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Kaneko, Koji; Cheung, Y. W.*; Hu, Y.*; Imai, Masaki*; Tanioku, Yasuaki*; Kanagawa, Hibiki*; Murakawa, Joichi*; Moriyama, Kodai*; Zhang, W.*; Lai, K. T.*; et al.
JPS Conference Proceedings (Internet), 30, p.011032_1 - 011032_6, 2020/03
Cheung, Y. W.*; Hu, Y. J.*; Imai, Masaki*; Tanioku, Yasuaki*; Kanagawa, Hibiki*; Murakawa, Joichi*; Moriyama, Kodai*; Zhang, W.*; Lai, K. T.*; Yoshimura, Kazuyoshi*; et al.
Physical Review B, 98(16), p.161103_1 - 161103_5, 2018/10
Times Cited Count:20 Percentile:65.12(Materials Science, Multidisciplinary)Sakai, Hironori; Hattori, Taisuke; Tokunaga, Yo; Kambe, Shinsaku; Ueda, Hiroaki*; Tanioku, Yasuaki*; Michioka, Chishiro*; Yoshimura, Kazuyoshi*; Takao, Kenta*; Shimoda, Aiko*; et al.
Physical Review B, 98(6), p.064403_1 - 064403_10, 2018/08
Times Cited Count:15 Percentile:55.70(Materials Science, Multidisciplinary)To specify preferential occupation sites of Co substituents and to clarify charge and spin states of Co ions in (La, Co)-cosubstituted hexagonal magnetoplumbite-type (M-type) Sr ferrite, Fe and
Co nuclear magnetic resonance (NMR) spectra are measured under zero and external magnetic fields using powdered and single crystalline specimens. To a considerable degree, the charge compensation between La
and Co
works in the equal (La, Co)-codoped case, where more than half of the Co ions are considered to be present in the minority spin
sites at the center of the oxygen tetrahedra, with the
= 3/2 state carrying a small orbital moment owing to spin-orbit interaction. The remaining small number of high-spin Co
(
= 3/2,
= 1) ions with unquenched orbital moments would be distributed to the other octahedral
,
, and
sites.
Cheung, Y. W.*; Hu, Y. J.*; Goh, S. K.*; Kaneko, Koji; Tsutsui, Satoshi; Logg, P. W.*; Grosche, F. M.*; Kanagawa, Hibiki*; Tanioku, Yasuaki*; Imai, Masaki*; et al.
Journal of Physics; Conference Series, 807(3), p.032002_1 - 032002_4, 2017/04
Times Cited Count:5 Percentile:81.80(Physics, Condensed Matter)Imai, Masaki; Michioka, Chishiro*; Ueda, Hiroaki*; Yoshimura, Kazuyoshi*
Physical Review B, 95(5), p.054417_1 - 054414_7, 2017/02
Times Cited Count:4 Percentile:20.53(Materials Science, Multidisciplinary)We took P NMR measurements of mainly paramagnetic phase
to reveal the itinerant-electron metamagnetic transition, and of its magnetically ordered phase, and characterized their spin fluctuations by estimating the spin fluctuation parameter
corresponding to the width of the spin fluctuation in the spectrum in frequency space. As
increases from 0 to 0.5, the in-plane component of
decreases proportionally with the metamagnetic transition field. In the antiferromagnetic cT phase,
is constant and spin fluctuations show an isotropic character in contrast to their behavior in the paramagnetic ucT phase. These results indicate that the in-plane spin fluctuations due to the quasi-two-dimensional crystal structure play a significant role in the metamagnetic transition of this system.
Cheung, Y. W.*; Zhang, J. Z.*; Zhu, J. Y.*; Yu, W. C.*; Hu, Y. J.*; Wang, D. G.*; Otomo, Yuka*; Iwasa, Kazuaki*; Kaneko, Koji; Imai, Masaki*; et al.
Physical Review B, 93(24), p.241112_1 - 241112_5, 2016/06
Times Cited Count:16 Percentile:56.77(Materials Science, Multidisciplinary)Koyama, Takehide*; Ozaki, Yuzuru*; Ueda, Koichi*; Mito, Takeshi*; Kohara, Takao*; Waki, Takeshi*; Tabata, Yoshikazu*; Michioka, Chishiro*; Yoshimura, Kazuyoshi*; Suzuki, Michito; et al.
Journal of the Physical Society of Japan, 81(Suppl.B), p.SB008_1 - SB008_5, 2012/12
Times Cited Count:1 Percentile:10.53(Physics, Multidisciplinary)The normal state properties of a noncentrosymmetric superconductor MoAl
C are studied by means of the nuclear magnetic resonance (NMR) experiment. The change of NMR line shape and the peak of the nuclear spin-echo decay rate at
130 K indicate that the Mo
Al
C exhibits the phase transition prior to the emergence of superconductivity. The reduction in the conduction electron density is inferred from the decrease in the nuclear spin-lattice relaxation rate. The nature of the newly found phase transition is discussed by considering the result of the first principle calculations, indicating a good nesting property of the Fermi surfaces.
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:56.67(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:56.67(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.
Koyama, Takehide*; Ozaki, Yuzuru*; Ueda, Koichi*; Mito, Takeshi*; Kohara, Takao*; Waki, Tsuyoshi*; Tabata, Yoshikazu*; Michioka, Chishiro*; Yoshimura, Kazuyoshi*; Suzuki, Michito; et al.
Physical Review B, 84(21), p.212501_1 - 212501_4, 2011/12
Times Cited Count:13 Percentile:48.17(Materials Science, Multidisciplinary)The results of Al nuclear magnetic resonance and specific-heat measurements of the noncentrosymmetric superconductor Mo
Al
C are reported. The phase transition around 130 K is inferred from a distinct change in the NMR spectrum, a clear peak in the spin-echo decay rate, and an anomaly in the specific heat. Possibility of charge-density wave ordering around 130 K is discussed by calculating the Fermi surfaces in the normal states and considering the partial quenching of the Fermi surfaces with the decrease in 1/
below the superconducting transition temperature.
Tomiyasu, Keisuke*; Kageyama, Hiroshi*; Lee, C.*; Whangbo, M. H.*; Tsujimoto, Yoshihiro*; Yoshimura, Kazuyoshi*; Taylor, J. W.*; Llobet, A.*; Trouw, F.*; Kakurai, Kazuhisa; et al.
Journal of the Physical Society of Japan, 79(3), p.034707_1 - 034707_4, 2010/03
Times Cited Count:16 Percentile:65.58(Physics, Multidisciplinary)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:84.63(Physics, Condensed Matter)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:58 Percentile:86.30(Physics, Multidisciplinary)no abstracts in English
Irizawa, Akinori*; Higashiya, Atsushi*; Kasai, Shuichi*; Sasabayashi, Takehisa*; Shigemoto, Akihiko*; Sekiyama, Akira*; Imada, Shin*; Suga, Shigemasa*; Sakai, Hironori; Ono, Hiroyuki*; et al.
Journal of the Physical Society of Japan, 75(9), p.094701_1 - 094701_5, 2006/09
Times Cited Count:6 Percentile:41.44(Physics, Multidisciplinary)Photoemission spectroscopy (PES) and O X-ray absorption spectroscopy (XAS) measurements have been performed for Cd
Re
O
single crystals. Temperature variations of their spectra reveal that the phase transition at 120 K directly changes the band structure near the Fermi level compared with another transition near 200 K. The roles of the transitions are discussed in terms of the changes in the Re-O orbital hybridization.
Lee, S.*; Park, J.-G.*; Adroja, D. T.*; Khomskii, D.*; Streltsov, S.*; McEwen, K. A.*; Sakai, Hironori; Yoshimura, Kazuyoshi*; Anisimov, V. I.*; Mori, Daisuke*; et al.
Nature Materials, 5(6), p.471 - 476, 2006/06
Times Cited Count:111 Percentile:94.42(Chemistry, Physical)Here we show that the three-dimensional cubic system of TlRu
O
most probably evolves into a one-dimensional spin-one Haldane system with a spin gap below 120 K, accompanied by anomalies in the structure, resistivity, and susceptibility. We argue that these anomalies are due to an orbital ordering of Ru
electrons, with a strong coupling among three degrees of freedom: orbital, spin, and lattice. Our work provides a unique example of the spontaneous formation of Haldane system with an insight into the intriguing interplay of different degrees of freedom.
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:81.01(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.
Inami, Toshiya; Owada, Kenji; Matsuda, Yasuhiro*; Ueda, Yuji*; Nojiri, Hiroyuki*; Murakami, Yoichi*; Arima, Takahisa*; Ota, Hiroto*; Zhang, W.*; Yoshimura, Kazuyoshi*
Nuclear Instruments and Methods in Physics Research B, 238(1-4), p.233 - 236, 2005/08
Times Cited Count:8 Percentile:52.40(Instruments & Instrumentation)Usually, X-ray diffraction experiments under strong magnetic fields are carried out using a superconducting magnet and the maximum field is limited up to 15T. In order to overcome this limitation, we have constructed an X-ray diffraction system combined with a pulsed magnet. The structural phase transition of PrCa
MnO
around 8 T and the valence transition of YbInCu
around 26 T are shown as a demonstration.
Sakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Kitagawa, Kentaro*; Murakawa, Hiroshi*; Ishida, Kenji*; Ono, Hiroyuki*; Kato, Masaki*; Yoshimura, Kazuyoshi*; Walstedt, R. E.
Journal of the Physical Society of Japan, 73(11), p.2940 - 2943, 2004/11
Times Cited Count:8 Percentile:47.87(Physics, Multidisciplinary)Cd NMR measurements have been performed in the superconducting (SC) state of the pyrochlore Cd
Re
O
at T
1 K, and in a field of less than 3 kOe below
. The upper critical field at 0.1 K has been determined to be 4 kOe from in situ measurements of the ac susceptibility. A reduction of the Knight shift in the SC state is confirmed. The present results provide strong evidence that this compound has a singlet SC pairing symmetry.
Sakai, Hironori; Ono, Hiroyuki*; Oba, Noriaki*; Kato, Masaki*; Yoshimura, Kazuyoshi*
Physica B; Condensed Matter, 329-333(2), p.1038 - 1039, 2003/05
Times Cited Count:5 Percentile:30.76(Physics, Condensed Matter)Pyrochlore iridium oxides PbCa
Ir
O
(
=0.0, 0.2, 0.4, 0.6, 0.8) were prepared by solid state reaction. The electrical resistivity and the magnetic susceptibility were measured between 4.2 and 300 K. These compounds show metallic conductivity and obey the Curie-Weiss law with temperature independent term. The metallic conductivity of Pb
Ir
O
is suppressed by the Ca substitution for Pb site.
Okane, Tetsuo; Fujimori, Shinichi; Mamiya, Kazutoshi; Okamoto, Jun; Fujimori, Atsushi; Tsujii, Naoto*; Yoshimura, Kazuyoshi*
Acta Physica Polonica B, 34(2), p.1019 - 1022, 2003/02
no abstracts in English