, 545, p.168673_1 - 168673_12, 2022/03
Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)Nakada, Akira; Nakano, Masanao; Kanai, Katsuta; Seya, Natsumi; Nishimura, Shusaku; Nemoto, Masashi; Tobita, Keiji; Futagawa, Kazuo; Yamada, Ryohei; Uchiyama, Rei; et al.
JAEA-Review 2021-062, 163 Pages, 2022/02
JAEA-Review-2021-062.pdf:2.87MB
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2020 to March 2021. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co., Inc. (the trade name was changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016) in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and exceeded the normal range of fluctuation in the monitoring, were evaluated.
Elyasi, M.*; Saito, Eiji; Bauer, G. E. W.*
Physical Review B, 105(5), p.054403_1 - 054403_12, 2022/02
Times Cited Count：7 Percentile：77.62(Materials Science, Multidisciplinary)Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.
Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12
Times Cited Count：6 Percentile：51.19(Geosciences, Multidisciplinary)The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.
