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Kitagawa, Shunsaku*; Tokunaga, Yo; Sakai, Hironori; Kambe, Shinsaku; 11 of others*
Journal of the Physical Society of Japan, 93(12), p.123701_1 - 123701_5, 2024/11
Times Cited Count:1 Percentile:58.36(Physics, Multidisciplinary)Yoshida, Shogo*; Haga, Yoshinori; Fujii, Takuto*; Nakai, Yusuke*; Mito, Takeshi*; 8 of others*
Journal of the Physical Society of Japan, 93(1), p.013702_1 - 013702_5, 2024/01
Times Cited Count:0 Percentile:0.00(Physics, Multidisciplinary)Hanamachi, Yuji*; Walker, C.*; Sasamoto, Hiroshi; Mihara, Morihiro
NIMS Bisai Kozo Kaiseki Purattofuomu Riyo Hokokusho (Internet), 2 Pages, 2023/12
A High-volume Fly ash Silica fume Cement (HFSC) has been considered as the use of concrete support of drift in deep disposal of radioactive wastes. JAEA has been carried out experiments and modeling studies to evaluate chemical stability of C-A-S-H gel synthesized which would be believed as the dominant component of the HFSC. For the modeling purpose, it is necessary to evaluate the chemical composition both of C-A-S-H gel synthesized and accompanied minerals in the experiment. In the year of 2020, Al and
Si NMR measurement were performed to identify Al and Si distribution in the sample and chemical composition of C-A-S-H gel was derived. However, it was impossible to derive the C-A-S-H gel composition having the expected Al/Si molar ratio since there were several accompanied minerals produced in the experiment due to the short term of immersion. This time similar approach to derive C-A-S-H gel composition is adopted using NMR measurement for the sample of longer time (6 months).
Tei, C.; Otaka, Masahiko; Kuwahara, Daisuke*
Chemical Physics Letters, 829, p.140755_1 - 140755_6, 2023/10
Times Cited Count:1 Percentile:15.33(Chemistry, Physical)We were able to detect the nuclear magnetic resonance (NMR) signal of a liquid sodium clinging to the interface of solid metal particles for the first time. In this study, we confirmed the difference in the relaxation times due to the difference in the interactions between liquid sodium and metal particles suspended in the liquid sodium. It was found that the surface of the micro titanium particles and liquid metallic sodium interact physically, not chemically.
Okubo, Takahiro*; Takei, Akihiro*; Tachi, Yukio; Fukatsu, Yuta; Deguchi, Kenzo*; Oki, Shinobu*; Shimizu, Tadashi*
Journal of Physical Chemistry A, 127(4), p.973 - 986, 2023/02
Times Cited Count:6 Percentile:75.51(Chemistry, Physical)The identification of adsorption sites of Cs on clay minerals has been studied in the fields of environmental chemistry. The nuclear magnetic resonance (NMR) experiments allow direct observations of the local structures of adsorbed Cs. The NMR parameters of Cs, derived from solid-state NMR experiments, are sensitive to the local neighboring structures of adsorbed Cs. However, determining the Cs positions from NMR data alone is difficult. This paper describes an approach for identifying the expected atomic positions of Cs adsorbed on clay minerals by combining machine learning (ML) with experimentally observed chemical shifts. A linear ridge regression model for ML is constructed from the smooth overlap of atomic positions descriptor and gauge-including projector augmented wave (GIPAW) ab initio data. The
Cs chemical shifts can be instantaneously calculated from the Cs positions on any clay layers using ML. The inverse analysis from the ML model can derive the atomic positions from experimentally observed chemical shifts.
Fujibayashi, Hiroki*; Nakamine, Genki*; Kinjo, Katsuki*; Kitagawa, Shunsaku*; Ishida, Kenji*; Tokunaga, Yo; Sakai, Hironori; Kambe, Shinsaku; Nakamura, Ai*; Shimizu, Yusei*; et al.
Journal of the Physical Society of Japan, 91(4), p.043705_1 - 043705_4, 2022/03
Times Cited Count:42 Percentile:97.22(Physics, Multidisciplinary)This study investigates the spin susceptibility in U-based superconductor UTe in the superconducting (SC) state by using Knight shift measurements for a magnetic field
along the
axis, which is the magnetic easy axis of UTe
. Although a tiny anomaly ascribed to the SC diamagnetic effect was observed just below the SC transition temperature
, the
-axis Knight shift in the SC state shows no significant decrease, following the extrapolation from the normal-state temperature dependence. This indicates that the spin susceptibility is nearly unchanged below
. Considering the previous Knight shift results for
and
, the dominant SC state is determined to be
in the spin-triplet pairing, which is consistent with the spin anisotropy in the normal state. The present result shows that UTe
is a spin-triplet superconductor with spin degrees of freedom.
Tokunaga, Yo; Sakai, Hironori; Kambe, Shinsaku; Haga, Yoshinori; Tokiwa, Yoshifumi; Opletal, P.; Fujibayashi, Hiroki*; Kinjo, Katsuki*; Kitagawa, Shunsaku*; Ishida, Kenji*; et al.
Journal of the Physical Society of Japan, 91(2), p.023707_1 - 023707_5, 2022/02
Times Cited Count:23 Percentile:91.78(Physics, Multidisciplinary)Te NMR experiments in field (
) applied along the easy magnetization axis (the
-axis) revealed slow electronic dynamics developing in the paramagnetic state of UTe
. The observed slow fluctuations are concerned with a successive growth of long-range electronic correlations below 30
40 K, where the spin susceptibility along the hard magnetization axis (the
-axis) shows a broad maximum. The experiments also imply that tiny amounts of disorder or defects locally disturb the long-range electronic correlations and develop an inhomogeneous electronic state at low temperatures, leading to a low temperature upturn observed in the bulk-susceptibility in
. We suggest that UTe
would be located on the paramagnetic side near an electronic phase boundary, where either the magnetic or Fermi-surface instability would be the origin of the characteristic fluctuations.
Walker, C.*
NIMS Bisai Kozo Kaiseki Purattofuomu Riyo Hokokusho (Internet), 2 Pages, 2021/09
High content fly ash silica fume cement (HFSC) has been considering a candidate low alkali cements for the geological disposal of radioactive waste in Japan. JAEA has been currently performing many experiments and modeling studies relevant to validation for the long-term stability of the C-A-S-H gel which is a dominant component of the HFSC. For developing the C-A-S-H model of hydration and degradation, it is necessary to determine the composition of C-A-S-H gel and accompanied minerals when it reacts with water. In the present subject, the synthesized sample of C-A-S-H gels were analyzed by using the NMR spectra of Al and
Si to determine the coordination of these element in the C-A-S-H gel.
Sakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Zhu, J.-X.*; Ronning, F.*; Thompson, J. D.*; Ramakrishna, S. K.*; Reyes, A. P.*; Suzuki, Kohei*; Oshima, Yoshiki*; et al.
Physical Review B, 104(8), p.085106_1 - 085106_12, 2021/08
Times Cited Count:4 Percentile:25.58(Materials Science, Multidisciplinary)Antiferromagnetism in a prototypical quantum critical metal CeCoIn is known to be induced by slight substitutions of non-magnetic Zn atoms for In. In nominally 7% Zn substituted CeCoIn
, an antiferromagnetic (AFM) state coexists with heavy fermion superconductivity. Heterogeneity of the electronic states is investigated in Zn doped CeCoIn
by means of nuclear quadrupole and magnetic resonances (NQR and NMR). Site-dependent NQR relaxation rates
indicate that the AFM state is locally nucleated around Zn substituents in the matrix of a heavy fermion state, and percolates through the bulk at the AFM transition temperature
. At lower temperatures, an anisotropic superconducting (SC) gap below the SC transition temperature
, and the SC state permeates through the AFM regions via a SC proximity effect. Applying an external magnetic field induces a spin-flop transition near 5 T, reducing the volume of the AFM regions. Consequently, a short ranged inhomogeneous AFM state survives and coexists with a paramagnetic Fermi liquid state at high fields.
Yoshida, Shogo*; Koyama, Takehide*; Yamada, Haruhiko*; Nakai, Yusuke*; Ueda, Koichi*; Mito, Takeshi*; Kitagawa, Kentaro*; Haga, Yoshinori
Physical Review B, 103(15), p.155153_1 - 155153_5, 2021/04
Times Cited Count:1 Percentile:5.04(Materials Science, Multidisciplinary)Nakamine, Genki*; Kinjo, Katsuki*; Kitagawa, Shunsaku*; Ishida, Kenji*; Tokunaga, Yo; Sakai, Hironori; Kambe, Shinsaku; Nakamura, Ai*; Shimizu, Yusei*; Homma, Yoshiya*; et al.
Physical Review B, 103(10), p.L100503_1 - L100503_5, 2021/03
Times Cited Count:46 Percentile:93.43(Materials Science, Multidisciplinary)Okubo, Takahiro*; Yamazaki, Akio*; Fukatsu, Yuta; Tachi, Yukio
Microporous and Mesoporous Materials, 313, p.110841_1 - 110841_11, 2021/01
Times Cited Count:9 Percentile:44.17(Chemistry, Applied)Pore distributions in water-saturated Ca-montmorillonite were investigated using H NMR measurements under various dry densities (0.8 - 1.6 g/cm
) and porewater salinity conditions (deionized water, 0.1 and 1 M CaCl
), at the temperature range of 233 - 303 K. The volume fractions of the interlayer pore including two and three hydrated layers and the non-interlayer pore in compacted Ca-montmorillonite were quantified by NMR relaxometry including
and
distribution analysis, and were compared with NMR cryoporometry and X-ray diffractometry. These analysis provided consistent pictures on the pore distributions in compacted Ca-montmorillonite, in contrast to Na-montmorillonite. The main factor affecting the pore distribution in compacted Ca- and Na-montmorillonite is the density, whereas the effect of porewater salinity is relatively smaller. The effect of interlayer cations is also relatively smaller at higher density, although the differences in the pore structures are significant at low density.
Imai, Masaki; Chudo, Hiroyuki; Matsuo, Mamoru; Maekawa, Sadamichi; Saito, Eiji
Physical Review B, 102(1), p.014407_1 - 014407_5, 2020/07
Times Cited Count:7 Percentile:36.02(Materials Science, Multidisciplinary)Lessux, G. G.*; Sakai, Hironori; Hattori, Taisuke*; Tokunaga, Yo; Kambe, Shinsaku; Kuhns, P. L.*; Reyes, A. P.*; Thompson, J. D.*; Pagliuso, P. G.*; Urbano, R. R.*
Physical Review B, 101(16), p.165111_1 - 165111_6, 2020/04
Times Cited Count:8 Percentile:40.43(Materials Science, Multidisciplinary)CeRhIn is a Kondo-lattice prototype in which a magnetic field
31T induces an abrupt Fermi-surface (FS) reconstruction and pronounced in-plane electrical transport anisotropy all within its antiferromagnetic state. Here we report low-temperature nuclear magnetic resonance (NMR) measurements revealing a pronounced decrease in the
In formal Knight shift, without changes in crystal or magnetic structures, of CeRhIn
at fields (
) spanning
. We discuss the emergent state above
in terms of a change in Ce's 4
orbitals that arises from field-induced evolution of crystal-electric field (CEF) energy levels. This change in orbital character enhances hybridization between the 4
and the conduction electrons that leads ultimately to an itinerant quantum-critical point at
50T.
Sakai, Hironori; Tokunaga, Yo; Haga, Yoshinori; Kambe, Shinsaku; Ramakrishna, S. K.*; Reyes, A. P.*; Rosa, P. F. S.*; Ronning, F.*; Thompson, J. D.*; Fisk, Z.*; et al.
JPS Conference Proceedings (Internet), 30, p.011169_1 - 011169_6, 2020/03
Uranium disulfide -US
showing a semimetal-to-semiconductor crossover has been investigated by the nuclear magnetic resonance (NMR) technique for
S nuclei with the nuclear spin of
. Since the natural concentration 0.76% of NMR active
S nuclei is too dilute, the isotopic enrichment to
50% has been carried out for the single crystal growth. The
S NMR spectra have been successfully obtained using a single crystal of
-US
with external fields along the crystallographic
axis. The S sites assignments have been made based on these NMR spectra.
Aoyama, Taisuke*; Kotegawa, Hisashi*; To, Hideki*; Kimura, Noriaki*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika*
Physica B; Condensed Matter, 570, p.349 - 351, 2019/10
Times Cited Count:0 Percentile:0.00(Physics, Condensed Matter)Aoyama, Taisuke*; Kotegawa, Hisashi*; Kimura, Noriaki*; Yamamoto, Etsuji; Haga, Yoshinori; Onuki, Yoshichika*; To, Hideki*
Journal of the Physical Society of Japan, 88(6), p.064706_1 - 064706_7, 2019/06
Times Cited Count:1 Percentile:10.17(Physics, Multidisciplinary)Dioguardi, A. P.*; Yasuoka, Hiroshi*; Thomas, S. M.*; Sakai, Hironori; Cary, S. K.*; Kozimor, S. A.*; Albrecht-Schmitt, T. E.*; Choi, H. C.*; Zhu, J.-X.*; Thompson, J. D.*; et al.
Physical Review B, 99(3), p.035104_1 - 035104_6, 2019/01
Times Cited Count:10 Percentile:40.12(Materials Science, Multidisciplinary)We present a detailed nuclear magnetic resonance (NMR) study of Pu in bulk and powdered single-crystal plutonium tetraboride (PuB
), which has recently been investigated as a potential correlated topological insulator. The
Pu NMR spectra are consistent with axial symmetry of the shift tensor showing for the first time that
Pu NMR can be observed in an anisotropic environment and up to room temperature. The temperature dependence of the
Pu shift, combined with a relatively long spin-lattice relaxation time (
), indicate that PuB
adopts a nonmagnetic state with gaplike behavior consistent with our density functional theory calculations. The temperature dependencies of the NMR Knight shift and
imply bulk gaplike behavior confirming that PuB
is a good candidate topological insulator.
Kambe, Shinsaku; Tokunaga, Yo; Sakai, Hironori; Hattori, Taisuke; Higa, Nonoka; Matsuda, Tatsuma*; Haga, Yoshinori; Walstedt, R. E.*; Harima, Hisatomo*
Physical Review B, 97(23), p.235142_1 - 235142_10, 2018/06
Times Cited Count:22 Percentile:67.29(Materials Science, Multidisciplinary)Okubo, Takahiro*; Ibaraki, Moe*; Tachi, Yukio; Iwadate, Yasuhiko*
Applied Clay Science, 123, p.148 - 155, 2016/04
Times Cited Count:34 Percentile:75.45(Chemistry, Physical)The pore distribution of water-saturated compacted clay (Na-montmorillonite at 0.8 and 1.4 g/cm saturated by three salt concentrations) was evaluated using
H NMR relaxometry and freezing point depression. The populations of interlayer water with four hydrated state and non-interlayer water were calculated from the assumed thresholds. The sample with lower density exhibits higher population of non-interlayer water up to 55%. Low-temperature
H NMR experiments in view of freezing point depression indicated that mesopore water in approximately 4 nm space observed in the calorimetric study was considered as non-interlayer water and the threshold temperature. The result showed that population of non-interlayer water by expected from freezing point depression agreed with
H NMR relaxometry within 10%. Correlation experiments between longitudinal (
) and transverse relation times (
) at -10
C suggested that high-mobility bulk-like water molecules existed at a clay density of 1.4 g/cm
.