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Journal Articles

Analysis of glass behavior of Lu$$_{2}$$Fe$$_{3}$$O$$_{7}$$ with distributed equivalent circuit model

Fukada, Yukimasa*; Fukuyama, Ryota*; Fujiwara, Kosuke*; Yoshii, Kenji; Shigematsu, Kei*; Azuma, Masaki*; Ikeda, Naoshi*

Journal of the Physical Society of Japan, 90(2), p.024710_1 - 024710_6, 2021/02

 Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)

We report an analysis of the dielectric glasslike state of the spin- and charge-ordered system Lu$$_{2}$$Fe$$_{3}$$O$$_{7}$$, which has structural and physical properties analogous to those of the electronic ferroelectrics ${it R}$Fe$$_{2}$$O$$_{4}$$ (${it R}$: rare earth). Aging and memory effects of resistivity were found in the electric impedance response. We performed a numerical analysis with equivalent electric circuits that have a logarithmic Gaussian distribution of resistance and capacitance. The distribution parameters well explained the glassy nature of the electric and dielectric properties between 100 and 200 K and the distribution variations of charge- and magnetic-ordered domains underlying the glass nature.

Journal Articles

Melting of Pb charge glass and simultaneous Pb-Cr charge transfer in PbCrO$$_{3}$$ as the origin of volume collapse

Yu, R.*; Hojo, Hajime*; Watanuki, Tetsu; Mizumaki, Masaichiro*; Mizokawa, Takashi*; Oka, Kengo*; Kim, H.*; Machida, Akihiko; Sakaki, Koji*; Nakamura, Yumiko*; et al.

Journal of the American Chemical Society, 137(39), p.12719 - 12728, 2015/10

 Times Cited Count:23 Percentile:65.97(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

New PbTiO$$_{3}$$-type giant tetragonal compound Bi$$_{2}$$ZnVO$$_{6}$$ and its stability under pressure

Yu, R.*; Hojo, Hajime*; Oka, Kengo*; Watanuki, Tetsu; Machida, Akihiko; Shimizu, Keisuke*; Nakano, Kiho*; Azuma, Masaki*

Chemistry of Materials, 27(6), p.2012 - 2017, 2015/03

 Times Cited Count:21 Percentile:64.2(Chemistry, Physical)

no abstracts in English

Journal Articles

Suppression of temperature hysteresis in negative thermal expansion compound BiNi$$_{1-x}$$Fe$$_{x}$$O$$_{3}$$ and zero-thermal expansion composite

Nabetani, Koichiro*; Muramatsu, Yuya*; Oka, Kengo*; Nakano, Kiho*; Hojo, Hajime*; Mizumaki, Masaichiro*; Agui, Akane; Higo, Yuji*; Hayashi, Naoaki*; Takano, Mikio*; et al.

Applied Physics Letters, 106(6), p.061912_1 - 061912_5, 2015/02

 Times Cited Count:48 Percentile:89.86(Physics, Applied)

Negative thermal expansion (NTE) of BiNi$$_{1_x}$$Fe$$_x$$O$$_3$$ is investigated by dilatometric curves, synchrotron X-ray diffraction, and X-ray absorption spectroscopy. All samples (x=0.05-0.15) shows large NTE with the coefficient of linear thermal expansion which induced by charge transfer between Bi$$^{5+}$$ and Ni$$^{2+}$$ in the controlled temperature range near room temperature. Compared with Bi$$_{1_x}$$Ln$$_x$$NiO$$_3$$ (Ln: rare-earth elements), the thermal hysteresis that causes a problem for practical application is suppressed because random distribution of Fe in the Ni site changes the first order transition to second order-like transition.

Journal Articles

Superconductivity in noncentrosymmetric iridium silicide Li$$_2$$IrSi$$_3$$

Pyon, S.*; Kudo, Kazutaka*; Matsumura, Junichi*; Ishii, Hiroyuki*; Matsuo, Genta*; Nohara, Minoru*; Hojo, Hajime*; Oka, Kengo*; Azuma, Masaki*; Garlea, V. O.*; et al.

Journal of the Physical Society of Japan, 83(9), p.093706_1 - 093706_5, 2014/09

 Times Cited Count:26 Percentile:81.51(Physics, Multidisciplinary)

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:283 Percentile:98.92(Multidisciplinary Sciences)

no abstracts in English

Journal Articles

Synthesis, crystal structure, and magnetic properties of Bi$$_3$$Mn$$_4$$O$$_{12}$$(NO$$_3$$) oxynitrate comprising $$S$$=3/2 honeycomb lattice

Smirnova, O.*; Azuma, Masaki*; Kumada, Nobuhiro*; Kusano, Yoshihiro*; Matsuda, Masaaki; Shimakawa, Yuichi*; Takei, Takahiro*; Yonesaki, Yoshinori*; Kinomura, Nobukazu*

Journal of the American Chemical Society, 131(23), p.8313 - 8317, 2009/05

 Times Cited Count:109 Percentile:91.5(Chemistry, Multidisciplinary)

Neutron diffraction and FT-IR analysis revealed that the novel oxynitrate Bi$$_3$$Mn$$_4$$O$$_{12}$$ (NO$$_3$$) prepared by hydrothermal synthesis is of a new structural type including flat NO$$_3$$ layers alternating with blocks of two PbSb$$_2$$O$$_6$$-like layers. Mn$$^{4+}$$ ($$S$$=3/2) forms a regular honeycomb lattice, and magnetic susceptibility data indicated two-dimensional magnetism. Despite its Weiss constant of $$-$$257K, no long-range ordering was observed down to 0.4K because of the magnetic frustration due to the competition between the nearest and the next-nearest antiferromagnetic interactions.

Journal Articles

Quasiparticle interference and superconducting gap in Ca$$_{2-x}$$Na$$_x$$CuO$$_2$$Cl$$_2$$

Hanaguri, Tetsuo*; Kosaka, Yuki*; Davis, J. C.*; Lupien, C.*; Yamada, Ikuya*; Azuma, Masaki*; Takano, Mikio*; Oishi, Kazuki; Ono, Masaki*; Takagi, Hidenori*

Nature Physics, 3(12), p.865 - 871, 2007/12

 Times Cited Count:134 Percentile:95.94(Physics, Multidisciplinary)

Journal Articles

Low-energy spectroscopic mapping studies in optimally-doped Ca$$_{2-x}$$Na$$_x$$CuO$$_2$$Cl$$_2$$

Hanaguri, Tetsuo*; Kosaka, Yuki*; Davis, J. C.*; Lupien, C.*; Yamada, Ikuya*; Azuma, Masaki*; Takano, Mikio*; Oishi, Kazuki; Takagi, Hidenori*

Physica C, 460-462, p.954 - 955, 2007/09

 Times Cited Count:1 Percentile:7.1(Physics, Applied)

We performed high-resolution scanning tunneling microscopy/spectroscopy on an optimally-doped Ca$$_{2-x}$$Na$$_x$$CuO$$_2$$Cl$$_2$$ crystal. The so-called checkerboard local-density-of-state modulation manifests in the spectroscopic map of the optimally-doped sample. In addition, spatially-inhomogeneous energy gap is observed. The gap tends to be buried at elevated temperatures and correlates with the checkerboard modulation. These results suggest that the gap is related to superconductivity which coexists with the checkerboard modulation.

Journal Articles

Origin of the monoclinic-to-monoclinic phase transition and evidence for the centrosymmetric crystal structure of BiMnO$$_3$$

Belik, A. A.*; Iikubo, Satoshi; Yokosawa, Tadahiro*; Kodama, Katsuaki; Igawa, Naoki; Shamoto, Shinichi; Azuma, Masaki*; Takano, Mikio*; Kimoto, Koji*; Matsui, Yoshio*; et al.

Journal of the American Chemical Society, 129(4), p.971 - 977, 2007/01

 Times Cited Count:167 Percentile:95.31(Chemistry, Multidisciplinary)

Structural properties of polycrystalline single-phased BiMnO$$_3$$ samples prepared at 6 GPa and 1383 K have been studied by selected area electron diffraction (SAED), convergent beam electron diffraction (CBED), and the Rietveld method using neutron diffraction data measured at 300 and 550 K. The SAED and CBED data showed that BiMnO$$_3$$ crystallizes in the centrosymmetric space group C2/c at 300 K. The analysis of Mn-O bond lengths suggested that the orbital order present in BiMnO$$_3$$ at 300 K melts above T= 474 K. The phase transition at 474 K is of the first order and accompanied by a jump of magnetization and small changes of the effective magnetic moment and Weiss temperature.

Journal Articles

Neutron powder diffraction study on the crystal and magnetic structures of BiCoO$$_3$$

Belik, A. A.*; Iikubo, Satoshi; Kodama, Katsuaki; Igawa, Naoki; Shamoto, Shinichi; Niitaka, Seiji*; Azuma, Masaki*; Shimakawa, Yuichi*; Takano, Mikio*; Izumi, Fujio*; et al.

Chemistry of Materials, 18(3), p.798 - 803, 2006/02

 Times Cited Count:241 Percentile:98.55(Chemistry, Physical)

The crystal and magnetic structures of polycrystalline BiCoO$$_3$$ have been determined by the Rietveldmethod from neutron diffraction data measured at temperatures from 5 to 520 K. BiCoO$$_3$$ (space groupP4mm; Z=1; a=3.72937(7) ${AA}$ and c=4.72382(15) ${AA}$ at room temperature; tetragonality c/a=1.267) is isotypic with BaTiO$$_3$$ and PbTiO$$_3$$ in the whole temperature range. BiCoO$$_3$$ is an insulator with a Neeltemperature of 470 K. A possible model for antiferromagnetic order is proposed with a propagationvector of k=(1/2, 1/2, 0). In this model, magnetic moments of Co$$^{3+}$$ ions are parallel to the c directionand align antiferromagnetically in the ab plane. The antiferromagnetic ab layers stack ferromagneticallyalong the c axis, forming a C-type antiferromagnetic structure. Refined magnetic moments at 5 and 300K are 3.24(2)$$mu$$$$_B$$ and 2.93(2)$$mu$$$$_B$$, respectively. The structure refinements revealed no deviation fromstoichiometry in BiCoO$$_3$$. BiCoO$$_3$$ decomposed in air above 720 K to give Co$$_3$$O$$_4$$ and sillenite-like Bi$$_{25}$$CoO$$_{39}$$.

Journal Articles

Magnetic excitations from the linear Heisenberg antiferromagnetic spin trimer system A$$_3$$Cu$$_3$$(PO$$_4$$)$$_4$$ (A=Ca, Sr, and Pb)

Matsuda, Masaaki; Kakurai, Kazuhisa; Belik, A. A.*; Azuma, Masaki*; Takano, Mikio*; Fujita, Masaki*

Physical Review B, 71(14), p.144411_1 - 144411_5, 2005/04

 Times Cited Count:29 Percentile:73.55(Materials Science, Multidisciplinary)

Inelastic neutron scattering experiments were performed on A$$_3$$Cu$$_3$$(PO$$_4$$)$$_4$$ (A=Ca, Sr, and Pb), which consists of one-dimensional array of linear copper spin trimers. It was found that the magnetic excitations are well described by the linear Heisenberg antiferromagnetic spin trimer model without adjustable parameters except the overall scale factor. The intra-trimer coupling contants are determined to be 9.39(4), 9.99(4), and 9.07(4) meV for A$$_3$$Cu$$_3$$(PO$$_4$$)$$_4$$ with A=Ca, Sr, and Pb, respectively.

Journal Articles

Experiences of Remote Operated Dismantling of Glove-Box

Okada, Takashi; Asazuma, Shinichiro; Kashiro, Kashio; Matsumoto, Masaki

CD-ROM, WM-5214, p.8, 8 Pages, 2005/00

The dismantling activities, which consist of removal of the glove panel, dismantling of the interior equipment and dismantling of the GB body and made up about 45% of the dismantling of the GB in GBDF, could be performed by remote control.

JAEA Reports

Scattering Profiles of Sparks and Combustibility of Filter against Hot Sparks

Asazuma, Shinichiro; Okada, Takashi; Kashiro, Kashio; Matsumoto, Masaki; Nakata, Keiji*; Gonnokami, Kiyomi*; Toda, Rikiya*

JNC TN8430 2003-011, 56 Pages, 2004/01


The glove-box dismantling facility in the Plutonium Fuel Production Facility is developed to dismantle after-service glove-boxes with remote-controlled devices such as an arm-type manipulator. An abrasive wheel cutter, which is used to size reduce the gloveboxes, generates sparks during operation. This dispersing spark was a problem from the fire prevention point of view. A suitable spark control measures for this operation were required. We developed panels to minimize spark dispersion, shields to prevent the income of sparks to the pre-filter, and incombustible pre-filters. The equipment was tested and effectiveness was confirmed. This report provides the results of these tests.

Journal Articles

Synthesis of materials under high pressure by means of synchrotron X-ray diffraction

Azuma, Masaki*; Saito, Takashi*; Niitaka, Seiji*; Ishiwata, Shintaro*; Kanda, Hiroaki*; Yamada, Ikuya*; Takano, Mikio*; Utsumi, Wataru

Kotai Butsuri, 38(2), p.141 - 150, 2003/02

no abstracts in English

Journal Articles

Single-crystal growth of transition metal oxides at high pressures of several GPa

Azuma, Masaki*; Saito, Takashi*; Ishiwata, Shintaro*; Yoshida, Hirofumi*; Takano, Mikio*; Kosaka, Yuki*; Takagi, Hidenori*; Utsumi, Wataru

Journal of Physics; Condensed Matter, 14(44), p.11321 - 11324, 2002/11

 Times Cited Count:7 Percentile:39.68(Physics, Condensed Matter)

no abstracts in English

Journal Articles

Single crystal growth of the high pressure phase of (VO)$$_{2}$$P$$_{2}$$O$$_{7}$$ at 3GPa

Saito, Takashi*; Terashima, Takashi*; Azuma, Masaki*; Takano, Mikio*; Goto, Tadashi*; Ota, Hiroshi*; Utsumi, Wataru; Bordet, P.*; Johnston, D. C.*

Journal of Solid State Chemistry, 153(1), p.124 - 131, 2000/08

 Times Cited Count:35 Percentile:79.22(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

In situ X-ray diffraction experiments under high pressures and high temperatures at BL14B1 beamline

Utsumi, Wataru; Katayama, Yoshinori; Mizutani, Takeshi; Shimomura, Osamu; Yamakata, Masaaki*; Azuma, Masaki*; Saito, Takashi*

Nihon Kessho Gakkai-Shi, 42(1), p.59 - 67, 2000/02

no abstracts in English

Journal Articles

Magnetic properties and single crystal growth of a spin gapped compound, high pressure phase of (VO)$$_{2}$$P$$_{2}$$O$$_{7}$$

Saito, Takashi*; Azuma, Masaki*; Takano, Mikio*; Hiroi, Zenji*; Narumi, Yasuo*; Kindo, Koichi*; Utsumi, Wataru

Funtai Oyobi Fummatsu Yakin, 46(9), p.1014 - 1019, 1999/09

no abstracts in English

Oral presentation

Direct observation of the Ni-3d electronic states change in PrNiO$$_{3}$$

Mizumaki, Masaichiro*; Agui, Akane; Saito, Takashi*; Azuma, Masaki*; Shimakawa, Yuichi*; Takano, Mikio*; Uozumi, Takayuki*

no journal, , 

no abstracts in English

33 (Records 1-20 displayed on this page)