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Fe
intermetallic compoundCao, Y.*; Zhou, H.*; Khmelevskyi, S.*; Lin, K.*; Avdeev, M.*; Wang, C.-W.*; Wang, B.*; Hu, F.*; Kato, Kenichi*; Hattori, Takanori; et al.
Chemistry of Materials, 35(8), p.3249 - 3255, 2023/04
Times Cited Count：1 Percentile：0(Chemistry, Physical)Hydrostatic and chemical pressure are efficient stimuli to alter the crystal structure and are commonly used for tuning electronic and magnetic properties in materials science. However, chemical pressure is difficult to quantify and a clear correspondence between these two types of pressure is still lacking. Here, we study intermetallic candidates for a permanent magnet with a negative thermal expansion (NTE). Based on in situ synchrotron X-ray diffraction, negative chemical pressure is revealed in HoFe on Al doping and quantitatively evaluated by using temperature and pressure dependence of unit cell volume. A combination of magnetization and neutron diffraction measurements also allowed one to compare the effect of chemical pressure on magnetic ordering with that of hydrostatic pressure. Intriguingly, pressure can be used to control suppression and enhancement of NTE. Electronic structure calculations indicate that pressure affected the top of the majority band with respect to the Fermi level, which has implications for the magnetic stability, which in turn plays a critical role in modulating magnetism and NTE. This work presents a good example of understanding the effect of pressure and utilizing it to control properties of functional materials.
Fe
O
with distributed equivalent circuit modelFukada, 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：2 Percentile：30.35(Physics, Multidisciplinary)We report an analysis of the dielectric glasslike state of the spin- and charge-ordered system LuFeO, which has structural and physical properties analogous to those of the electronic ferroelectrics 
FeO
(: 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.
as the origin of volume collapseYu, 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：34 Percentile：70.17(Chemistry, Multidisciplinary)no abstracts in English
-type giant tetragonal compound BiZnVO
and its stability under pressureYu, 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：26 Percentile：62.59(Chemistry, Physical)no abstracts in English
Fe
O and zero-thermal expansion compositeNabetani, 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：60 Percentile：89.12(Physics, Applied)Negative thermal expansion (NTE) of BiNi
Fe
O
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
and Ni
in the controlled temperature range near room temperature. Compared with BiLnNiO (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.
IrSiPyon, 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：33 Percentile：82.71(Physics, Multidisciplinary) induced by intermetallic charge transferAzuma, 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：356 Percentile：99.06(Multidisciplinary Sciences)no abstracts in English
Isayama, Akihiko; Sakakibara, Satoru*; Furukawa, Masaru*; Matsunaga, Go; Yamazaki, Kozo*; Watanabe, Kiyomasa*; Idomura, Yasuhiro; Sakamoto, Yoshiteru; Tanaka, Kenji*; Tamura, Naoki*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 86(6), p.374 - 377, 2010/06
no abstracts in English
Osakabe, Masaki*; Shinohara, Koji; Toi, Kazuo*; Todo, Yasushi*; Hamamatsu, Kiyotaka; Murakami, Sadayoshi*; Yamamoto, Satoshi*; Idomura, Yasuhiro; Sakamoto, Yoshiteru; Tanaka, Kenji*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 85(12), p.839 - 842, 2009/12
no abstracts in English
Mn
O
(NO) oxynitrate comprising 
=3/2 honeycomb latticeSmirnova, 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：125 Percentile：91.93(Chemistry, Multidisciplinary)Neutron diffraction and FT-IR analysis revealed that the novel oxynitrate BiMnO (NO) prepared by hydrothermal synthesis is of a new structural type including flat NO layers alternating with blocks of two PbSbO
-like layers. Mn
(=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.
Idomura, Yasuhiro; Yoshida, Maiko; Yagi, Masatoshi*; Tanaka, Kenji*; Hayashi, Nobuhiko; Sakamoto, Yoshiteru; Tamura, Naoki*; Oyama, Naoyuki; Urano, Hajime; Aiba, Nobuyuki; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 84(12), p.952 - 955, 2008/12
no abstracts in English
NaCuOClHanaguri, 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：141 Percentile：95.65(Physics, Multidisciplinary)NaCuOClHanaguri, 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：6.7(Physics, Applied)We performed high-resolution scanning tunneling microscopy/spectroscopy on an optimally-doped CaNaCuOCl 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.
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：182 Percentile：95.3(Chemistry, Multidisciplinary)Structural properties of polycrystalline single-phased BiMnO 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 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 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.
Isobe, Mitsutaka*; Toi, Kazuo*; Matsushita, Hiroyuki*; Goto, Kazuyuki*; Suzuki, Chihiro*; Nagaoka, Kenichi*; Nakajima, Noriyoshi*; Yamamoto, Satoshi*; Murakami, Sadayoshi*; Shimizu, Akihiro*; et al.
Nuclear Fusion, 46(10), p.S918 - S925, 2006/10
Times Cited Count：30 Percentile：69.47(Physics, Fluids & Plasmas)no abstracts in English
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：278 Percentile：98.63(Chemistry, Physical)The crystal and magnetic structures of polycrystalline BiCoO have been determined by the Rietveldmethod from neutron diffraction data measured at temperatures from 5 to 520 K. BiCoO (space groupP4mm; Z=1; a=3.72937(7) 
and c=4.72382(15) at room temperature; tetragonality c/a=1.267) is isotypic with BaTiO and PbTiO in the whole temperature range. BiCoO 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
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)
and 2.93(2), respectively. The structure refinements revealed no deviation fromstoichiometry in BiCoO. BiCoO decomposed in air above 720 K to give CoO and sillenite-like Bi
CoO
.
Cu(PO) (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：33 Percentile：75.01(Materials Science, Multidisciplinary)Inelastic neutron scattering experiments were performed on ACu(PO) (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 ACu(PO) with A=Ca, Sr, and Pb, respectively.
Tezuka, Masashi; Iwai, Masaki; Sana, Kazuya; Higashiura, Norikazu
Proceedings of International Waste Management Symposium 2005 (WM '05) (CD-ROM), 0 Pages, 2005/00
Advanced Thermal Reactor Fugen Nuclear Power Station is planning to introduce 'spent resin volume reduction and stabilization processing device' and 'laundry drain filtering device' in radioactive waster treatment system. As for the former device, we demonstrated sufficient performance of this device by carrying out the confirmation test using real spent resin relating to the following points: performance of volume and weight reduction; change to inorganic material; detoxification; and retention and transfer of nuclide, etc. As for the latter device, we are studying two methods now. However, we confirmed that it is possible to apply the removal performance of radioactivity and Chemical Oxygen Demand to real machine by carrying out hot test.
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
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：11 Percentile：50.72(Physics, Condensed Matter)no abstracts in English
