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Journal Articles

Sm valence determination of Sm-based intermetallics using $$^{149}$$Sm M$"{o}$ssbauer and Sm L$$_{rm III}$$-edge X-ray absorption spectroscopies

Tsutsui, Satoshi; Higashinaka, Ryuji*; Nakamura, Raito*; Fujiwara, Kosuke*; Nakamura, Jin*; Kobayashi, Yoshio*; Ito, Takashi; Yoda, Yoshitaka*; Kato, Kazuo*; Nitta, Kiyofumi*; et al.

Hyperfine Interactions, 242(1), p.32_1 - 32_10, 2021/12

Journal Articles

Highly-sensitive analysis of fluorescence XANES at Europium (Eu) L$$_{rm III}$$-edge for the determination of oxidation state for trace amount of Eu in natural samples by bragg-type crystal analyzer system

Konagaya, Rimi*; Kawamura, Naomi*; Yamaguchi, Akiko; Takahashi, Yoshio*

Chemistry Letters, 50(8), p.1570 - 1572, 2021/08

 Times Cited Count:1 Percentile:0(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

X-ray absorption spectroscopy in the heavy Fermion compound $$alpha$$-YbAlB$$_4$$ at high magnetic fields

Terashima, 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:3 Percentile:31.12(Physics, Multidisciplinary)

Journal Articles

Thermal expansion of a Au-Al-Yb intermediate valence quasicrystal

Watanuki, Tetsu; Kashimoto, Shiro*; Ishimasa, Tsutomu*; Machida, Akihiko; Yamamoto, Shin*; Tanaka, Yukinori*; Mizumaki, Masaichiro*; Kawamura, Naomi*; Watanabe, Shinji*

Solid State Communications, 211, p.19 - 22, 2015/06

 Times Cited Count:6 Percentile:31.61(Physics, Condensed Matter)

The thermal expansion of a Au-Al-Yb intermediate-valence quasicrystal has been studied by X-ray diffraction measurements. We have found anomalous thermal expansion behavior, namely zero thermal expansion below 50 K. By comparison with an isostructural Au-Al-Tm quasicrystal, the contribution of the Yb valence variation was extracted, and it was shown that its negative thermal expansion component due to the valence shift toward the divalent state by cooling compensated for the positive thermal expansion of the original lattice.

Journal Articles

Synchrotron X-ray spectroscopy study on the valence state and magnetization in $$alpha$$-YbAl$$_{1-x}$$Fe$$_x$$B$$_4$$ ($$x=0.115$$) at low temperatures and high magnetic fields

Terashima, 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:45.76

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 $$beta$$-YbAlB$$_4$$ 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 $$alpha$$-YbAl$$_{1-x}$$Fe$$_x$$B$$_4$$ ($$x=0.115$$), which is a locally isostructural polymorph of $$beta$$-YbAlB$$_4$$. 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.

Journal Articles

X-ray absorption spectroscopy and novel electronic properties in heavy fermion compounds YbT$$_{2}$$Zn$$_{20}$$ (T: Rh and Ir)

Honda, Fuminori*; Hirose, Yusuke*; Miyake, Atsushi*; Mizumaki, Masaichiro*; Kawamura, Naomi*; Tsutsui, Satoshi*; Watanuki, Tetsu; Watanabe, Shinji*; Takeuchi, Tetsuya*; Settai, Rikio*; et al.

Journal of Physics; Conference Series, 592(1), p.012021_1 - 012021_5, 2015/03

 Times Cited Count:2 Percentile:64.05

no abstracts in English

Journal Articles

Structure refinement for the $$alpha$$-$$varepsilon$$ transition of iron by using EXAFS

Ishimatsu, Naoki*; Sata,Yusuke*; Maruyama, Hiroshi*; Watanuki, Tetsu; Kawamura, Naomi*; Mizumaki, Masaichiro*; Irifune, Tetsuo*; Sumiya, Hitoshi*

Hoshako, 28(1), p.3 - 11, 2015/01

no abstracts in English

Journal Articles

Temperature and magnetic field dependent Yb valence in YbRh$$_2$$Si$$_2$$ observed by X-ray absorption spectroscopy

Nakai, 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:7 Percentile:50(Physics, Multidisciplinary)

The temperature and magnetic field dependences of Yb valence were observed in the heavy fermion compoundYbRh$$_2$$Si$$_2$$ 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, YbRh$$_2$$Si$$_2$$ 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.

Journal Articles

Synchrotron X-ray spectroscopy study on the valence state in $$alpha$$- and $$beta$$-TbAlB$$_4$$ at low temperature and high magnetic fields

Matsuda, 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:9 Percentile:56.19(Physics, Multidisciplinary)

The valence state of Yb ions in $$alpha$$- and $$beta$$-YbAlB$$_4$$ 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 ($$sim$$ 0.002) in $$beta$$-YbAlB$$_4$$ by a magnetic field of 32 T at 40 K.

Journal Articles

High-magnetic-field X-ray absorption and magnetic circular dichroism spectroscopy in the mixed-valent compound YbAgCu$$_4$$

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:59.76(Physics, Multidisciplinary)

The X-ray absorption and magnetic circular dichroism (MCD) spectra at the Yb L$$_3$$ edge were measured in the mixed-valent heavy fermion compound YbAgCu$$_4$$ 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$$^{3+}$$ state, while no feature is observed in the XMCD spectra corresponding to the Yb$$^{2+}$$ 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.

Journal Articles

Valence fluctuation in YbAgCu$$_4$$ at high Magnetic fields

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:10 Percentile:57.44(Physics, Multidisciplinary)

The valence change of Yb ion in YbAgCu$$_4$$ was measured by means of X-ray absorption spectroscopy under high magnetic fields up to 35T. The valence state of Yb in YbAgCu$$_4$$ at 4.8K significantly increases at the metamagnetic transition. The saturation value of $$v$$ at 55T is evaluated as 2.97 using the relation $$Delta M/Delta v$$ at 35T. This value is in good agreement with $$v$$ for the related compound YbInCu$$_4$$ at high temperatures and the Yb valence in the localized high-field phase. We conclude that the metamagnetic transition in YbAgCu$$_4$$ arises from the valence transition, as theoretically predicted.

Journal Articles

Orbital magnetism in Cd$$_2$$Os$$_2$$O$$_7$$ studied by X-ray magnetic circular dichroism

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:24 Percentile:66.92(Materials Science, Multidisciplinary)

X-ray magnetic circular dichroism (XMCD) at the $$L$$$$_{2,3}$$-edge of Os has been investigated in the antiferromagneticphase of Cd$$_2$$Os$$_2$$O$$_7$$, 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 ($$m_{rm L}$$) and spinmagnetic moment ($$m_{rm S}$$) is $$m_{rm L}/m_{rm S} = 0.16 pm 0.02$$, and that $$m_{rm L}$$ and $$m_{rm S}$$ are coupled in parallel ($$m_{rm L}parallel m_{rm S}$$). These phenomena are unusual in that the expected ground state of Os$$^{5+}$$ (5$$d^3$$) is an orbital singlet in a cubic crystal field, and $$m_{rm L}$$and $$m_{rm S}$$ 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.

Journal Articles

Colossal negative thermal expansion in BiNiO$$_{3}$$ induced by intermetallic charge transfer

Azuma, Masaki*; Chen, W.*; Seki, Hayato*; Czapski, M.*; Olga, S.*; Oka, Kengo*; Mizumaki, Masaichiro*; Watanuki, Tetsu; Ishimatsu, Naoki*; Kawamura, Naomi*; et al.

Nature Communications (Internet), 2, p.347_1 - 347_5, 2011/06

 Times Cited Count:307 Percentile:98.98(Multidisciplinary Sciences)

no abstracts in English

Journal Articles

XMCD spectroscopy on valence fluctuating and heavy fermion compounds in very high magnetic fields up to 40 T

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:86.22

Journal Articles

Effect of hydrogenation on the electronic state of metallic La hydrides probed by X-ray absorption sectroscopy at the La $$L$$-edges

Ishimatsu, Naoki*; Sasada, Ryohei*; Maruyama, Hiroshi*; Ichikawa, Takayuki*; Miyaoka, Hiroki*; Kimura, Toru*; Tsubota, Masami*; Kojima, Yoshitsugu*; Tsumuraya, Takao*; Oguchi, Tamio*; et al.

Journal of Physics; Conference Series, 190, p.012070_1 - 012070_4, 2009/11

 Times Cited Count:4 Percentile:76.95

We have investigated the effect of hydrogenation on La $$5d$$ and $$6p$$ electronic states in metallic LaH$$_x$$ by X-ray absorption near edge structure at the La $$L$$-edges. As the hydrogen content $$x$$ increases from 0 to 2.6, white-line intensity at the La $$L_{2,3}$$-edges shows a remarkable increase in the range of $$x$$ $$>$$ 2.0. This is interpreted as the increase in La $$5d$$ hole induced by interstitial H atoms on the octahedral sites. On the other hand, the shoulder structure at the La $$L_1$$-edge disappears in the process of $$x$$ = 0.0 $$rightarrow$$ 2.0, indicating that the $$p$$-$$ d$$ hybridization is weakened by H atoms on the tetrahedral sites. This study demonstrates that H atoms on the two interstitial H sites provide different contribution to the modification of the electronic states.

Journal Articles

Element and orbital-specific observation of two-step magnetic transition in NpNiGa$$_5$$; X-ray magnetic circular dichroism study

Okane, 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:30.75(Materials Science, Multidisciplinary)

Journal Articles

X-ray magnetic circular dichroism of a valence fluctuating state in Eu at high magnetic fields

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:50 Percentile:87.48(Physics, Multidisciplinary)

X-ray magnetic circular dichroism (XMCD) at the Eu L edge in two compounds exhibiting valence fluctuation, namely EuNi$$_2$$(Si$$_{0.18}$$Ge$$_{0.82}$$)$$_2$$ and EuNi$$_2$$P$$_2$$, has been investigated at high magnetic fields of up to 40T. A distinct XMCD peak corresponding to the trivalent state (Eu$$^{3+}$$), 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$$^{2+}$$). This result indicates that the 5$$d$$ electrons belonging to both valence states are magnetically polarized. It was also found that the ratio $$P$$$$_{5d}$$(3+)/$$P$$$$_{5d}$$(2+) between the polarization of 5$$d$$ electrons($$P$$$$_{5d}$$) in the Eu$$^{3+}$$ state and that of Eu$$^{2+}$$ depends on the material. The possible origin of the XMCD and an explanation of the material dependence of $$P$$$$_{5d}$$(3+)/$$P$$$$_{5d}$$(2+) are discussed in terms of hybridization between the conduction electrons and the f electrons.

Journal Articles

The H-Invitational Database (H-InvDB); A Comprehensive annotation resource for human genes and transcripts

Yamasaki, Chisato*; Murakami, Katsuhiko*; Fujii, Yasuyuki*; Sato, Yoshiharu*; Harada, Erimi*; Takeda, Junichi*; Taniya, Takayuki*; Sakate, Ryuichi*; Kikugawa, Shingo*; Shimada, Makoto*; et al.

Nucleic Acids Research, 36(Database), p.D793 - D799, 2008/01

 Times Cited Count:51 Percentile:73.57(Biochemistry & Molecular Biology)

Here we report the new features and improvements in our latest release of the H-Invitational Database, a comprehensive annotation resource for human genes and transcripts. H-InvDB, originally developed as an integrated database of the human transcriptome based on extensive annotation of large sets of fulllength cDNA (FLcDNA) clones, now provides annotation for 120 558 human mRNAs extracted from the International Nucleotide Sequence Databases (INSD), in addition to 54 978 human FLcDNAs, in the latest release H-InvDB. We mapped those human transcripts onto the human genome sequences (NCBI build 36.1) and determined 34 699 human gene clusters, which could define 34 057 protein-coding and 642 non-protein-coding loci; 858 transcribed loci overlapped with predicted pseudogenes.

Journal Articles

Magnetic and dielectric behavior of the ruthenium double perovskite oxides $$R$$$$_{2}$$$$M$$RuO$$_{6}$$ ($$R$$=La, Pr and Nd, $$M$$=Mg, Co, Ni and Zn)

Yoshii, Kenji; Ikeda, Naoshi*; Mori, Shigeo*; Yoneda, Yasuhiro; Mizumaki, Masaichiro*; Tanida, Hajime*; Kawamura, Naomi*

Transactions of the Materials Research Society of Japan, 32(1), p.51 - 54, 2007/03

Magnetic and dielectric properties of the ruthenium double perovskites $$R$$$$_{2}$$$$M$$RuO$$_{6}$$ were studied ($$M$$ = Co, Ni, Zn, Mg). The materials with the magnetic M$$^{2+}$$ ions ($$M$$ = Co and Ni) showed magnetic ordering and large dielectric constants (about 5000). On the other hand, for the non-magnetic M$$^{2+}$$ ions ($$M$$ = Mg and Zn), magnetic ordering was not observed. In addition, their dielectric constants were found to be small (about 100-200). Together with the result of the dielectric response, the large dielectric constants for $$M$$=Co and Ni may be related to a smooth response of polar regions. Investigations of the properties of $$R$$$$_{2}$$$$M$$RuO$$_{6}$$ with $$R$$=Pr and Nd are also being carried out, and their results are briefly discussed.

Journal Articles

Study on irradiation-induced magnetic transition in FeRh alloys by means of Fe K-edge XMCD spectroscopy

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:75.82(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.

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