Refine your search:     
Report No.
 - 
Search Results: Records 1-12 displayed on this page of 12
  • 1

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Magnetic properties of single crystalline YbFe$$_{2}$$O$$_{4}$$

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:97.61

We have investigated a single crystal of multiferroic YbFe$$_{2}$$O$$_{4}$$. 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.

Journal Articles

Multipole and superconducting state in PrIr$$_2$$Zn$$_{20}$$ probed by muon spin relaxation

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 ($$mu$$SR) in caged structural heavy fermion system PrIr$$_2$$Zn$$_{20}$$ to elucidate magnetic and superconducting properties. Temperature independent $$mu$$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 $$T_c$$=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 $$^{141}$$Pr nuclei and muon realize in PrIr$$_2$$Zn$$_{20}$$.

Journal Articles

Doping effect on charge ordered structure in Mn-doped YbFe$$_{2}$$O$$_{4}$$

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:0.09

Changes of charge ordered (CO) structure by partial substitution of Mn for Fe in YbFe$$_{2}$$O$$_{4}$$ were investigated by a transmission electron microscope (TEM), incombination with conventional dielectric measurement. It is revealed that partial substitution of Mn$$^{2+}$$ for Fe$$^{2+}$$ in YbFe$$_{2}$$O$$_{4}$$ 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$$_{4}$$. The random distribution of polar clustering structure gives rise to characteristic broad dielectric dispersion.

Journal Articles

Collapsing processes of charge ordered structure in charge- and spin- frustrated ferrite YbFe$$_{2}$$O$$_{4}$$

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:0.03

In order to clarify the stability of charge ordered structure (CO) in charge- and spinfrustrated ferrite YbFe$$_{2}$$O$$_{4}$$, we have investigated changes of the CO structure by partial substitution of Mn$$^{2+}$$ for Fe$$^{2+}$$ in YbFe$$_{2}$$O$$_{4}$$ by a transmission electron microscope (TEM), incombination with conventional dielectric measurement. It is revealed that subtle substitution of Mn$$^{2+}$$ for Fe$$^{2+}$$ in YbFe$$_{2}$$O$$_{4}$$ 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.

Journal Articles

Strain measurement under loading in laser weld on austenitic stainless steel using high-energy synchrotron radiation

Matsumoto, Keisuke*; Shobu, Takahisa; Akiniwa, Yoshiaki*; Yagi, Tsuyoshi*; Yamamoto, Masataka*

Zairyo, 57(7), p.654 - 659, 2008/07

Journal Articles

Measurement of strain distribution around weld zone for railway carbody structure using high-energy synchrotron radiation

Matsumoto, Keisuke*; Shobu, Takahisa; Akiniwa, Yoshiaki*; Yagi, Tsuyoshi*; Yamamoto, Masataka*

Materials Science Forum, 571-572, p.321 - 326, 2008/00

JAEA Reports

Study on the prediction accuracy of nuclide generation and depletion with JENDL

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

JAERI-Research-2004-025.pdf:19.46MB

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$$_{2}$$ 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.

Oral presentation

Evaluation of fatigue damage around the weld zones of railway carbody structures using high-energy synchrotron radiation

Shobu, Takahisa; Matsumoto, Keisuke*; Yamamoto, Masataka*; Yagi, Tsuyoshi*; Okino, Tomohiro*

no journal, , 

no abstracts in English

Oral presentation

Charge-order structure and physical properties of YbFe$$_{2-x}$$Mn$$_{x}$$O$$_{4}$$

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 YbFe$$_{2-x}$$Mn$$_{x}$$O$$_{4}$$. 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.

Oral presentation

Magnetic/dielectric properties and charge ordering phenomenain YbFe$$_{2-x}$$Mn$$_{x}$$O$$_{4}$$, 2

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 YbFe$$_{2-x}$$Mn$$_{x}$$O$$_{4}$$, a derivative system of the electronic ferroelectric RFe$$_{2}$$O$$_{4}$$ (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.

Oral presentation

Development of neutron spectrum measurement in high $$gamma$$ field using new nuclear emulsion, 2; Recognition algorithm for recoiled proton track based on three dimensional analysis of the novel nuclear emulsion

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 $$gamma$$-ray field, in order to control $$gamma$$-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.

Oral presentation

$$mu$$SR study on PrIr$$_2$$Zn$$_{20}$$ under magnetic field

Higemoto, Wataru; Okazawa, Takeshi; Oshima, Kohei*; Ito, Takashi; Robert, S.*; Matsumoto, Keisuke*; Onimaru, Takahiro*

no journal, , 

no abstracts in English

12 (Records 1-12 displayed on this page)
  • 1