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Zhang, A.*; Deng, K.*; Sheng, J.*; Liu, P.*; Kumar, S.*; Shimada, Kenya*; Jiang, Z.*; Liu, Z.*; Shen, D.*; Li, J.*; et al.
Chinese Physics Letters, 40(12), p.126101_1 - 126101_8, 2023/12
Times Cited Count：1 Percentile：0(Physics, Multidisciplinary)
Fe
intermetallic compoundCao, Y.*; Zhou, H.*; Khmelevskyi, S.*; Lin, K.*; Avdeev, M.*; Wang, C.-W.*; Wang, B.*; Hu, F.*; Kato, Kenichi*; Hattori, Takanori; et al.
Chemistry of Materials, 35(8), p.3249 - 3255, 2023/04
Times Cited Count：1 Percentile：0(Chemistry, Physical)Hydrostatic and chemical pressure are efficient stimuli to alter the crystal structure and are commonly used for tuning electronic and magnetic properties in materials science. However, chemical pressure is difficult to quantify and a clear correspondence between these two types of pressure is still lacking. Here, we study intermetallic candidates for a permanent magnet with a negative thermal expansion (NTE). Based on in situ synchrotron X-ray diffraction, negative chemical pressure is revealed in HoFe on Al doping and quantitatively evaluated by using temperature and pressure dependence of unit cell volume. A combination of magnetization and neutron diffraction measurements also allowed one to compare the effect of chemical pressure on magnetic ordering with that of hydrostatic pressure. Intriguingly, pressure can be used to control suppression and enhancement of NTE. Electronic structure calculations indicate that pressure affected the top of the majority band with respect to the Fermi level, which has implications for the magnetic stability, which in turn plays a critical role in modulating magnetism and NTE. This work presents a good example of understanding the effect of pressure and utilizing it to control properties of functional materials.
-Orbital component in the Borromean nucleus 
BYang, Z. H.*; Kubota, Yuki*; Corsi, A.*; Yoshida, Kazuki; Sun, X.-X.*; Li, J. G.*; Kimura, Masaaki*; Michel, N.*; Ogata, Kazuyuki*; Yuan, C. X.*; et al.
Physical Review Letters, 126(8), p.082501_1 - 082501_8, 2021/02
Times Cited Count：43 Percentile：96.7(Physics, Multidisciplinary)A quasifree (
,
) experiment was performed to study the structure of the Borromean nucleus B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for 
and 
orbitals, and a surprisingly small percentage of 9(2)% was determined for . Our finding of such a small component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in B. The present work gives the smallest - or -orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of or orbitals is not a prerequisite for the occurrence of a neutron halo.
Al-Shayeb, B.*; Sachdeva, R.*; Chen, L.-X.*; Ward, F.*; Munk, P.*; Devoto, A.*; Castelle, C. J.*; Olm, M. R.*; Bouma-Gregson, K.*; Amano, Yuki; et al.
Nature, 578(7795), p.425 - 431, 2020/02
Times Cited Count：220 Percentile：99.5(Multidisciplinary Sciences)
decay of 
USun, M. D.*; Liu, Z.*; Huang, T. H.*; Zhang, W. Q.*; Andreyev, A. N.; Ding, B.*; Wang, J. G.*; Liu, X. Y.*; Lu, H. Y.*; Hou, D. S.*; et al.
Physics Letters B, 800, p.135096_1 - 135096_5, 2020/01
Times Cited Count：11 Percentile：79.42(Astronomy & Astrophysics)
single unit-cell FeSe superconductorFukaya, Yuki; Zhou, G.*; Zheng, F.*; Zhang, P.*; Wang, L.*; Xue, Q.-K.*; Shamoto, Shinichi
Journal of Physics; Condensed Matter, 31(5), p.055701_1 - 055701_6, 2019/02
Times Cited Count：5 Percentile：27.39(Physics, Condensed Matter)no abstracts in English
Cr
NYabuuchi, Atsushi*; Maekawa, Masaki; Kawasuso, Atsuo; Zhou, Y.-K.*; Hasegawa, Shigehiko*; Asahi, Hajime*
Applied Physics Letters, 102(14), p.142406_1 - 142406_4, 2013/04
Times Cited Count：1 Percentile：4.63(Physics, Applied)
collisions at 
= 200 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review D, 84(1), p.012006_1 - 012006_18, 2011/07
Times Cited Count：29 Percentile：72.31(Astronomy & Astrophysics)We report on the event structure and double helicity asymmetry (
) of jet production in longitudinally polarized collisions at = 200 GeV. Photons and charged particles were measured by the PHENIX experiment. Event structure was compared with the results from PYTHIA event generator. The production rate of reconstructed jets is satisfactorily reproduced with the next-to-leading-order perturbative QCD calculation. We measured = -0.0014 
0.0037 at the lowest 
bin and -0.0181 0.0282 at the highest bin. The measured is compared with the predictions that assume various 
distributions.
collisions at = 200 and 62.4 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
Times Cited Count：184 Percentile：99.44(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
and Au+Au collisions at 
= 200 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.
Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04
Times Cited Count：8 Percentile：49.7(Physics, Nuclear)Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.
+ collisions at = 200 GeV and scaling properties of hadron productionAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review D, 83(5), p.052004_1 - 052004_26, 2011/03
Times Cited Count：175 Percentile：98.48(Astronomy & Astrophysics)The PHENIX experiment at RHIC has measured the invariant differential cross section for production of 
, 
, 
and 
mesons in collisions at = 200 GeV. The spectral shapes of all hadron transverse momentum distributions are well described by a Tsallis distribution functional form with only two parameters, 
and 
, determining the high 
and characterizing the low regions for the spectra, respectively. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.
Kawasuso, Atsuo; Yabuuchi, Atsushi; Maekawa, Masaki; Hasegawa, Shigehiko*; Zhou, Y.-K.*; Asahi, Hajime*
JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 148, 2011/01
Vacancy defects in GaCrN grown by molecular beam epitaxy have been characterized by energy variable positron beam. Both positron lifetime and the Doppler broadening of annihilation 
ray (DBAR) measurements show that the GaCrN film grown at low 540
C contains vacancy defects. The observed vacancy defects are identified as eight-vacancy clusters. Although the Si doping reduces such vacancy clusters probably due to the occupation of Ga sites, another type of vacancy defects still survives. From the detailed theoretical calculation, the residual vacancy defects are attributable to SiGa-VN complexes.
Yabuuchi, Atsushi; Maekawa, Masaki; Kawasuso, Atsuo; Hasegawa, Shigehiko*; Zhou, Y. K.*; Asahi, Hajime*
Journal of Physics; Conference Series, 262(1), p.012066_1 - 012066_4, 2011/01
Times Cited Count：0 Percentile：0.06(Physics, Applied)no abstracts in English
Chen, L.-M.; Kotaki, Hideyuki; Nakajima, Kazuhisa*; Koga, J. K.; Bulanov, S. V.; Tajima, Toshiki; Gu, Y. Q.*; Peng, H. S.*; Wang, X. X.*; Wen, T. S.*; et al.
Physics of Plasmas, 14(4), p.040703_1 - 040703_4, 2007/04
Times Cited Count：36 Percentile：75.52(Physics, Fluids & Plasmas)An experiment for the laser self-guiding studies has been carried out with 100 TW laser pulse interaction with the long underdense plasma. Formation of extremely long plasma channel with its length, about 10 mm, 20 times above the Rayleigh length is observed. The self-focusing channel features such as the laser pulse significant bending and the electron cavity formation are demonstrated experimentally for the first time.
Kawasuso, Atsuo; Yabuuchi, Atsushi; Maekawa, Masaki; Hasegawa, Shigehiko*; Zhou, Y.-K.*; Asahi, Hajime*
no journal, ,
no abstracts in English
Yabuuchi, Atsushi; Maekawa, Masaki; Kawasuso, Atsuo; Hasegawa, Shigehiko*; Zhou, Y.-K.*; Asahi, Hajime*
no journal, ,
The Doppler broadening of the positron annihilation radiation of the electron irradiated GaN sample was measured. The purpose of this study was to clarify the positron annihilation characteristics at point defects in GaN. 2 MeV electrons were irradiated to the MOCVD-GaN (2 
m)/Sapphire substrate with a total fluence of 6.5
10 e
/cm
at 60 C. The irradiated GaN was measured by using slow positron beam. As a result, the observed spectrum showed the existence of not monovacancies but vacancy clusters. This means vacancy clusters existed intrinsically in MOCVD-GaN film.
Yabuuchi, Atsushi; Maekawa, Masaki; Kawasuso, Atsuo; Hasegawa, Shigehiko*; Zhou, Y.-K.*; Asahi, Hajime*
no journal, ,
In the MBE growth of dilute magnetic semiconductors, the low-temperature growth has been attempted to suppress the precipitation of secondary phases. A current problem is a control of vacancy-type defects. Thus in this study, effects of growth conditions on formation of vacancy-type defects in MBE-grown GaN were investigated by positron annihilation spectroscopy. GaN buffer layers with the thickness of 30 nm were grown on sapphire substrates at 700C. Furthermore, GaN-cap (20 nm)/GaCrN (200 nm) layers were grown at different temperatures (540C, 300C and room temperature). For these samples, positron annihilation -ray peak intensity measurements were performed. As a result, the -ray peak intensity increased with decreasing the growth temperature. This result shows that the concentration or size of vacancy-type defects contained in the GaCrN layer increases with decreasing growth temperature.
ion implanted GaNYabuuchi, Atsushi; Maekawa, Masaki; Kawasuso, Atsuo; Hasegawa, Shigehiko*; Zhou, Y.-K.*; Asahi, Hajime*
no journal, ,
Recent GaN-based DMS studies have reported that Gd-doped GaN tend to indicate large magnetization in defective films. In addition, recent theoretical calculation study has also reported that a presence of vacancies affects the magnetic properties in DMS. In this study, Gd
ions were implanted into MOCVD-GaN film by using ion implantation techniques. Furthermore, we have attempted to clarify the correlation between the magnetic properties and presence of vacancy-type defects. As a result, irradiation-induced defects have decreased greatly at 1000 C annealing. However, vacancy-type defects were still remained after 1300 C annealing. Alternating gradient magnetometer (AGM) measurements were also performed at room temperature for the unimplanted, as-implanted and post-implanted 1300 C annealed GaN films. However, clear magnetic hystereses were not observed even in the as-implanted film. In further study, high temperature ion implantation experiments are needed.
Maekawa, Masaki; Zhou, K.*; Fukaya, Yuki; Zhang, H.; Li, H.; Kawasuso, Atsuo
no journal, ,
no abstracts in English
Maekawa, Masaki; Zhou, K.*; Fukaya, Yuki; Zhang, H.; Li, H.; Kawasuso, Atsuo
no journal, ,
no abstracts in English
