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-YbAlB
at high magnetic fieldsTerashima, Taku*; Matsuda, Yasuhiro*; Kuga, Kentaro*; Suzuki, Shintaro*; Matsumoto, Yosuke*; Nakatsuji, Satoru*; Kondo, Akihiro*; Kindo, Koichi*; Kawamura, Naomi*; Mizumaki, Masaichiro*; et al.
Journal of the Physical Society of Japan, 84(11), p.114715_1 - 114715_4, 2015/11
Times Cited Count：4 Percentile：34.72(Physics, Multidisciplinary)
Sn cable assembled with conduit for ITER central solenoidNabara, Yoshihiro; Suwa, Tomone; Takahashi, Yoshikazu; Hemmi, Tsutomu; Kajitani, Hideki; Ozeki, Hidemasa; Sakurai, Takeru; Iguchi, Masahide; Nunoya, Yoshihiko; Isono, Takaaki; et al.
IEEE Transactions on Applied Superconductivity, 25(3), p.4200305_1 - 4200305_5, 2015/06
Times Cited Count：0 Percentile：0(Engineering, Electrical & Electronic)-YbAl
Fe
B (
) at low temperatures and high magnetic fieldsTerashima, Taku*; Matsuda, Yasuhiro*; Kuga, Kentaro*; Suzuki, Shintaro*; Matsumoto, Yosuke*; Nakatsuji, Satoru*; Kondo, Akihiro*; Kindo, Koichi*; Kawamura, Naomi*; Mizumaki, Masaichiro*; et al.
Journal of Physics; Conference Series, 592(1), p.012020_1 - 012020_6, 2015/03
Times Cited Count：1 Percentile：43.09(Physics, Atomic, Molecular & Chemical)Valence fluctuation phenomena in rare-earth intermetallic compounds have attracted attention because the quantum criticality of the valence transition has been proposed theoretically. Recently, it was found that 
-YbAlB shows quantum criticality without tuning and has a strong mixed-valence state. In this study, we measured the magnetization curve and X-ray magnetoabsorption in -YbAlFeB (), which is a locally isostructural polymorph of -YbAlB. The magnetization and X-ray experiments were performed in fields up to 55 and 40 T, respectively. A small increase in the Yb valence was observed at fields where the magnetization curve exhibited a change in slope.
Matsuda, Yasuhiro*; Her, J.-L.*; Michimura, Shinji*; Inami, Toshiya; Ebihara, Takao*; Amitsuka, Hiroshi*
JPS Conference Proceedings (Internet), 3, p.011044_1 - 011044_6, 2014/06
Synchrotron X-ray absorption spectroscopy of CeRh
Si has been performed in pulsed high magnetic fields of up to 32 T. The Ce valence is slightly larger than 3+ at 5 K and decreases with increasing magnetic above 20 T. The field-induced valence change seems to correspond to the metamagnetic transition in the magnetization process. This phenomena is similar to our previous result on CeRuSi and seems to be common in Ce-based heavy fermion compounds.
Si observed by X-ray absorption spectroscopyNakai, Hirohito*; Ebihara, Takao*; Tsutsui, Satoshi*; Mizumaki, Masaichiro*; Kawamura, Naomi*; Michimura, Shinji*; Inami, Toshiya; Nakamura, Toshiyuki*; Kondo, Akihiro*; Kindo, Koichi*; et al.
Journal of the Physical Society of Japan, 82(12), p.124712_1 - 124712_5, 2013/12
Times Cited Count：9 Percentile：53.5(Physics, Multidisciplinary)The temperature and magnetic field dependences of Yb valence were observed in the heavy fermion compoundYbRhSi by X-ray absorption spectroscopy. The measurements revealed that the Yb valence decreases with decreasing temperature in the range from 200 to 2 K and increases with increasing magnetic field in the range from 0 to 33 T without showing an abrupt change in the Yb valence. The Yb valence is in the range from 2.92 to 2.96 depending on temperature and magnetic field. With respect to the valence being 2.92 at 0 T and 2.93 at 33 T in 2 K, YbRhSi is a valence fluctuation compound and does not reach the integer trivalent state at high magnetic field. These results endorse the conventional knowledge that the valence of Yb is very close to the integer value of 3+, decreases with decreasing temperature, and becomes closer to 3+ with increasing magnetic field.
- and -TbAlB at low temperature and high magnetic fieldsMatsuda, Yasuhiro*; Nakamura, Toshiyuki*; Kuga, Kentaro*; Nakatsuji, Satoru*; Michimura, Shinji*; Inami, Toshiya; Kawamura, Naomi*; Mizumaki, Masaichiro*
Journal of the Korean Physical Society, 62(12), p.1778 - 1781, 2013/06
Times Cited Count：10 Percentile：55.85(Physics, Multidisciplinary)The valence state of Yb ions in - and -YbAlB has been investigated by X-ray absorption and emission spectroscopy at temperatures from 2 to 280 K. It is found that the valence gradually increases with increasing temperature toward 3+ and that the characteristic temperature of the valence fluctuations is about 290 K. We also observe a small increase in the Yb valence (
0.002) in -YbAlB by a magnetic field of 32 T at 40 K.
Matsuda, Yasuhiro*; Inami, Toshiya
Journal of the Physical Society of Japan, 82(2), p.021009_1 - 021009_17, 2013/02
Times Cited Count：7 Percentile：47.36(Physics, Multidisciplinary)Recent results of high-magnetic-field X-ray diffraction and absorption spectroscopy experiments using pulsed magnets are reviewed. Pulsed magnetic fields of up to 30-40 T are utilized. Structural changes induced by magnetic fields in rare-earth intermetallic compounds, transition-metal oxides and low-dimensional quantum spin compounds are presented as results of X-ray diffraction experiments. The structural changes are interpreted by several mechanisms. A magnetic X-ray scattering experiment has also been conducted at 30 T. Regarding X-ray absorption spectroscopy, the valence state transition in magnetic fields is observed in Yb-, Ce-, and Eu-based intermetallic compounds. Magnetic-field-induced changes in the structural and electronic states in transition-metal and rare-earth compounds were investigated using X-ray absorption spectra. The microscopic magnetic properties were examined by X-ray magnetic circular dichroism.
Nakamura, Toshiyuki*; Matsuda, Yasuhiro*; Her, J.-L.*; Kindo, Koichi*; Michimura, Shinji*; Inami, Toshiya; Mizumaki, Masaichiro*; Kawamura, Naomi*; Suzuki, Motohiro*; Chen, B.*; et al.
Journal of the Physical Society of Japan, 81(11), p.114702_1 - 114702_11, 2012/11
Times Cited Count：11 Percentile：57.45(Physics, Multidisciplinary)The X-ray absorption and magnetic circular dichroism (MCD) spectra at the Yb L
edge were measured in the mixed-valent heavy fermion compound YbAgCu at high magnetic fields and low temperatures. The magnetic-field-temperature (H-T) phase boundary determined by the valence state is in very good agreement with that determined by the magnetization. It is clearly found that the metamagnetism of this compound is due to the field induced valence transition. A distinctive positive peak of the XMCD spectra appears in the vicinity of the white line of the absorption due to Yb
state, while no feature is observed in the XMCD spectra corresponding to the Yb
state. A small negative XMCD peak was observed at a lower energy and was attributed to the quadrupole trasition from theoretical calcuration, which explains its peculicar magnetic field dependence.
-electron itinerancy in CeRuSi by a strong magnetic fieldMatsuda, Yasuhiro*; Nakamura, Toshiyuki*; Her, J. L.*; Michimura, Shinji*; Inami, Toshiya; Kindo, Koichi*; Ebihara, Takao*
Physical Review B, 86(4), p.041109_1 - 041109_4, 2012/07
Times Cited Count：9 Percentile：38.24(Materials Science, Multidisciplinary)The valence state of Ce in a typical heavy fermion compound CeRuSi has been investigated by synchrotron X-ray absorption spectroscopy at 1.8 K in high magnetic fields of up to 40T. The valence was slightly larger than for the pure trivalent state, as expected in heavy fermion compounds, and it decreased toward the trivalent state as the magnetic field was increased. The field-induced valence reduction indicates that the itinerant character of the 4 electrons in CeRuSi was suppressed by a strong magnetic field. The suppression was gradual and showed a characteristic magnetic field dependence, which reflects the metamagnetism around 
8T.
Hamada, Kazuya; Nunoya, Yoshihiko; Isono, Takaaki; Takahashi, Yoshikazu; Kawano, Katsumi; Saito, Toru; Oshikiri, Masayuki; Uno, Yasuhiro; Koizumi, Norikiyo; Nakajima, Hideo; et al.
IEEE Transactions on Applied Superconductivity, 22(3), p.4203404_1 - 4203404_4, 2012/06
Times Cited Count：17 Percentile：63.88(Engineering, Electrical & Electronic)Japan Atomic Energy Agency (JAEA) has the responsibility for procurement of all of the ITER central solenoid (CS) conductor lengths. The CS conductor is composed of 576 Nb Sn superconducting strands and 288 Cu strands assembled together into a multistage cable and protected by a circle-in-square sheath tube (jacket) with the outer dimension of 49 mm. In preparation for CS conductor production, the following R&D activities have been performed; (1) Mechanical tests at 4 K have been performed for jacket candidate materials such as 316LN and JK2LB, (2) Welding test for filler selection, (3) Measurement of coefficient of sliding friction using a 100-m long dummy cable, (4) Deformation characteristics of the conductor cross section after compaction and spooling. As a result of these R&D, the CS conductor jacket manufacturing technologies have been confirmed to start the procurement of the CS conductor.
at high Magnetic fieldsMatsuda, Yasuhiro*; Nakamura, Toshiyuki*; Her, J.-L.*; Kindo, Koichi*; Michimura, Shinji*; Inami, Toshiya; Mizumaki, Masaichiro*; Kawamura, Naomi*; Suzuki, Motohiro*; Chen, B.*; et al.
Journal of the Physical Society of Japan, 81(1), p.015002_1 - 015002_2, 2012/01
Times Cited Count：11 Percentile：57.45(Physics, Multidisciplinary)The valence change of Yb ion in YbAgCu was measured by means of X-ray absorption spectroscopy under high magnetic fields up to 35T. The valence state of Yb in YbAgCu at 4.8K significantly increases at the metamagnetic transition. The saturation value of 
at 55T is evaluated as 2.97 using the relation 
at 35T. This value is in good agreement with for the related compound YbInCu at high temperatures and the Yb valence in the localized high-field phase. We conclude that the metamagnetic transition in YbAgCu arises from the valence transition, as theoretically predicted.
OsO
studied by X-ray magnetic circular dichroismMatsuda, Yasuhiro*; Her, J.-L.*; Michimura, Shinji*; Inami, Toshiya; Suzuki, Motohiro*; Kawamura, Naomi*; Mizumaki, Masaichiro*; Kindo, Koichi*; Yamaura, Junichi*; Hiroi, Zenji*
Physical Review B, 84(17), p.174431_1 - 174431_5, 2011/11
Times Cited Count：25 Percentile：69.45(Materials Science, Multidisciplinary)X-ray magnetic circular dichroism (XMCD) at the 
-edge of Os has been investigated in the antiferromagneticphase of CdOsO, which exhibits a metal-insulator transition around 227 K. According to the sum rule, the XMCD spectra at 10 and 37 T clearly show that the ratio between the orbital magnetic moment (
) and spinmagnetic moment (
) is 
, and that and are coupled in parallel (
). These phenomena are unusual in that the expected ground state of Os
(5
) is an orbital singlet in a cubic crystal field, and and should be antiparallel for a less than half-filled system in accordance with Hund's third rule. It is likely that the spin-orbit coupling is important for explaining the observed orbital magnetism.
up to 30TInami, Toshiya; Owada, Kenji; Matsuda, Yasuhiro*; Ouyang, Z. W.*; Nojiri, Hiroyuki*; Matsumura, Takeshi*; Okuyama, Daisuke*; Murakami, Yoichi*
Journal of Physics; Conference Series, 211, p.012010_1 - 012010_6, 2010/02
Times Cited Count：3 Percentile：75.75(Physics, Applied)Matsuda, Yasuhiro*; Her, J. L.*; Inami, Toshiya; Owada, Kenji; Ouyang, Z. W.*; Okada, Kyoko*; Nojiri, Hiroyuki*; Mitsuda, Akihiro*; Wada, Hirofumi*; Yoshimura, Kazuyoshi*; et al.
Journal of Physics; Conference Series, 190, p.012019_1 - 012019_6, 2009/11
Times Cited Count：7 Percentile：85.12(Physics, Condensed Matter)Matsuda, Yasuhiro*; Ouyang, Z. W.*; Nojiri, Hiroyuki*; Inami, Toshiya; Owada, Kenji; Suzuki, Motohiro*; Kawamura, Naomi*; Mitsuda, Akihiro*; Wada, Hirofumi*
Physical Review Letters, 103(4), p.046402_1 - 046402_4, 2009/07
Times Cited Count：53 Percentile：87.05(Physics, Multidisciplinary)X-ray magnetic circular dichroism (XMCD) at the Eu L edge in two compounds exhibiting valence fluctuation, namely EuNi(Si
Ge
) and EuNiP, has been investigated at high magnetic fields of up to 40T. A distinct XMCD peak corresponding to the trivalent state (Eu), whose ground state is nonmagnetic (J = 0), was observed in addition to the main XMCD peak corresponding to the magnetic (J = 7/2) divalent state (Eu). This result indicates that the 5
electrons belonging to both valence states are magnetically polarized. It was also found that the ratio 
(3+)/(2+) between the polarization of 5 electrons() in the Eu state and that of Eu depends on the material. The possible origin of the XMCD and an explanation of the material dependence of (3+)/(2+) are discussed in terms of hybridization between the conduction electrons and the f electrons.
Inami, Toshiya; Owada, Kenji; Matsuda, Yasuhiro*; Ouyang, Z. W.*; Nojiri, Hiroyuki*; Matsumura, Takeshi*; Okuyama, Daisuke*; Murakami, Yoichi*
Journal of the Physical Society of Japan, 78(3), p.033707_1 - 033707_4, 2009/03
Times Cited Count：16 Percentile：65.71(Physics, Multidisciplinary)(SiGe)Matsuda, Yasuhiro*; Inami, Toshiya; Owada, Kenji; Murata, Yuto*; Nojiri, Hiroyuki*; Murakami, Yoichi*; Mitsuda, Akihiro*; Wada, Hirofumi*; Miyazaki, Hiroshi*; Harada, Isao*
Journal of the Physical Society of Japan, 77(5), p.054713_1 - 054713_7, 2008/05
Times Cited Count：25 Percentile：74.36(Physics, Multidisciplinary)The magnetic-field-induced valence transition in EuNi(SiGe) (x=0.82, 0.85) has been studied by X-ray absorption spectroscopy at low temperatures. The field dependence of the Eu valence is directly observed for the first time. We find a significant decrease in the valences at high magnetic fields above 40 T. The valence of Eu changes from v = 2.75 at a zero field to v = 2.33 at 40 T for x = 0.82. The results are analyzed using a theoretical model. The hybridization parameter V between the Eu and Eu states and the energy separation 
are determined, which are crucial for quantum mechanical mixing.
Pt using pulsed magnetic field X-ray diffractionOuyang, Z. W.*; Matsuda, Yasuhiro*; Nojiri, Hiroyuki*; Inami, Toshiya; Owada, Kenji; Tsubota, Masami*; Sakon, Takuo*; Fukuda, Takashi*; Kakeshita, Tomoyuki*
Journal of Applied Physics, 102(11), p.113917_1 - 113917_6, 2007/12
Times Cited Count：1 Percentile：5.41(Physics, Applied)Matsuda, Yasuhiro*; Inami, Toshiya; Owada, Kenji; Murata, Yuto*; Nojiri, Hiroyuki*; Murakami, Yoichi*; Ota, Hiroto*; Zhang, W.*; Yoshimura, Kazuyoshi*
Journal of the Physical Society of Japan, 76(3), p.034702_1 - 034702_6, 2007/03
Times Cited Count：56 Percentile：86.47(Physics, Multidisciplinary)no abstracts in English
Matsuda, Yasuhiro*; Inami, Toshiya; Owada, Kenji; Murata, Yuto*; Nojiri, Hiroyuki*; Murakami, Yoichi*; Ota, Hiroto*; Zhang, W.*; Yoshimura, Kazuyoshi*
Journal of the Physical Society of Japan, 75(2), p.024710_1 - 024710_5, 2006/02
Times Cited Count：39 Percentile：81.31(Physics, Multidisciplinary)We report the first high-field X-ray diffraction experiment using synchrotron X-rays and pulsedmagnetic fields exceeding 30 T. The lattice deformation due to a magnetic-field-induced valencetransition in YbInCu is studied. It has been found that the Bragg reflection profile at 32K changessignificantly at around 27 T due to the structural transition. In the vicinity of the transition field, the lowfield and high field phases alternate with the discontinuous change in the lattice constant. Thus, it isevident that the field-induced valence state transition is a first-order phase transition. The fielddependence of the low-field-phase Bragg peak intensity is found to be roughly scaled with themagnetization.
