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Ni
In
Sakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Zhu, J.-X.*; Ronning, F.*; Thompson, J. D.*; Kotegawa, Hisashi*; To, Hideki*; Suzuki, Kohei*; Oshima, Yoshiki*; et al.
Physical Review B, 106(23), p.235152_1 - 235152_8, 2022/12
Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)We investigate the electronic state of Ni-substituted CeCoNi
In by nuclear quadrupole and magnetic resonance (NQR/NMR) techniques. The heavy fermion superconductivity below 
K for 
is suppressed by Ni substitutions, and 
reaches zero for 
. The 
In NQR spectra for 
and 0.25 can be explained by simulating the electrical field gradient that is calculated for a virtual supercell with density functional theory. The spin-lattice relaxation rate 
indicates that Ni substitution weakens antiferromagnetic correlations that are not localized near the substituent but instead are uniform in space. The temperature (
) dependence of 
for shows a maximum around 
K and decreases toward almost zero when temperature is further reduced as if a gap might be opening in the magnetic excitation spectrum; however, the magnetic specific heat and the static magnetic susceptibility evolve smoothly through 
with a 
dependence. The peculiar T dependence of and non-Fermi-liquid specific heat and susceptibility can be interpreted in a unified way by assuming nested antiferromagnetic spin fluctuations in a quasi-two-dimensional electronic system.
; 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：3 Percentile：27.71(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.
Pu nuclear magnetic resonance in the candidate topological insulator PuB
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：8 Percentile：37.59(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.
; NQR relaxation ratesSakai, Hironori; Ronning, F.*; Hattori, Takanori; Tokunaga, Yo; Kambe, Shinsaku; Zhu, J.-X.*; Wakeham, N.*; Yasuoka, Hiroshi; Bauer, E. D.*; Thompson, J. D.*
Journal of Physics; Conference Series, 807(3), p.032001_1 - 032001_6, 2017/04
Times Cited Count：3 Percentile：68.62(Physics, Condensed Matter)We have used nuclear quadrupole resonance (NQR) to probe microscopically the response of a prototypical quantum critical metal CeCoIn to substitutions of small amounts of Cd for In. Approximately half of the Cd substituents induce local Ce moments in their close proximity, as observed by site-dependent longitudinal nuclear spin relaxation rates . To reaffirm that localized 
moments are induced around the Cd substituents, we find a Gaussian spin-echo decay rate 
of transverse nuclear spin relaxation. Further, 
for the NQR subpeak is found to be proportional to temperatures, again indicating local moments fluctuations around the Cd substituents, while that for the NQR main peak shows a 
-dependence. The latter temperature dependence is close to 0.75 in pure CeCoIn and indicates that the bulk electronic state is located close to a two dimensional quantum critical instability.
Te
Ye, M.*; Li, W.*; Zhu, S.-Y.*; Takeda, Yukiharu; Saito, Yuji; Wang, J.*; Pan, H.*; Nurmamat, M.*; Sumida, Kazuki*; Ji, F.*; et al.
Nature Communications (Internet), 6, p.8913_1 - 8913_7, 2015/11
Times Cited Count：52 Percentile：89.95(Multidisciplinary Sciences)Magnetically doped topological insulators are predicted to exhibit exotic phenomena including the quantized anomalous Hall effect and a dissipationless transport, which facilitate the development of low-power-consumption devices using electron spins. The realization of the quantized anomalous Hall effect is so far restricted to the Cr-doped (Sb,Bi)Te system at extremely low temperature; however, the microscopic origin of its ferromagnetism is poorly understood. Here we present an element-resolved study for Cr-doped (Sb,Bi)Te using X-ray magnetic circular dichroism to unambiguously show that the long-range magnetic order is mediated by the p-hole carriers of the host lattice, and the interaction between the Sb(Te) p and Cr d states is crucial.
Sakai, Hironori; Ronning, F.*; Zhu, J.-X.*; Wakeham, N.*; Yasuoka, Hiroshi; Tokunaga, Yo; Kambe, Shinsaku; Bauer, E. D.*; Thompson, J. D.*
Physical Review B, 92(12), p.121105_1 - 121105_5, 2015/09
Times Cited Count：19 Percentile：62.1(Materials Science, Multidisciplinary)Chemical substitutions are used commonly to tune a magnetic transition to zero temperature, but the resulting non-Fermi liquid (NFL) behavior is non-universal. We have used nuclear quadrupole resonance (NQR) to probe microscopically the response of a prototypical quantum-critical metal CeCoIn to substitutions of small amounts of Sn and Cd for In. These substituents induce very different local electronic environments as observed by site dependent spin lattice relaxation rates that influence the NFL behavior. The effects found here illustrate the need for care in interpreting NFL properties determined by macroscopic measurements.
Pace, D. C.*; Austin, M. E.*; Bass, E. M.*; Budny, R.*; Heidbrink, W. W.*; Hillesheim, J. C.*; Holcomb, C. T.*; Gorelenkova, M.*; Grierson, B. A.*; McCune, D. C.*; et al.
Physics of Plasmas, 20(5), p.056108_1 - 056108_18, 2013/05
Times Cited Count：33 Percentile：82.22(Physics, Fluids & Plasmas)Energetic ion transport due to microturbulence is investigated in MHD-quiescent plasmas by way of neutral beam injection in the DIII-D tokamak. A range of on-axis and off-axis beam injection scenarios are employed to vary relevant parameters such as the character of the background microturbulence and the value of Eb/Te, where Eb is the energetic ion energy and Te the electron temperature. In all cases it is found that any transport enhancement due to microturbulence is too small to observe experimentally. These transport effects are modeled using numerical and analytic expectations that calculate the energetic ion diffusivity due to microturbulence. It is determined that energetic ion transport due to coherent modes, including possible reductions in neutral beam current drive, is a considerably larger effect and should therefore be considered more important for ITER.
PBender, P. C.*; Tabor, S. L.*; Tripathi, V.*; Hoffman, C. R.*; Hamilton, L.*; Volya, A.*; Clark, R. M.*; Fallon, P.*; Macchiavelli, A. O.*; Paschalis, S.*; et al.
Physical Review C, 85(4), p.044305_1 - 044305_10, 2012/04
Times Cited Count：12 Percentile：56.39(Physics, Nuclear)The available experimental information on P has been greatly increased through the analysis of 
decays in coincidence with protons from the interaction of an 
O beam at 24 MeV with an O target. Light charged particles from the reaction were detected with Microball, and multiple ray coincidences with Gammasphere. Many newly observed transitions have been identified and placed in the level scheme. Additionally, for most states, spins have been assigned based on measured ray angular distributions while parities were inferred from lifetimes determined through Doppler-broadened line-shape analysis. Most of the states observed have been interpreted in terms of shell-model calculations using the WBP-a and SDPF-NR interactions having one particle in the 0
or 1
orbital. The two calculations agree almost equally well with the data resulting in root-mean-square differences of about 200 keV. However, two of a few high-lying states may be associated with stretched 
states, but the calculations over-predict their energies by 2-3 MeV. Furthermore, a newly observed long-lived 7919-keV state is established for which no explanation is available at present.
Schaffer, M. J.*; Snipes, J. A.*; Gohil, P.*; de Vries, P.*; Evans, T. E.*; Fenstermacher, M. E.*; Gao, X.*; Garofalo, A. M.*; Gates, D. A.*; Greenfield, C. M.*; et al.
Nuclear Fusion, 51(10), p.103028_1 - 103028_11, 2011/10
Times Cited Count：35 Percentile：80.59(Physics, Fluids & Plasmas)Experiments at DIII-D investigated the effects of ferromagnetic error fields similar to those expected from proposed ITER Test Blanket Modules (TBMs). Studied were effects on: plasma rotation and locking; confinement; L-H transition; edge localized mode (ELM) suppression by resonant magnetic perturbations; ELMs and the H-mode pedestal; energetic particle losses; and more. The experiments used a 3-coil mock-up of 2 magnetized ITER TBMs in one ITER equatorial port. The experiments did not reveal any effect likely to preclude ITER operations with a TBM-like error field. The largest effect was slowed plasma toroidal rotation v across the entire radial profile by as much as 
via non-resonant braking. Changes to global 
, 
and 
were 
3 times smaller. These effects are stronger at higher 
and lower 
. Other effects were smaller.
Deng, Z.*; Jin, C. Q.*; Liu, Q. Q.*; Wang, X. C.*; Zhu, J. L.*; Feng, S. M.*; Chen, L. C.*; Yu, R. C.*; Arguello, C.*; Goko, Tatsuo*; et al.
Nature Communications (Internet), 2, p.1425_1 - 1425_5, 2011/08
Times Cited Count：158 Percentile：93.74(Multidisciplinary Sciences)In a prototypical ferromagnet (Ga,Mn)As based on a III-V semiconductor, substitution of divalent Mn atoms into trivalent Ga sites leads to severely limited chemical solubility and metastable specimens available only as thin films. The doping of hole carriers via (Ga,Mn) substitution also prohibits electron doping. To overcome these difficulties, Masek et al. theoretically proposed systems based on a I-II-V semiconductor LiZnAs, where isovalent (Zn,Mn) substitution is decoupled from carrier doping with excess/deficient Li concentrations. Here we show successful synthesis of Li
(ZnMn)As in bulk materials. We reported that ferromagnetism with a critical temperature of up to 50 K is observed in nominally Li-excess compounds, which have p-type carriers.
isomer in 
RfRobinson, A. P.*; Khoo, T. L.*; Seweryniak, D.*; Ahmad, I.*; Asai, Masato; Back, B. B.*; Carpenter, M. P.*; Chowdhury, P.*; Davids, C. N.*; Greene, J.*; et al.
Physical Review C, 83(6), p.064311_1 - 064311_7, 2011/06
Times Cited Count：32 Percentile：84.86(Physics, Nuclear)We have identified an isomer with a half-life of 17 
s in Rf through a calorimetric conversion electron measurement tagged with implanted Rf nuclei using the fragment mass analyzer at Argonne National Laboratory. The low population yield for this isomer suggests that this isomer should not be a 2-quasiparticle high- isomer which is typically observed in the N = 152 isotones, but should be a 4-quasiparticle one. Possible reasons of the non-observation of a 2-quasiparticle isomer are this isomer decays by fission with a half-life similar to that of the ground state of Rf. Another possibility, that there is no 2-quasiparticle isomer at all, would imply an abrupt termination of axially symmetric deformed shape at Z=104.
Seweryniak, D.*; Khoo, T. L.*; Ahmad, I.*; Kondev, F. G.*; Robinson, A.*; Tandel, S. K.*; Asai, Masato; Back, B. B.*; Carpenter, M. P.*; Chowdhury, P.*; et al.
Nuclear Physics A, 834(1-4), p.357c - 361c, 2010/03
Times Cited Count：7 Percentile：47.82(Physics, Nuclear)Experimental data on single-particle energies in nuclei around Z=100 and N=152 play an important role to test validity of theoretical predictions for shell structure of superheavy nuclei. We found high-K two-quasiparticle isomers in 
No and 
No, and evaluated energies of proton single-particle orbitals around Z=100. We also found a new high-K three quasiparticle isomer in 
Rf. Energies of neutron single-particle orbitals were also evaluated from experimental data of the 
decay of Rf. Comparisons between the present experimental data and various theoretical calculations for the proton single-particle orbitals indicate that the calculation by using the Woods-Saxon potential gives the best agreement with the data.
RfQian, J.*; Heinz, A.*; Khoo, T. L.*; Janssens, R. V. F.*; Peterson, D.*; Seweryniak, D.*; Ahmad, I.*; Asai, Masato; Back, B. B.*; Carpenter, M. P.*; et al.
Physical Review C, 79(6), p.064319_1 - 064319_13, 2009/06
Times Cited Count：31 Percentile：83.95(Physics, Nuclear)-, -, and conversion electron spectroscopy experiments for Rf have been performed using Fragment Mass Analyzer at Argonne National Laboratory. A new isomer with a half-life of 160 s has been discovered in Rf, and it is interpreted as a three-quasiparticle high- isomer. Neutron configurations of one-quasiparticle states in 
No, the -decay daughter of Rf, have been assigned on the basis of -decay hindrance factors. Excitation energies of the 1/2
[620] states in 
=151 isotones indicate that the deformed shell gap at =152 increases with the atomic number.
isomers and 
octupole vibrations in 
shell-stabilized isotonesRobinson, A. P.*; Khoo, T. L.*; Ahmad, I.*; Tandel, S. K.*; Kondev, F. G.*; Nakatsukasa, Takashi*; Seweryniak, D.*; Asai, Masato; Back, B. B.*; Carpenter, M. P.*; et al.
Physical Review C, 78(3), p.034308_1 - 034308_6, 2008/09
Times Cited Count：49 Percentile：90.87(Physics, Nuclear)Isomers have been identified in 
Cm and No with quantum number , which decay through rotational bands built on octupole vibrational states. For isotones with atomic number 
102, the and 2
states have remarkably stable energies, indicating neutron excitations. An exception is a singular minimum in the 2 energy at Cm, due to the additional role of proton configurations.
PWiedeking, M.*; Rodriguez-Vieitez, E.*; Fallon, P.*; Carpenter, M. P.*; Clark, R. M.*; Cline, D.*; Cromaz, M.*; Descovich, M.*; Janssens, R. V. F.*; Lee, I.-Y.*; et al.
Physical Review C, 78(3), p.037302_1 - 037302_4, 2008/09
Times Cited Count：14 Percentile：64.91(Physics, Nuclear)no abstracts in English
probed by muon spin rotationOishi, Kazuki; Heffner, R. H.; Ito, Takashi; Higemoto, Wataru; Morris, G. D.*; Bauer, E. D.*; Graf, M. J.*; Zhu, J.-X.*; Morales, L. A.*; Sarrao, J. L.*; et al.
Physica B; Condensed Matter, 403(5-9), p.1013 - 1014, 2008/04
Times Cited Count：0 Percentile：0(Physics, Condensed Matter)PuCoGa has attracted much interest because it is the first Pu-based superconductor, having an order of magnitude higher transition temperature 
K than the isostructural heavy fermion superconductor CeCoIn (
K). The mechanism of the superconductivity in PuCoGa is still under investigation, though recent experiments and theory suggest a magnetic origin. A unique aspect of this compound is the self-irradiation damage because Pu (Pu, 
= 24,000 years) creates lattice defects which scatter electrons and, hence, break superconducting pairs. In order to elucidate the magnitude and temperature dependence of the magnetic penetration depth 
, we have performed SR measurements in the same PuCoGa single crystals after 25 and 400 days of aging. We found that decreased from 18.5K to 15K for the aged sample, yet a quasi-linear temperature dependence was found for the low-temperature 
in both the fresh and aged sample, consistent with 
-wave pairing symmetry. The magnitude of the muon spin relaxation rate 
in the aged sample, 
, where 
and 
are the superfluid density and the effective mass, respectively, is reduced by about 70% compared to fresh sample. This indicates that the scattering from self-irradiation induced defects is not in the limit of the conventional Abrikosov-Gor'kov pair-breaking theory, but rather in the limit of short coherence length (about 2nm in PuCoGa) superconductivity.
Oishi, Kazuki; Heffner, R. H.; Morris, G. D.*; Bauer, E. D.*; Graf, M. J.*; Zhu, J.-X.*; Morales, L. A.*; Sarrao, J. L.*; Fluss, M. J.*; MacLaughlin, D. E.*; et al.
Physical Review B, 76(6), p.064504_1 - 064504_10, 2007/08
Times Cited Count：13 Percentile：51.77(Materials Science, Multidisciplinary)Zhu, X. D.*; Narumi, Kazumasa; Naramoto, Hiroshi*
Journal of Physics; Condensed Matter, 19(23), p.236227_1 - 236227_6, 2007/06
Times Cited Count：6 Percentile：31.31(Physics, Condensed Matter)In this paper, we report the buckling instability in amorphous carbon films on mirror-polished sapphire (0001) wafers deposited by ion beam assisted deposition at various growth temperatures. For the films deposited at 150
C, many interesting stress relief patterns are found, which include networks, blisters, sinusoidal patterns with -shape, and highly ordered sinusoidal waves on a large scale. Starting at irregular buckling in the centre, the latter propagate towards the outer buckling region. The maximum length of these ordered patterns reaches 396 m with a height of 500 nm and a wavelength of 8.2 m. However, the length decreases dramatically to 70 m as the deposition temperature is increased to 550C. The delamination of the film appears instead of sinusoidal waves with a further increase of the deposition temperature. This experimental observation is correlated with the theoretic work of Crosby (1999 Phys. Rev. E 59 R2542).
Lipschultz, B.*; Asakura, Nobuyuki; Bonnin, X.*; Coster, D. P.*; Counsell, G.*; Doerner, R.*; Dux, R.*; Federici, G.*; Fenstermacher, M. E.*; Fundamenski, W.*; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
The work of the ITPA SOL/divertor group is reviewed. The high-n nature of ELMs has been elucidated and new measurements have determined that they carry 10-20% of the ELM energy to the far SOL with implications for ITER limiters and the upper divertor. Analysis of ELM measurements imply that the ELM continuously loses energy as it travels across the SOL. The prediction of ITER divertor disruption power loads have been reduced as a result of finding that the divertor footprint broadens during the thermal quench and that the plasma can lose up to 80% of its thermal energy before the thermal quench (not for VDEs or ITBs). Disruption mitigation through massive gas puffing has been successful at reducing divertor heat loads but estimates of the effect on the main chamber walls indicate 10s of kG of Be would be melted/mitigation. Long-pulse studies have shown that the fraction of injected gas that can be recovered after a discharge decreases with discharge length. The use of mixed materials gives rise to a number of potential processes.
Zhu, X. D.*; Ding, F.*; Naramoto, Hiroshi*; Narumi, Kazumasa
Applied Surface Science, 253(3), p.1480 - 1483, 2006/11
Times Cited Count：8 Percentile：38.44(Chemistry, Physical)Hydrogen-free amorphous carbons (a-C) have been prepared on mirror-polished Si(111) wafers through thermally evaporated C
with simultaneous bombardments of Ne ions. The time evolution of film surfaces has been characterized by atomic force microscopy (AFM) at two temperatures of 400 and 700 C. Based on the topography images and the root-mean-square (rms) roughness analysis, it is found that the a-C surfaces present roughening growth at the initial stage. With increasing growth time, the cooperative nucleation of the islands and pits appears on the surfaces, suggesting three-dimensional growth, and then they continue to evolve to irregular mounds at 400 C, and elongated mounds at 700 C. At the steady growth stage, these surfaces further develop to the structures of bamboo joints and ripples corresponding to these two temperatures, respectively. It is believed that besides ion sputtering effect, the chemical bonding configurations in the amorphous carbon films should be taken into considerations for elucidating the surface evolutions.
