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Kikkawa, Takashi*; Suzuki, Motohiro*; Ramos, R.*; Aguirre, M. H.*; Okabayashi, Jun*; Uchida, Kenichi*; Lucas, I.*; Anadn, A.*; Kikuchi, Daisuke*; Algarabel, P. A.*; et al.
Journal of Applied Physics, 126(14), p.143903_1 - 143903_11, 2019/10
Times Cited Count:9 Percentile:49.38(Physics, Applied)Kikkawa, Takashi*; Suzuki, Motohiro*; Okabayashi, Jun*; Uchida, Kenichi*; Kikuchi, Daisuke*; Qiu, Z.*; Saito, Eiji
Physical Review B, 95(21), p.214416_1 - 214416_7, 2017/06
Times Cited Count:15 Percentile:60.18(Materials Science, Multidisciplinary)Hu, W.*; Hayashi, Koichi*; Fukumura, Tomoteru*; Akagi, Kazuto*; Tsukada, Masaru*; Happo, Naohisa*; Hosokawa, Shinya*; Owada, Kenji; Takahashi, Masamitsu; Suzuki, Motohiro*; et al.
Applied Physics Letters, 106(22), p.222403_1 - 222403_5, 2015/06
Times Cited Count:39 Percentile:82.42(Physics, Applied)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:58.12(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.
Matsuda, 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:58.12(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.
Matsuda, 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:70.18(Materials Science, Multidisciplinary)X-ray magnetic circular dichroism (XMCD) at the -edge of Os has been investigated in the antiferromagneticphase of Cd
Os
O
, 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.
Happo, Naohisa*; Tekehara, Yuki*; Fujiwara, Makoto*; Tanaka, Koichi*; Semba, Shinya*; Hosokawa, Shinya*; Hayashi, Koichi*; Hu, W.; Suzuki, Motohiro*; Asada, Hironori*
e-Journal of Surface Science and Nanotechnology (Internet), 9, p.247 - 250, 2011/06
Happo, Naohisa*; Tekehara, Yuki*; Fujiwara, Makoto*; Tanaka, Koichi*; Semba, Shinya*; Hosokawa, Shinya*; Hayashi, Koichi*; Hu, W.; Suzuki, Motohiro*; Asada, Hironori*
Japanese Journal of Applied Physics, 50(5), p.05FC11_1 - 05FC11_2, 2011/05
Times Cited Count:5 Percentile:23.79(Physics, Applied)Hayashi, Koichi*; Uchitomi, Naotaka*; Asubar, J. T.*; Happo, Naohisa*; Hu, W.; Hosokawa, Shinya*; Suzuki, Motohiro*
Japanese Journal of Applied Physics, 50(1), p.01BF05_1 - 01BF05_4, 2011/01
Times Cited Count:1 Percentile:4.89(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:85.61Okane, Tetsuo; Okochi, Takuo*; Inami, Toshiya; Takeda, Yukiharu; Fujimori, Shinichi; Kawamura, Naomi*; Suzuki, Motohiro*; Tsutsui, Satoshi*; Yamagami, Hiroshi; Fujimori, Atsushi; et al.
Physical Review B, 80(10), p.104419_1 - 104419_7, 2009/09
Times Cited Count:6 Percentile:29.78(Materials Science, Multidisciplinary)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:87.43(Physics, Multidisciplinary)X-ray magnetic circular dichroism (XMCD) at the Eu L edge in two compounds exhibiting valence fluctuation, namely EuNi(Si
Ge
)
and EuNi
P
, 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.
Kobayashi, Yasuhiko; Funayama, Tomoo; Hamada, Nobuyuki*; Sakashita, Tetsuya; Konishi, Teruaki*; Imaseki, Hitoshi*; Yasuda, Keisuke*; Hatashita, Masanori*; Takagi, Keiichi*; Hatori, Satoshi*; et al.
Journal of Radiation Research, 50(Suppl.A), p.A29 - A47, 2009/03
Times Cited Count:37 Percentile:72.51(Biology)Iwase, Akihiro*; Fukuzumi, Masafumi*; Zushi, Yoshihiro*; Suzuki, Motohiro*; Takagaki, Masafumi*; Kawamura, Naomi*; Chimi, Yasuhiro; Mizuki, Junichiro; Ishikawa, Norito; Ono, Fumihisa*
Nuclear Instruments and Methods in Physics Research B, 256(1), p.429 - 433, 2007/01
Times Cited Count:17 Percentile:74.23(Instruments & Instrumentation)We have studied the effects of swift heavy ion irradiation on the magnetic properties of Fe-Rh intermetallic compound by using Fe K-edge X-ray magnetic circular dichroism (XMCD) at 20 K. For an unirrdaiated specimen, no signal of XMCD spectrum has been observed because Fe-Rh intermetallic compound is intrinsically anti-ferromagnetic below room temperature. For the specimens irradiated with 120-200 MeV Ni, Kr, Xe or Au ions, we have found XMCD spectra which are characterized by a dispersion-type profile with a positive peak and a negative peak near Fe K-edge. The intensity of XMCD spectra remarkably depends on ion-fluence and ion-mass. The experimental result implies that the ferromagnetic state is induced by the swift heavy ion irradiation. The change in magnetic state of Fe element is discussed in terms of energy deposition through the elastic and electronic processes.
Fukuzumi, Masafumi*; Chimi, Yasuhiro; Ishikawa, Norito; Suzuki, Motohiro*; Takagaki, Masafumi*; Mizuki, Junichiro; Ono, Fumihisa*; Neumann, R.*; Iwase, Akihiro*
Nuclear Instruments and Methods in Physics Research B, 245(1), p.161 - 165, 2006/04
Times Cited Count:17 Percentile:75.02(Instruments & Instrumentation)We have performed swift heavy ion irradiations in Fe-50at.%Rh alloys at room temperature. Before and after the irradiations, the magnetic properties and the lattice structure are measured using Superconducting QUantum Interference Device (SQUID) and X-Ray Diffractometer (XRD), respectively. We have also performed X-ray Magnetic Circular Dichroism (XMCD) measurement near the Fe K-edge at the synchrotron radiation facility, SPring-8, to examine the irradiation-induced ferromagnetic state near the specimen surface. We have found that the swift heavy ion irradiations induce the ferromagnetic state in Fe-50at.%Rh alloy below the antiferromagnetism-ferromagnetism transition temperature of the unirradiated alloy and the lattice expasion by 0.3%. For the specimens irradiated with swift heavy ions, we observe the XMCD spectra correponding to ferromagnetisim, which depend on the mass of irradiating ions and/or irradiation fluence. Effects of energy loss through electronic excitation and elastic collisions on lattice and magnetic structures of Fe-Rh alloy are discussed.
Okane, Tetsuo; Okochi, Takuo; Takeda, Yukiharu; Fujimori, Shinichi; Saito, Yuji; Yamagami, Hiroshi; Fujimori, Atsushi*; Kawamura, Naomi*; Suzuki, Motohiro*; Tsutsui, Satoshi*; et al.
no journal, ,
no abstracts in English
Ishikawa, Norito; Kawasuso, Atsuo; Takagaki, Masafumi*; Suzuki, Motohiro*; Mizuki, Junichiro; Zushi, Yoshihiro*; Fujita, Naoki*; Hori, Fuminobu*; Seki, Shuhei*; Tsukuda, Satoshi*; et al.
no journal, ,
It is already found that magnetic transition temperature of Fe-50at.%Rh changes by high-energy ion irradiation. This irradiation-induced changes in magnetic properties has been investigated by magnetic force microscopy. It has been found that microscopic magnetic structure appears after ion-irradiation, and the structure changes depending on the ion-fluence. The observed structure was not the same as that observed for Fe-rich ferromagnetic Fe-45at.%Rh alloys.