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Uechi, Shoichi*; Oyama, Kenji*; Fukumoto, Yohei*; Kanazawa, Yuki*; Happo, Naohisa*; Harada, Masahide; Inamura, Yasuhiro; Oikawa, Kenichi; Matsuhra, Wataru*; Iga, Fumitoshi*; et al.
Physical Review B, 102(5), p.054104_1 - 054104_10, 2020/08
Times Cited Count:7 Percentile:53.71(Materials Science, Multidisciplinary)Iwasa, Kazuaki*; Iga, Fumitoshi*; Moyoshi, Taketo*; Nakao, Akiko*; Ohara, Takashi
Journal of the Physical Society of Japan, 87(6), p.064705_1 - 064705_5, 2018/06
Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)Inami, Toshiya; Michimura, Shinji*; Hayashi, Yuya*; Matsumura, Takeshi*; Sera, Masafumi*; Iga, Fumitoshi*
Physical Review B, 90(4), p.041108_1 - 041108_5, 2014/07
Times Cited Count:9 Percentile:40.44(Materials Science, Multidisciplinary)We carried out a high-resolution X-ray diffraction experiment on CeLa
B
. This compound exhibits antiferro-octupole order (AFO) below
= 1.4 K, and it is theoretically suggested that ferroquadrupole moments and a resultant rhombohedral deformation are induced in the AFO phase. We observe the splitting of Bragg reflections below
and find that the unit cell is rhombohedral with the elongated [111] axis. We also precisely evaluate the magnitude of the induced quadrupole moments from the obtained shear strain and find that the quadrupole moments are not reduced in the AFO phase.
Matsumura, Takeshi*; Michimura, Shinji*; Inami, Toshiya; Otsubo, Toru*; Tanida, Hiroshi*; Iga, Fumitoshi*; Sera, Masafumi*
JPS Conference Proceedings (Internet), 3, p.014008_1 - 014008_6, 2014/06
We study the -type antiferro-octupole (AFO) ordered state of Ce
La
B
below 1.5 K by resonant X-ray diffraction in magnetic fields. Multipole moments induced by the field in the AFO phase are identified. In a mean-field model for the
AFO order within the
quartet crystal-field ground state, the
and
antiferroquadrupoles (AFQ) are expected as mostly induced AFQ. However, in contrast to this expectation, the main induced moment is found to be the
-type AFQ.
Masuda, Ryo*; Kobayashi, Yasuhiro*; Kitao, Shinji*; Kurokuzu, Masayuki*; Saito, Makina*; Yoda, Yoshitaka*; Mitsui, Takaya; Iga, Fumitoshi*; Seto, Makoto
Applied Physics Letters, 104(8), p.082411_1 - 082411_5, 2014/02
Times Cited Count:19 Percentile:63.93(Physics, Applied)A detection system for synchrotron-radiation (SR)-based Mssbauer spectroscopy was developed to enhance the nuclear resonant scattering counting rate and thus increase the available nuclides. In the system, a windowless avalanche photodiode (APD) detector was combined with a vacuum cryostat to detect the internal conversion (IC) electrons and fluorescent X-rays accompanied by nuclear de-excitation. As a feasibility study, the SR-based M
ssbauer spectrum using the 76.5 keV level of
Yb was observed without
Yb enrichment of the samples. The counting rate was five times higher than that of our previous system, and the spectrum was obtained within 10 h. This result shows that nuclear resonance events can be more efficiently detected by counting IC electrons for nuclides with high IC coefficients. Furthermore, the windowless detection system enables us to place the sample closer to the APD elements and is advantageous for nuclear resonant inelastic scattering measurements. Therefore, this detection system can not only increase the number of nuclides accessible in SR-based M
ssbauer spectroscopy but also allows the nuclear resonant inelastic scattering measurements of small single crystals or enzymes with dilute probe nuclides that are difficult to measure with the previous detection system.
Matsumura, Takeshi*; Michimura, Shinji*; Inami, Toshiya; Otsubo, Toru*; Tanida, Hiroshi*; Iga, Fumitoshi*; Sera, Masafumi*
Physical Review B, 89(1), p.014422_1 - 014422_13, 2014/01
Times Cited Count:14 Percentile:54.07(Materials Science, Multidisciplinary)The multipole ordered phase in CeLa
B
(phase IV) has been studied by resonant X-ray diffraction in magnetic fields. By utilizing diamond X-ray phase plates to rotate the incident linear polarization and a conventional crystal analyzer system, full linear polarization analysis has been performed to identify the order parameters. The analysis shows that the
quadrupoles are more induced by the field than the
quadrupoles in phase IV, in disagreement with mean-field calculations, in which the
quadrupole is the main induced moment. Hence, we consider that large fluctuations of the
quadrupole is hidden behind the primary ordering of the octupole.
Matsuda, Yasuhiro*; Murata, Yuto*; Inami, Toshiya; Owada, Kenji; Nojiri, Hiroyuki*; Oyama, Kenji*; Kato, Naoki*; Murakami, Yoichi*; Iga, Fumitoshi*; Takabatake, Toshiro*; et al.
Journal of Physics; Conference Series, 51, p.490 - 493, 2006/00
Times Cited Count:8 Percentile:92.65Shamoto, Shinichi; Tsubota, Masami*; Iga, Fumitoshi*; Fk, B.*; Kajitani, Tsuyoshi*
Journal of Neutron Research, 13(1-3), p.175 - 178, 2005/03
YTiO with T
~30 K has been studied by the MARI spectrometer with E
=130 meV and 500 meV at T=5 K, 40K, and 200 K. We have not found any clear orbital excitation in a wide Q-E range (0.5
Q
25
, 6
E
350 meV). The intensity of orbital excitation would be significantly weak in comparison with the phonon.
Ikushima, Kenji; Kato, Y.*; Takigawa, Masashi*; Iga, Fumitoshi*; Hiura, Sayaka*; Takabatake, Toshiro*
Physica B; Condensed Matter, 281-282, p.274 - 275, 2000/06
Times Cited Count:22 Percentile:71.62(Physics, Condensed Matter)no abstracts in English
Ito, Takashi; Higemoto, Wataru; Ninomiya, Kazuhiko; Iga, Fumitoshi*
no journal, ,
no abstracts in English
Ito, Takashi; Higemoto, Wataru; Ninomiya, Kazuhiko; Iga, Fumitoshi*
no journal, ,
no abstracts in English
Michimura, Shinji; Inami, Toshiya; Otsubo, Toru*; Matsumura, Takeshi*; Tanida, Hiroshi*; Sera, Masafumi*; Iga, Fumitoshi*
no journal, ,
no abstracts in English
Higemoto, Wataru; Ito, Takashi; Ninomiya, Kazuhiko; Iga, Fumitoshi*; Fukuta, Kenji*; Takabatake, Toshiro*
no journal, ,
It is well known that RB (R: rear-earth element) exhibit variety of properties. For example, CeB
is considered as a typical compound of Kondo lattice system and many studies have been carried out from the viewpoints of multipole ordering etc. TmB
is interesting compound due to its possible valence fluctuation. However, material synthesis have not been reported yet. Mean while, YnB
shows non magnetic ground state. We have carried out muon spin relaxation (
SR) measurements in polycrystalline specimen of Tm
Yb
B
to elucidate magnetic ground state. As a result, we have clearly observed local magnetic field below 2K and evidently, whole the system is in magnetic ordering state.
Inami, Toshiya; Michimura, Shinji*; Hayashi, Yuya*; Matsumura, Takeshi*; Sera, Masafumi*; Iga, Fumitoshi*
no journal, ,
no abstracts in English
Inami, Toshiya; Michimura, Shinji*; Hayashi, Yuya*; Matsumura, Takeshi*; Sera, Masafumi*; Iga, Fumitoshi*
no journal, ,
no abstracts in English
Inami, Toshiya; Michimura, Shinji*; Matsumura, Takeshi*; Hayashi, Yuya*; Sera, Masafumi*; Iga, Fumitoshi*
no journal, ,
We have carried out a high-resolution X-ray diffraction experiment at low temperatures and in magnetic fields on CeLa
B
that exhibits antiferrooctupole (AFO) order below
=1.4K. Ferroquadrupole moments that accompany the AFO order and a resultant rhombohedral deformation of the cubic lattice were theoretically predicted and experimetanlly supported. However, the sign and magnitude of the rhombohedral deformation have not yet been determined. We observe the splitting of Bragg peaks below
, which is consistent with a rhombohedral deformation of 4
elongated along the [111] axis. The response of rhombohedral domains to magnetic fields also well agrees with theoretical calculations. A particular outcome of this experiment is that the magnitude of the induced quadrupole moments is precisely evaluated from the obtained shear strain.