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Isshiki, Hironari; Suzuki, Kazuya; Imai, Masaki; Dong, Z.*; Chudo, Hiroyuki; Otani, Yoshichika; Takanashi, Koki; Ieda, Junichi
High Entropy Alloys & Materials, 8 Pages, 2026/00
Wada, Kazuma*; Kazama, Hiroyuki*; Abe, Chikage*; Onishi, Takashi; Yamamoto, Masahiko; Taguchi, Shigeo; Kuno, Takehiko; Maeda, Koji; Idemitsu, Kazuya*; Suzuki, Tatsuya*
Journal of Radioanalytical and Nuclear Chemistry, 334(11), p.8961 - 8968, 2025/11
Times Cited Count：0 Percentile：0.00(Chemistry, Analytical)The feasibility of using commercially available polyvinylpolypyrrolidone (PVPP) as a pretreatment for mass spectrometry to separate actinides was investigated. Uranium, thorium, and plutonium were used as actinides in the study. Adsorption data for An(IV) and An(VI) were obtained by adsorption experiments in nitric acid. In addition, An(III)/An(IV)/An(VI) mutual separation was successfully performed by a column separation method using PVPP. Furthermore, the elution efficiency of U(VI) was improved by the introduction of carbonate ions. This method may be applicable as a mutual separation for actinide mass spectrometry.
Suzuki, Kazuya; Kubota, Takahide*; Takanashi, Koki
APL Materials (Internet), 13(10), p.101108_1 - 101108_6, 2025/10
Times Cited Count：0 Percentile：0.00(Nanoscience & Nanotechnology)The structural, magnetic, and magneto-transport properties of ferromagnetic FeCoNiCuPd high-entropy alloy (HEA) thin films were investigated to assess the role of the heavy element Pd in magneto-transport. The FeCoNiCuPd films with varying composition ratios of Cu and Pd were fabricated by a co-sputtering process at ambient temperature, and the resulting films exhibited a face-centered cubic structure with a homogenous single phase. All the films exhibited ferromagnetic hysteresis curves with soft magnetic behavior at room temperature. The dependence of the anisotropic magnetoresistance effect and anomalous Hall effect on Pd suggests that heavy metals with large spin-orbit interactions play an important role in the magneto-transport of magnetic HEAs. This finding will facilitate the understanding of the magneto-transport phenomenon in magnetic HEAs for future spintronic materials.
Kubota, Takahide*; Suzuki, Kazuya; Hirayama, Yoshiyuki*; Takahashi, Shigeki*; Takanashi, Koki
Physical Review Materials (Internet), 9(8), p.084408_1 - 084408_7, 2025/08
Times Cited Count：4 Percentile：61.92(Materials Science, Multidisciplinary)Vu, TheDang*; Shishido, Hiroaki*; Aizawa, Kazuya; Oku, Takayuki; Oikawa, Kenichi; Harada, Masahide; Kojima, Kenji M*; Miyajima, Shigeyuki*; Soyama, Kazuhiko; Koyama, Tomio*; et al.
Nuclear Instruments and Methods in Physics Research A, 1075, p.170425_1 - 170425_9, 2025/06
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Chudo, Hiroyuki; Yokoi, Naoto*; Matsuo, Mamoru; Harii, Kazuya*; Suzuki, Jun*; Imai, Masaki; Sato, Masahiro*; Maekawa, Sadamichi*; Saito, Eiji*
Physical Review Letters, 134(13), p.130603_1 - 130603_5, 2025/04
Times Cited Count：1 Percentile：34.76(Physics, Multidisciplinary)Amano, Yuki; Sachdeva, R.*; Gittins, D.*; Anantharaman, K.*; Lei, S.*; Valentin-Alvarado, L. E.*; Diamond, S.*; Beppu, Hikari*; Iwatsuki, Teruki; Mochizuki, Akihito; et al.
Environmental Microbiome (Internet), 19, p.105_1 - 105_17, 2024/12
Times Cited Count：4 Percentile：39.90(Genetics & Heredity)Vu, TheDang*; Shishido, Hiroaki*; Aizawa, Kazuya; Oku, Takayuki; Oikawa, Kenichi; Harada, Masahide; Kojima, Kenji M*; Miyajima, Shigeyuki*; Soyama, Kazuhiko; Koyama, Tomio*; et al.
IEEJ Transactions on Electrical and Electronic Engineering, 19(11), p.1888 - 1894, 2024/11
Times Cited Count：0 Percentile：0.00(Engineering, Electrical & Electronic)Hirota, Akinari*; Kozuka, Mariko*; Fukuda, Akari*; Miyakawa, Kazuya; Sakuma, Keisuke; Ozaki, Yusuke; Ishii, Eiichi; Suzuki, Yohei*
Microbial Ecology, 87, p.132_1 - 132_15, 2024/10
Times Cited Count：3 Percentile：40.62(Ecology)Deep underground galleries are used to access the deep biosphere in addition to mining and other engineering applications such as geological disposal of radioactive wastes. Fracture networks developed in the excavation damaged zone (EDZ) are concerned to accelerate mass transport, where microbial colonization might be possible due to the availability of space and nutrients. In this study, microbial biofilms at EDZ fractures were investigated by drilling from a 350-m deep gallery and subsequent borehole logging at the Horonobe underground research laboratory (URL). By using microscopic and spectroscopic techniques, the dense colonization of microbial cells was demonstrated at the surfaces of the EDZ fractures with high hydraulic conductivities. 16S rRNA gene sequence analysis revealed the dominance of gammaproteobacterial lineages, the cultivated members of which are aerobic methanotrophs. Near-complete Horonobe groundwater genomes affiliated within the methanotrophic lineages were fully equipped with genes involved in aerobic methanotrophy. Although the mediation of aerobic methanotrophy remains to be demonstrated, microbial O
production was supported by the presence of genes in the near-complete genomes, such as catalase and superoxide dismutase that produce O from reactive oxygen species and a nitric oxide reductase gene with the substitutions of amino acids in motifs. It is concluded that the EDZ fractures provide energetically favorable subsurface habitats to microorganisms.
Vu, TheDang*; Shishido, Hiroaki*; Aizawa, Kazuya; Oku, Takayuki; Oikawa, Kenichi; Harada, Masahide; Kojima, Kenji M*; Miyajima, Shigeyuki*; Soyama, Kazuhiko; Koyama, Tomio*; et al.
Journal of Physics; Conference Series, 2776, p.012009_1 - 012009_9, 2024/06
Ishida, Takekazu*; Vu, TheDang*; Shishido, Hiroaki*; Aizawa, Kazuya; Oku, Takayuki; Oikawa, Kenichi; Harada, Masahide; Kojima, Kenji M*; Miyajima, Shigeyuki*; Koyama, Tomio*; et al.
Journal of Low Temperature Physics, 214(3-4), p.152 - 157, 2024/02
Times Cited Count：1 Percentile：8.64(Physics, Applied)Sud, A.*; Yamamoto, Kei; Suzuki, Kazuya; Mizukami, Shigemi*; Kurebayashi, Hidekazu*
Physical Review B, 108(10), p.104407_1 - 104407_12, 2023/09
Times Cited Count：22 Percentile：82.65(Materials Science, Multidisciplinary)
single crystals based on Bragg-dip analysis using a delay-line superconducting sensorShishido, Hiroaki*; Vu, TheDang*; Aizawa, Kazuya; Kojima, Kenji M*; Koyama, Tomio*; Oikawa, Kenichi; Harada, Masahide; Oku, Takayuki; Soyama, Kazuhiko; Miyajima, Shigeyuki*; et al.
Journal of Applied Crystallography, 56(4), p.1108 - 1113, 2023/08
Times Cited Count：2 Percentile：26.68(Chemistry, Multidisciplinary)
MethanoperedenaceaeNishimura, Hiroki*; Kozuka, Mariko*; Fukuda, Akari*; Ishimura, Toyoho*; Amano, Yuki; Beppu, Hikari*; Miyakawa, Kazuya; Suzuki, Yohei*
Environmental Microbiology Reports (Internet), 15(3), p.197 - 205, 2023/06
Times Cited Count：5 Percentile：34.42(Environmental Sciences)The family Methanoperedenaceae archaea mediate anaerobic oxidation of methane (AOM). We newly developed a high-pressure laboratory incubation system and investigated groundwater from 214- and 249-m deep boreholes at Horonobe Underground Research Laboratory, Japan, where the high and low abundances of Methanoperedenaceae archaea have been revealed, respectively. We incubated the samples amended with or without amorphous Fe(III) and 
C-labelled methane at an in-situ pressure of 1.6 MPa. After three to seven-day incubation, AOM activities were not detected from the 249-m sample but from the 214-m sample. The AOM rates were 93.7
40.6 and 27.737.5 nM/day with and without Fe(III) amendment. Suspended particulates were not visible in the 249-m sample on the filter, while they were abundant and contained amorphous Fe(III) and Fe(III)-bearing phyllosilicates in the 214-m sample. This supports the in-situ activity of Fe(III)-dependent AOM in the deep subsurface borehole.
Suzuki, Kazuya; Mizukami, Shigemi*
AIP Advances (Internet), 13(3), p.035225_1 - 035225_6, 2023/03
Times Cited Count：12 Percentile：67.14(Nanoscience & Nanotechnology)We studied MgO barrier magnetic tunnel junctions (MTJs) comprising perpendicularly magnetized MnGa and FeCoB electrodes. In those perpendicular (
-) MTJs, we utilized thin metastable bcc CoMn alloys for an interlayer between MnGa and MgO to enhance the tunnel magnetoresistance (TMR). Moreover, we investigated the effect of a thin Mg interlayer between MnGa and CoMn. Owing to the interlayer engineering, we achieved a TMR ratio over 100%, the highest value observed for -MTJs with a tetragonal MnGa electrode. Our study contributes to the further development of spintronic devices using -MTJs with various Mn-based tetragonal alloy electrodes.
Isaka, Koji; Suwa, Masayuki; Kimura, Kazuya; Suzuki, Makoto; Ikekame, Yoshinori; Nagadomi, Hideki
JAEA-Technology 2021-039, 48 Pages, 2023/02
JAEA-Technology-2021-039.pdf:6.97MB
JRR-3 Process control system is used from the initial criticality (1990) after remodeling JRR- 3 as equipment used for monitoring and control of flow rate, temperature, pressure, water level, etc. of coolant and operation of nuclear reactor equipment, and it became necessary to renew as the aging progressed and spare parts could not be obtained sufficiently. Upon renewal, from the viewpoint of ensuring conservation of the core such as decay heat removal and minimizing the impact on reactor users and minimizing costs, it is important not to stop long-term reactor shutdown we planned to divide it into three stages and make it on a continuous basis. This report summarizes the renewal plan and renewal work divided into three stages.
Okabayashi, Jun*; Suzuki, Kazuya; Mizukami, Shigemi*
Journal of Magnetism and Magnetic Materials, 564, Part 2, p.170163_1 - 170163_5, 2022/12
Times Cited Count：5 Percentile：25.40(Materials Science, Multidisciplinary)The magnetic atom diffusion at the interface between CoMn alloy and MnGa layer with annealing is studied using X-ray magnetic circular dichroism (XMCD) analysis. We found that the spins in bcc CoMn are coupled parallel to those in perpendicularly magnetized MnGa layer under the as-grown conditions, while the post annealing modulates the interfacial magnetic coupling to antiferromagnetic in Co. The elementspecific hysteresis curves at each absorption edge revealed the large coercive fields in Mn and Co through the exchange coupling with MnGa. After the annealing process, the changes of XMCD spectral line shapes are related to the interfacial reactions promoting the formation of Mn and CoMnGa layers, which is deduced from the analysis oftransmission electron microscopy. The interfacial diffusion of Mn atoms modulates the magnetic exchange coupling between Mn and Co sites and reverses the direction of perpendicular magnetization.
Shishido, Hiroaki*; Nishimura, Kazuma*; Vu, TheDang*; Aizawa, Kazuya; Kojima, Kenji M*; Koyama, Tomio*; Oikawa, Kenichi; Harada, Masahide; Oku, Takayuki; Soyama, Kazuhiko; et al.
IEEE Transactions on Applied Superconductivity, 31(9), p.2400505_1 - 2400505_5, 2021/12
Times Cited Count：1 Percentile：5.02(Engineering, Electrical & Electronic)In this study, we employed a superconducting detector, current-biased kinetic-inductance detector (CB-KID) for neutron imaging using a pulsed neutron source. We employed the delay-line method, and high spatial resolution imaging with only four reading channels was achieved. We also performed wavelength-resolved neutron imaging by the time-of-flight method. We obtained the neutron transmission images of a Gd-Al alloy sample, inside which single crystals of GdAl were grown, using the delay-line CB-KID. Single crystals were well imaged, in both shapes and distributions, throughout the Al-Gd alloy. We identified Gd nuclei via neutron transmissions that exhibited characteristic suppression above the neutron wavelength of 0.03 nm. In addition, the 
Gd resonance dip, a dip structure of the transmission caused by the nuclear reaction between an isotope and neutrons, was observed even when the number of events was summed over a limited area of 15 
m 
12 m. Gd selective imaging was performed using the resonance dip of Gd, and it showed clear Gd distribution even with a limited neutron wavelength range of 1 pm.
Vu, TheDang; Shishido, Hiroaki*; Aizawa, Kazuya; Kojima, Kenji M*; Koyama, Tomio*; Oikawa, Kenichi; Harada, Masahide; Oku, Takayuki; Soyama, Kazuhiko; Miyajima, Shigeyuki*; et al.
Nuclear Instruments and Methods in Physics Research A, 1006, p.165411_1 - 165411_8, 2021/08
Times Cited Count：2 Percentile：20.31(Instruments & Instrumentation)Shishido, Hiroaki*; Vu, TheDang*; Aizawa, Kazuya; Kojima, Kenji M*; Koyama, Tomio*; Oikawa, Kenichi; Harada, Masahide; Oku, Takayuki; Soyama, Kazuhiko; Miyajima, Shigeyuki*; et al.
Journal of Physics; Conference Series, 1975, p.012023_1 - 012023_8, 2021/07
Times Cited Count：0 Percentile：0.00(Engineering, Electrical & Electronic)