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Yoshii, Kenji; Mizumaki, Masaichiro*; Matsumoto, Keisuke*; Mori, Shigeo*; Endo, Naruki; Saito, Hiroyuki; Matsumura, Daiju; Kambe, Takashi*; Ikeda, Naoshi*
Journal of Physics; Conference Series, 428, p.012032_1 - 012032_5, 2013/04
Times Cited Count:13 Percentile:97.61We have investigated a single crystal of multiferroic YbFeO
. Its magnetic transition temperature was 250 K. The magnetization along the c-axis was much larger than that within the ab plane, indicating the Ising character of this system. The field-cooled magnetization became negative below 10 K. This was explained in terms of an antiparallel coupling between Yb and Fe moments. Magnetocaloric effects were also observed. The change of entropy was found to show a broad peak with a width of 100 K, which is favorable to application.
Higemoto, Wataru; Ito, Takashi; Ninomiya, Kazuhiko; Onimaru, Takahiro*; Matsumoto, Keisuke*; Takabatake, Toshiro*
Physical Review B, 85(23), p.235152_1 - 235152_4, 2012/06
Times Cited Count:2 Percentile:11.18(Materials Science, Multidisciplinary)We performed muon spin rotation and relaxation measurements (SR) in caged structural heavy fermion system PrIr
Zn
to elucidate magnetic and superconducting properties. Temperature independent
SR spectra were observed below 1K, indicating that the phase transition at 0.11K is non-magnetic origin, most probably pure quadrupole ordering. In the superconducting phase, no sign of unconventional superconductivity, like a broken time reversal symmetry superconductivity, is seen below
=0.05K. Moreover, we have observed spontaneous muon spin precession in a zero field in the paramagnetic phase below 15K, suggesting a novel coupling between
Pr nuclei and muon realize in PrIr
Zn
.
Matsumoto, Keisuke*; Koyama, Tsukasa*; Mori, Shigeo*; Yoshii, Kenji; Kambe, Takashi*; Ikeda, Naoshi*
IOP Conference Series; Materials Science and Engineering, 18(9), p.092047_1 - 092047_4, 2011/09
Times Cited Count:0 Percentile:0.09Changes of charge ordered (CO) structure by partial substitution of Mn for Fe in YbFeO
were investigated by a transmission electron microscope (TEM), incombination with conventional dielectric measurement. It is revealed that partial substitution of Mn
for Fe
in YbFe
O
destroyed drastically the CO structure with the wave vector of q=
1/3 1/3 1/2
. Consequently polar clustering structure giving rise to honeycomb-shaped diffuse streaks was found in YbFeMnO
. The random distribution of polar clustering structure gives rise to characteristic broad dielectric dispersion.
Matsumoto, Keisuke*; Koyama, Tsukasa*; Mori, Shigeo*; Yoshii, Kenji; Ikeda, Naoshi*
Journal of Physics; Conference Series, 320, p.012085_1 - 012085_5, 2011/09
Times Cited Count:0 Percentile:0.03In order to clarify the stability of charge ordered structure (CO) in charge- and spinfrustrated ferrite YbFeO
, we have investigated changes of the CO structure by partial substitution of Mn
for Fe
in YbFe
O
by a transmission electron microscope (TEM), incombination with conventional dielectric measurement. It is revealed that subtle substitution of Mn
for Fe
in YbFe
O
destroyed drastically the CO structure with the wave vector of q=
1/3 1/3 1/2
and, instead, induced polar clustering structure characterized by honeycomb shaped diffuse scatterings in the reciprocal space. The formation of polar clustering structure should be responsible for the characteristic dielectric dispersion.
Matsumoto, Keisuke*; Shobu, Takahisa; Akiniwa, Yoshiaki*; Yagi, Tsuyoshi*; Yamamoto, Masataka*
Zairyo, 57(7), p.654 - 659, 2008/07
Matsumoto, Keisuke*; Shobu, Takahisa; Akiniwa, Yoshiaki*; Yagi, Tsuyoshi*; Yamamoto, Masataka*
Materials Science Forum, 571-572, p.321 - 326, 2008/00
Okumura, Keisuke; Oki, Shigeo*; Yamamoto, Munenari*; Matsumoto, Hideki*; Ando, Yoshihira*; Tsujimoto, Kazufumi; Sasahara, Akihiro*; Katakura, Junichi; Matsumura, Tetsuo*; Aoyama, Takafumi*; et al.
JAERI-Research 2004-025, 154 Pages, 2005/01
This report summarizes the activity (FY2000-2003) of Working Group (WG) on Evaluation of Nuclide Generation and Depletion under Subcommittee on Nuclear Fuel Cycle of Japanese Nuclear Data Committee. In the WG, analyses of Post Irradiation Examinations have been carried out for UO and MOX fuels irradiated in PWRs, BWRs and FBRs, and for actinide samples irradiated in fast reactors, by using ORIGEN or more detailed calculation codes with their libraries based on JENDL-3.2, JENDL-3.3 and other foreign nuclear data files. From these results, current prediction accuracy and problems for evaluation of nuclide generation and depletion are discussed. Furthermore, this report covers other products of our activity; development of the ORIGEN libraries for PWR, BWR and FBR based on JENDL-3.3, study on introduction of neutron spectrum index to ORIGEN calculations, and results of questionnaire survey on desirable accuracy of ORIGEN calculations.
Shobu, Takahisa; Matsumoto, Keisuke*; Yamamoto, Masataka*; Yagi, Tsuyoshi*; Okino, Tomohiro*
no journal, ,
no abstracts in English
Matsumoto, Keisuke*; Matsuo, Yoji*; Oishi, Daisuke*; Akahama, Yuji*; Yoshii, Kenji; Hanasaki, Noriaki*; Kambe, Takashi*; Ikeda, Naoshi*; Kimizuka, Noboru*; Mori, Shigeo*
no journal, ,
We have investigated the charge-ordered structure and physical properties of YbFeMn
O
. Electron diffraction measurements showed a disappearance of charge-ordered structure of Fe ions by the Mn substitution. The Mn substitution also led to a monotonic decrease in magnetic transition temperature, low-temperature magnetization and dielectric constants. The results are explained in connection with several factors such as short-range ionic order.
Matsumoto, Keisuke*; Hoshiyama, Takuya*; Oishi, Daisuke*; Akahama, Hiroshi*; Yoshii, Kenji; Kano, Jun*; Hanasaki, Noriaki*; Kambe, Takashi*; Ikeda, Naoshi*; Mori, Shigeo*
no journal, ,
We have investigated the physical properties of YbFeMn
O
, a derivative system of the electronic ferroelectric RFe
O
(R: rare earths). Electron diffraction measurements showed taht long-range charge ordering of the Fe-3d charges was observed at room temperature for x=0; this ordering is the origin of ferroelectricity. The x=0.1 oxide showed diffuse scattering patterns at room temperature, instead of the charge-ordered pattern. Thus, 5% Mn substitution can collapse the long-range charge ordering. We will also present the correlation between the magnetic/dielectric properties and the crystal structure.
Takagi, Keisuke*; Ishihara, Kohei*; Tomita, Hideki*; Kawarabayashi, Jun*; Iguchi, Tetsuo*; Morishima, Kunihiro*; Maeda, Shigetaka; Matsumoto, Tetsuro*
no journal, ,
In the novel nuclear emulsion development to measurement a neutron spectrum in high -ray field, in order to control
-ray sensitivity, the ArBr grains of about 100 nm of particle diameter is used. The recoil proton track induced by neutron is recorded on nuclear emulsion. The track constituted by a silver grains child standing in a row discretely is recorded. The track extraction algorithm suitable for extraction of recoil proton was developed, and the characteristic was evaluated.
Higemoto, Wataru; Okazawa, Takeshi; Oshima, Kohei*; Ito, Takashi; Robert, S.*; Matsumoto, Keisuke*; Onimaru, Takahiro*
no journal, ,
no abstracts in English