Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Mascari, F.*; Bersano, A.*; Woods, B. G.*; Reyes, J. N.*; Welter, K.*; Nakamura, Hideo; D'Auria, F.*
Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 16 Pages, 2022/03
; 
In NQR/NMR and 
Co NMR studySakai, 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：6 Percentile：22.56(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.
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：11 Percentile：42.92(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.
S nuclear magnetic resonance spectra of uranium disulfide 
-US
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.
Haneklaus, N.*; Reyes, R.*; Lim, W. G.*; Tabora, E. U.*; Palattao, B. L.*; Petrache, C.*; Vargas, E. P.*; Kunitomi, Kazuhiko; Ohashi, Hirofumi; Sakaba, Nariaki; et al.
Philippine Journal of Science, 144(1), p.69 - 79, 2015/06
The Philippines may profit from extracting uranium (U) from phosphoric acid during fertilizer production in a way that the recovered U can be beneficiated and taken as raw material for nuclear reactor fuel. Used in a high temperature reactor (HTR) that provides electricity and/or process heat for fertilizer processing and U extraction, energy-neutral fertilizer production, an idea first proposed by Haneklaus et al., is possible. This paper presents a first case study of the concept regarding a representative phosphate fertilizer plant in the Philippines and exemplary HTR designs (HTR50S and GTHTR300C) developed by the Japan Atomic Energy Agency (JAEA). Three different arrangements (version I-III), ranging from basic electricity supply to overall power supply including on site hydrogen production for ammonia conversion, are introduced and discussed.
Mirabueno, M. H. T.*; Torii, Masayuki*; Laguerta, E. P.*; Delos Reyes, P. J.*; Fujiki, Toshiyuki*; Bariso, E. B.*; Okuno, Mitsuru*; Nakamura, Toshio*; Danhara, Toru*; Kokubu, Yoko; et al.
Chigaku Zasshi, 123(5), p.751 - 760, 2014/10
Core drilling at site IRBH-2 within Irosin caldera, southern Luzon, reached 50 m. Systematic logging and documentation were done to describe the sediments. AMS 
C dates were obtained for plant fragments from the peaty layers. Lahars and fluvial deposits were the predominant deposits in the core sequence. The upper 12 m was comprised mostly by andesitic fluvial and minor lahars. Eight fallouts were intercalated with reworked sediments from depth interval of 20 to 50 m. The refractive index measurement of analyzed samples indicated that post-caldera eruptions generated andesite, dacite and minor rhyolite. The similarity in petrographic characteristics between the rhyolite fallout and the Irosin ignimbrite indicates that small-scale eruptions involving magma from the caldera event occurred during post-caldera stage.Young radiocarbon dates obtained from the peaty layers shows that volcaniclastic deposits in the upper levels were likely derived from the eruptions of Bulusan volcano.
Si; High magnetic field nuclear magnetic resonance to 40 TSakai, Hironori; Urbano, R. R.*; Tokunaga, Yo; Kambe, Shinsaku; Suzuki, Michito; Kuhns, P. L.*; Reyes, A. P.*; Tobash, P. H.*; Ronning, F.*; Bauer, E. D.*; et al.
Physical Review Letters, 112(23), p.236401_1 - 236401_5, 2014/06
Times Cited Count：7 Percentile：45.78(Physics, Multidisciplinary)Very high field 
Si-NMR measurements using a fully Si-enriched URuSi single crystal were carried out in order to microscopically investigate the "hidden order" (HO) state and adjacent magnetic phases in the high field limit. At the lowest measured temperature of 0.4 K, a clear anomaly reflecting a Fermi surface instability near 22 T inside the HO state is detected by the Si shift, 
. Moreover, a strong enhancement of develops near a critical field 
T, and the Si-NMR signal disappears suddenly at 
, indicating the total suppression of the HO state. Nevertheless, a weak and shifted Si-NMR signal reappears for fields higher than at 4.2 K, providing evidence for a magnetic structure within the magnetic phase caused by the Ising-type anisotropy of the uranium ordered moments.
Bauer, E. D.*; Yang, Y.-F.*; Capan, C.*; Urbano, R. R.*; Miclea, C. F.*; Sakai, Hironori; Ronning, F.*; Graf, M. J.*; Balatsky, A. V.*; Movshovich, R.*; et al.
Proceedings of the National Academy of Sciences of the United States of America, 108(17), p.6857 - 6861, 2011/04
Times Cited Count：41 Percentile：82.15(Multidisciplinary Sciences)Here, we report a manifestation of electronic inhomogeneity in a strongly correlated -electron system, using CeCoIn as an example. A thermodynamic analysis of its superconductivity, combined with nuclear quadrupole resonance measurements, shows that nonmagnetic impurities (Y, La, Yb, Th, Hg, and Sn) locally suppress unconventional superconductivity, generating an inhomogeneous electronic "Swiss cheese" due to disrupted periodicity of the Kondo lattice. Our analysis may be generalized to include related systems, suggesting that electronic inhomogeneity should be considered broadly in Kondo lattice materials.
Mounce, A. M.*; Oh, S.*; Mukhopadhyay, S.*; Halperin, W. P.*; Reyes, A. P.*; Kuhns, P. L.*; Fujita, Kazuhiro*; Ishikado, Motoyuki; Uchida, Shinichi*
Nature Physics, 7(2), p.125 - 128, 2011/02
Times Cited Count：8 Percentile：48.26It has been predicted that superconducting vortices should be electrically charged and that this effect is particularly enhanced for high-temperature superconductors. Hall effect and nuclear magnetic resonance (NMR) experiments suggest the existence of charge accumulation in the vortex core, but the effects are small and the interpretation controversial. Here we show that the Abrikosov vortex lattice, characteristic of the mixed state of superconductors, will become unstable at a sufficiently high magnetic field if there is charge trapped on the vortex core. Our NMR measurements of the magnetic fields generated by vortices in Bi
SrCaCuO
single crystals provide evidence for an electrostatically driven vortex lattice reconstruction with the magnitude of charge on each vortex pancake of 
, depending on doping, in line with theoretical estimates.
SrCaCuOMounce, A. M.*; Oh, S.*; Mukhopadhyay, S.*; Halperin, W. P.*; Reyes, A. P.*; Kuhns, P. L.*; Fujita, Kazuhiro*; Ishikado, Motoyuki; Uchida, Shinichi*
Physical Review Letters, 106(5), p.057003_1 - 057003_4, 2011/02
Times Cited Count：10 Percentile：51.23(Physics, Multidisciplinary)Competition with magnetism is at the heart of high-temperature superconductivity, most intensely felt near a vortex core. To investigate vortex magnetism we have developed a spatially resolved probe based upon NMR spin-lattice-relaxation spectroscopy. With this approach we have found a spin-density wave associated with the vortex core in BiSrCaCuO, similar to checkerboard patterns in the local density of electronic states reported from scanning tunneling microscope experiments. We have determined both the spin-modulation amplitude and decay length from the vortex core in fields up to 
= 30 T.
S-NMR study for a narrow-gap semiconductor -USSakai, Hironori; Higa, Nonoka; Hattori, Taisuke; Tokunaga, Yo; Kambe, Shinsaku; Tateiwa, Naoyuki; Haga, Yoshinori; Rossa, P. F. S.*; Thompson, J. D.*; Ronning, F.*; et al.
no journal, ,
-US is known as a narrow-gap semiconductor. The magnetoresistance in this compound is extremely large but anisotropic. To obtain microscopic view of the magnetism, we have carried on S-NMR study. We will discuss the magnetic properties in this system to show the recent NMR results.
Sakai, Hironori; Tokunaga, Yo; Haga, Yoshinori; Kambe, Shinsaku; Zhu, J.-X.*; Ronning, F.*; Ramakrishna, S. K.*; Reyes, A. P.*; Suzuki, Kohei*; Oshima, Yoshiki*; et al.
no journal, ,
Substitutions of In sites by Zn atoms in heavy fermion superconductor CeCoIn is reported to induce an antiferromagnetic order by Yokoyama et al. in Ibaraki University. Near the critical region, non-Fermi-liquid behavior has been observed in magnetization and specific heat. We have performed NMR measurements to reveal the spin fluctuations near the critical region.
-USSakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Ramakrishna, S. K.*; Reyes, A. P.*; Rosa, P. F. S.*; Thompson, J. D.*; Ronning, F.*; Fisk, Z.*; Bauer, E. D.*
no journal, ,
To investigate the microscopic magnetism for -US, we have performed the nuclear magnetic resonance (NMR) experiments under high fields. Isotopic enrichment of S nuclei has been attempted to gain the NMR sensitivity. In this presentation, we will discuss about the relationship between the microscopic magnetism and electrical conductivity in -US.
S-NMR study in -USSakai, Hironori; Hattori, Taisuke; Higa, Nonoka; Tokunaga, Yo; Tateiwa, Naoyuki; Yamamoto, Etsuji; Haga, Yoshinori; Kambe, Shinsaku; Reyes, A. P.*; Bauer, E. D.*; et al.
no journal, ,
-US is a paramagnetic narrow-gap semiconductor with the energy band gap of 90 K. A characteristic feature of -US is the strong response of the electrical resistivity to magnetic field. On the other hand, ferromagnetism is easily induced by pressure of about 1 GPa. Consequently, it is considered to be close to a ferromagnetic instability. To elucidate microscopically this very sensitive electronic states to external fields, S-NMR study has been performed. We will show our recent S-NMR results and discuss the electronic states.
Sakai, Hironori; Tokunaga, Yo; Haga, Yoshinori; Kambe, Shinsaku; Zhu, J.-X.*; Ronning, F.*; Ramakrishna, S. K.*; Reyes, A. P.*; Kotegawa, Hisashi*; To, Hideki*; et al.
no journal, ,
In heavy fermion superconductor CeCoIn, slight Zn substitutions for In atoms induce antiferromagnetism, while slight Ni substitutions for Co atoms suppress superconductivity. The both substituted CeCoIn exhibit non- fermi-liquid behaviors near the phase boundaries which have been detected by magnetization and specific heat measurements. We have performed NMR experiments in these systems to investigate the microscopic effects by substituents. We will discuss about the spin fluctuations near the boundaries by NMR relaxation rates.
SiSakai, Hironori; Urbano, R. R.*; Tokunaga, Yo; Kambe, Shinsaku; Kuhns, P. L.*; Reyes, A. P.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*
no journal, ,
In order to microscopically investigate what happens around 22 T and just above 36 T in the lowest temperature, we have performed Si-NMR shift measurement using a Si-fully-enriched single crystal of URuSi. We have found a shift anomaly around 22 T and a critical increase toward 36 T, corresponding to a slight change of total density of states (DOS) at 22 T and increase of DOS toward 36 T. Although the Si-NMR signal was lost by field sweeping just above 36 T at the lowest temperature, the Si-NMR spectrum has been successfully obtained at 4.2 K in the magnetic phase just above 36 T. From the spectral shape, we will discuss a possible magnetic structure in the magnetic phase.
Si-NMR study of URuSiSakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Urbano, R. R.*; Kuhns, P. L.*; Reyes, A. P.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*
no journal, ,
The heavy fermion superconductor URuSi with 
K shows the "hidden order" at 
K. Below 1 K, it shows a first-order-transition at 
T from the hidden order phase to the magnetically ordered phase. The 
- phase diagram for URuSi above 35 T is known to be complicated but the details in the each phase above 35 T are unknown. We have been investigating the electronic state by means of Si-NMR in the higher field. The NMR experiment was done at National High Magnetic Field Laboratory (Tallahassee, FL, U.S.A.).
S NMR study in -USSakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Ramakrishna, S. K.*; Reyes, A. P.*; Rosa, P. F. S.*; Ronning, F.*; Thompson, J. D.*; Bauer, E. D.*
no journal, ,
Uranium disulfide -US is a paramagnetic semiconductor with a narrow band gap of 90 K at low temperatures, whereas above 80 K it is a semimetal with an extremely low density of carriers. Another characteristic feature in -US is the strong response of the electrical resistivity to magnetic field. The magnetoresistance is similar to that of colossal magnetoresistance materials but very anisotropic. In order to clarify the microscopic spin dynamics in -US, nuclear magnetic resonance experiments have been performed. Since the natural concentration of S nuclei (
) is only 0.76%, isotopic enrichment to 50% has been carried out. In the presentation, we would like to discuss about the microscopic magnetism in -US to show the NMR results under high fields.
