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Journal Articles

Pressure-modulated magnetism and negative thermal expansion in the Ho$$_2$$Fe$$_{17}$$ intermetallic compound

Cao, 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:0 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 Ho$$_2$$Fe$$_{17}$$ 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.

Journal Articles

Ferroaxial transitions in glaserite-type compounds; Database screening, phonon calculations, and experimental verification

Yamagishi, Shigetada*; Hayashida, Takeshi*; Misawa, Ryusuke*; Kimura, Kenta*; Hagihara, Masato; Murata, Tomoki*; Hirose, Sakyo*; Kimura, Tsuyoshi*

Chemistry of Materials, 35(2), p.747 - 754, 2023/01

 Times Cited Count:2 Percentile:93.17(Chemistry, Physical)

Journal Articles

Repeatable photoinduced insulator-to-metal transition in yttrium oxyhydride epitaxial thin films

Komatsu, Yuya*; Shimizu, Ryota*; Sato, Ryuhei*; Wilde, M.*; Nishio, Kazunori*; Katase, Takayoshi*; Matsumura, Daiju; Saito, Hiroyuki*; Miyauchi, Masahiro*; Adelman, J. R.*; et al.

Chemistry of Materials, 34(8), p.3616 - 3623, 2022/04

 Times Cited Count:6 Percentile:73.76(Chemistry, Physical)

Journal Articles

Correlated Li-ion migration in the superionic conductor Li$$_{10}$$GeP$$_{2}$$S$$_{12}$$

Yajima, Takeshi*; Hinuma, Yoyo*; Hori, Satoshi*; Iwasaki, Rui*; Kanno, Ryoji*; Ohara, Takashi; Nakao, Akiko*; Munakata, Koji*; Hiroi, Zenji*

Journal of Materials Chemistry A, 9(18), p.11278 - 11284, 2021/05

 Times Cited Count:15 Percentile:81.41(Chemistry, Physical)

Journal Articles

High oxide-ion conductivity in Si-deficient La$$_{9.565}$$(Si$$_{5.826}$$[]$$_{0.174}$$)O$$_{26}$$ apatite without interstitial oxygens due to the overbonded channel oxygens

Fujii, Kotaro*; Yashima, Masatomo*; Hibino, Keisuke*; Shiraiwa, Masahiro*; Fukuda, Koichiro*; Nakayama, Susumu*; Ishizawa, Nobuo*; Hanashima, Takayasu*; Ohara, Takashi

Journal of Materials Chemistry A, 6(23), p.10835 - 10846, 2018/06

 Times Cited Count:24 Percentile:70.61(Chemistry, Physical)

Journal Articles

Poly(ether ether ketone) (PEEK)-based graft-type polymer electrolyte membranes having high crystallinity for high conducting and mechanical properties under various humidified conditions

Hamada, Takashi; Hasegawa, Shin; Fukasawa, Hideyuki*; Sawada, Shinichi; Koshikawa, Hiroshi; Miyashita, Atsumi; Maekawa, Yasunari

Journal of Materials Chemistry A, 3(42), p.20983 - 20991, 2015/11

 Times Cited Count:32 Percentile:70.95(Chemistry, Physical)

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:26 Percentile:62.78(Chemistry, Physical)

no abstracts in English

Journal Articles

Mechanistic studies on lithium intercalation in a lithium-rich layered material using Li$$_{2}$$RuO$$_{3}$$ epitaxial film electrodes and ${{it in situ}}$ surface X-ray analysis

Taminato, So*; Hirayama, Masaaki*; Suzuki, Kota*; Kim, K.-S.*; Zheng, Y.*; Tamura, Kazuhisa; Mizuki, Junichiro; Kanno, Ryoji*

Journal of Materials Chemistry A, 2(34), p.17875 - 17882, 2014/11

 Times Cited Count:20 Percentile:55.66(Chemistry, Physical)

The surface structure of a lithium-rich layered material and its relation to intercalation properties were investigated by synchrotron X-ray surface structural analyses using Li$$_{2}$$RuO$$_{3}$$ epitaxial-film model electrodes with different lattice planes of (010) and (001). Electrochemical charge-discharge measurements confirmed reversible lithium intercalation activity through both planes, corresponding to three-dimensional lithium diffusion within the Li$$_{2}$$RuO$$_{3}$$. The (001) plane exhibited higher discharge capacities compared to the (010) plane under high rate operation (over 5 C). Direct observations of surface structural changes by ${{it in situ}}$ surface X-ray diffraction (XRD) and surface X-ray absorption near edge structure (XANES) established that an irreversible phase change occurs at the (010) surface during the first (de)intercalation process, whereas reversible structural changes take place at the (001) surface.

Journal Articles

Spin orientation transition across the single-layer graphene/nickel thin film interface

Matsumoto, Yoshihiro; Entani, Shiro; Koide, Akihiro*; Otomo, Manabu; Avramov, P.; Naramoto, Hiroshi*; Amemiya, Kenta*; Fujikawa, Takashi*; Sakai, Seiji

Journal of Materials Chemistry C, 1(35), p.5533 - 5537, 2013/09

 Times Cited Count:32 Percentile:77.13(Materials Science, Multidisciplinary)

Journal Articles

Pressure effect on intersite charge transfer in A-site-ordered double-perovskite-structure oxide

Long, Y.-W.*; Kawakami, Takateru*; Chen, W.-T.*; Saito, Takashi*; Watanuki, Tetsu; Nakakura, Yuta*; Liu, Q.-Q.*; Jin, C.-Q.*; Shimakawa, Yuichi*

Chemistry of Materials, 24(11), p.2235 - 2239, 2012/06

 Times Cited Count:35 Percentile:70.92(Chemistry, Physical)

An A-site ordered perovskite-structure oxide, LaCu$$_{3}$$Fe$$_{4}$$O$$_{12}$$, shows unusual intermetallic charge transfer between the A-site Cu and the B-site Fe ions. Like temperature, pressure also induces the intermetallic charge transfer at room temperature and the compound changes from low-pressure LaCu$$^{3+}$$$$_{3}$$Fe$$^{3+}$$$$_{4}$$O$$_{12}$$ to high-pressure LaCu$$^{2+}$$$$_{3}$$Fe$$^{3.75+}$$$$_{4}$$O$$_{12}$$ accompanying with significant volume collapse and as well as unusual softening in bulk modulus. In addition, the material was changed from an antiferromagnetic insulator to a paramagnetic metal transition. Either by physical or chemical (cation substitution) pressure, the charge-transfer transition temperature decreases, and the lower volume phase stabilizes Cu$$^{2+}$$ and Fe$$^{3.75+}$$ at the A and B sites, respectively.

Journal Articles

Control of epitaxy of graphene by crystallographic orientation of a Si substrate toward device applications

Fukidome, Hirokazu*; Takahashi, Ryota*; Abe, Shunsuke*; Imaizumi, Kei*; Handa, Hiroyuki*; Kang, H. C.*; Karasawa, Hiromi*; Suemitsu, Tetsuya*; Otsuji, Taiichi*; Enta, Yoshiharu*; et al.

Journal of Materials Chemistry, 21(43), p.17242 - 17248, 2011/11

 Times Cited Count:28 Percentile:63.49(Chemistry, Physical)

Journal Articles

Topotactic synthesis and crystal structure of a highly fluorinated Ruddlesden-Popper-type iron oxide, Sr$$_{3}$$Fe$$_{2}$$O$$_{5+x}$$F$$_{2-x}$$ (x $${approx}$$ 0.44)

Tsujimoto, Yoshihiro*; Yamaura, Kazunari*; Hayashi, Naoaki*; Kodama, Katsuaki; Igawa, Naoki; Matsushita, Yoshitaka*; Katsuya, Yoshio*; Shirako, Yuichi*; Akaogi, Masaki*; Muromachi, Eiji*

Chemistry of Materials, 23(16), p.3652 - 3658, 2011/08

 Times Cited Count:24 Percentile:60.06(Chemistry, Physical)

Topotactic reaction of the Ruddlesden-Popper phase Sr$$_{3}$$Fe$$_{2}$$O$$_{7-delta}$$ ($$delta$$ $${approx}$$ 0.18) with polytetrafluoroethylene yields a highly fluorinated phase Sr$$_{3}$$Fe$$_{2}$$O$$_{5+x}$$F$$_{2-x}$$ (x $${approx}$$ 0.44), compared with Sr$$_{3}$$Fe$$_{2}$$O$$_{6}$$F$$_{0.87}$$ prepared by the reaction of Sr$$_{3}$$Fe$$_{2}$$O$$_{6}$$ and F$$_{2}$$ gas. Structure analyses based on powder neutron diffraction, synchrotron powder diffraction, and $$^{57}$$Fe M$"o$ssbauer spectroscopy measurements demonstrate that the new oxyfluoride perovskite has no anion deficiencies and adopts the tetragonal structure (space group ${it I}$4/${it mmm}$) with lattice constants ${it a}$ = 3.87264(6) ${AA}$ and ${it c}$ = 21.3465(6) ${AA}$ at room temperature. The fluoride ions preferentially occupy the terminal apical anion sites with oxide ions in a disordered manner, which results in square pyramidal coordination around iron.

Journal Articles

Degradation manner of polymer grafts chemically attached on thermally stable polymer films; Swelling-induced detachment of hydrophilic grafts from hydrophobic polymer substrates in aqueous media

Enomoto, Kazuyuki*; Takahashi, Shuichi*; Iwase, Takanori*; Yamashita, Takashi*; Maekawa, Yasunari

Journal of Materials Chemistry, 21(25), p.9343 - 9349, 2011/07

 Times Cited Count:37 Percentile:71.74(Chemistry, Physical)

The degradation manner of graft-type polymer electrolyte membranes consisting of hydrophilic poly(styrenesulfonic acid) (PSSA) graft polymers (grafts) and thermally and mechanically stable hydrophobic polymer substrates was examined in hot water. Severe weight loss was observed in PSSA-grafted cPTFE and ETFE films but not in a PSSA-grafted PEEK film. The decomposed extracts in water were characterized as PSSA during the whole course of degradation, clearly showing that the PSSA grafts detached from the fluorinated substrates without decomposition or scission of graft polymer chains. This is quite a new degradation manner for graft-type polymer electrolyte membranes; namely, hydrophilic PSSA grafts detach from hydrophobic polymer substrates due to swelling-induced stress at the interfacial boundary in the grafted films.

Journal Articles

Densified low-hygroscopic form of P$$_{2}$$O$$_{5}$$ glass

Brazhkin, V. V.*; Akola, J.*; Katayama, Yoshinori; Kohara, Shinji*; Kondrin, M. V.*; Lyapin, A. G.*; Lyapin, S. G.*; Tricot, G.*; Yagafarov, O.

Journal of Materials Chemistry, 21(28), p.10442 - 10447, 2011/07

 Times Cited Count:16 Percentile:46.21(Chemistry, Physical)

P$$_{2}$$O$$_{5}$$ compound is an archetypical glass-forming oxide with a high hygroscopicity. We found that the quenching from the P$$_{2}$$O$$_{5}$$melt under ultrahigh pressures enables obtaining densified P$$_{2}$$O$$_{5}$$ glasses with a residual densification up to 12% at normal conditions. These glasses have a low hygroscopicity and can exist under air conditions for several weeks. An examination of the structure of the new form of P$$_{2}$$O$$_{5}$$ glass reveals a cardinal decrease of the volume of nanovoids in the glassy matrix.

Journal Articles

On the role of polymer chains in transducing external mechanical forces to benzocyclobutene mechanophores

Dopieralski, P.*; Anjukandi, P.*; R$"u$ckert, M.*; Shiga, Motoyuki; Ribas-Arino, J.*; Marx, D.*

Journal of Materials Chemistry, 21(23), p.8309 - 8316, 2011/06

The role played by polyethylene-like oligomers in transducing external tensile forces to benzo-cyclobutene mechanophores is investigated computationally. It is demonstrated that the oligomerchains do indeed exert a notable influence on the force-dependence of the activation energies of bothconrotatory and disrotatory ring-opening processes of a $$cis$$ 1,2-disubstituted benzocyclobutene. This opens the doorway to tuning the properties of mechanoresponsive materials not only bychanging the properties of the mechanophore itself, but also by tailoring the force-transducing chain molecules attached to it. Furthermore, it is found that these chains even have a profound impact on the topology of the force-transformed potential energy surface in the vicinity of conrotatory transition states. Hitherto unexpected and most striking is the phenomenon that some of these conrotatory transition states are found to drive the system to disrotatory products.

Journal Articles

On the role of polymer chains in transducing external mechanical forces to benzocyclobutene mechanophores

Dopieralski, P.*; Anjukandi, P.*; R$"u$ckert, M.*; Shiga, Motoyuki; Ribas-Arino, J.*; Marx, D.*

Journal of Materials Chemistry, 21(23), p.8309 - 8316, 2011/06

 Times Cited Count:49 Percentile:79(Chemistry, Physical)

The role played by polyethylene-like oligomers in transducing external tensile forces to benzocyclobutene mechanophores is investigated computationally. It is demonstrated that the oligomer chains do indeed exert a notable influence on the force dependence of the activation energies of both conrotatory and disrotatory ring-opening processes of a cis 1,2-disubstitutedbenzocyclobutene. This opens the doorway to tuning the properties of mechanoresponsive materials not only by changing the properties of the mechanophore itself, but also by tailoring the force-transducing chain molecules attached to it.

Journal Articles

ECP measurements under neutron and $$gamma$$ ray in in-pile loop and their data evaluation by water radiolysis calculations

Hanawa, Satoshi; Nakamura, Takehiko; Uchida, Shunsuke; Kus, P.*; Vsolak, R.*; Kysela, J.*

Proceedings of 2010 Nuclear Plant Chemistry Conference (NPC 2010)/8th International Radiolysis, Electrochemistry & Materials Performance Workshop (CD-ROM), 10 Pages, 2010/10

In order to establish reliable electrochemical corrosion potential (ECP) sensors for applying in reactor core peripherals of power plants, performance tests of sensors under irradiation were carried out in the in-pile loop of the experimental reactor, LVR-15, at the Nuclear Research Institute (NRI) in Czech Republic. Responses of different kinds of sensors under neutron and $$gamma$$ irradiation conditions have been compared each other. Corrosive conditions along the in-pile loop were calculated by water radiolysis calculation code, WRAC-J and calculated corrosive conditions were compared with the measured results. As a result of the evaluation, it was confirmed that the ECP sensors could be applied to irradiation conditions of reactor peripherals, while the water radiolysis model could be also applied for evaluation of corrosive conditions of reactor peripherals.

Journal Articles

ECP evaluation by water radiolysis and ECP model calculations

Hanawa, Satoshi; Nakamura, Takehiko; Uchida, Shunsuke; Kus, P.*; Vsolak, R.*; Kysela, J.*

Proceedings of 2010 Nuclear Plant Chemistry Conference (NPC 2010)/8th International Radiolysis, Electrochemistry & Materials Performance Workshop (CD-ROM), 10 Pages, 2010/10

In-pile ECP measurements data was evaluated by water radiolysis calculations. The data was obtained by using in-pile loop in an experimental reactor, LVR-15, at the Nuclear Research Institute (NRI) in Czech Republic. Three types of ECP sensors, a Pt electrode, an Ag/AgCl sensor and a zirconia membrane sensor containing Ag/Ag$$_{2}$$O were used at several levels of the irradiation rig at various neutron flux and $$gamma$$ rates. Concentration of chemical species along the water flow was calculated by a radiolysis code, WRAC-J. The radiolysis calculation results were transferred to an ECP model. In the model, anodic and cathodic current densities were calculated with combination of an electrochemistry model and an oxide film growth model. The measured ECP data were compared with the radiolysis/ECP calculation results, and applicability of radiolysis model was confirmed.

Journal Articles

Tuning hydrogen production during oxide irradiation through surface grafting

Alam, M.*; Miserque, F.*; Taguchi, Mitsumasa; Boulanger, L.*; Renault, J. P.*

Journal of Materials Chemistry, 19(24), p.4261 - 4267, 2009/06

 Times Cited Count:15 Percentile:44.25(Chemistry, Physical)

The production of molecular hydrogen in the radiolysis with TiO$$_{2}$$ grafted silica has been carefully studied using 10 MeV electrons. In all cases, H$$_{2}$$ yield increases linearly with absorbed dose. Under the irradiation it was observed that with the increasing number of titanium dioxide deposition cycle a decrease in dihydrogen production were observed. A faster decrease in dihydrogen production was observed with a very small amount of titanium dioxide deposition i.e with an average thickness of 0.1 nm as measured by XPS. The productions of H$$_{2}$$ were found to be decreased almost by 50 % with a TiO$$_{2}$$ thickness at around 1 nm.

Journal Articles

Surface structure of LiNi$$_{0.8}$$Co$$_{0.2}$$O$$_{2}$$; A New experimental technique using in situ X-ray diffraction and two-dimensional epitaxial film electrodes

Sakamoto, Kazuyuki*; Hirayama, Masaaki*; Sonoyama, Noriyuki*; Mori, Daisuke*; Yamada, Atsuo*; Tamura, Kazuhisa; Mizuki, Junichiro; Kanno, Ryoji*

Chemistry of Materials, 21(13), p.2632 - 2640, 2009/05

 Times Cited Count:36 Percentile:74.09(Chemistry, Physical)

Surface and bulk structural changes in LiNi$$_{0.8}$$Co$$_{0.2}$$O$$_{2}$$ were observed during electrochemical reactions using synchrotron X-ray scattering and a restricted reaction plane of two-dimensional (2D) epitaxial-film electrodes. The bulk structural changes confirmed lithium diffusion through the (110) surface, which is perpendicular to the 2D edges of the layered structure. No (de)intercalation reaction was observed through the (003) surface in the voltage range of 3.0-5.0 V. However, intercalation proceeded below 3.0 V, which indicates unusual three-dimensional lithium diffusion in the 2D structure in the overlithiated state. Structural changes at the electrode surface were different from those in the bulk.

31 (Records 1-20 displayed on this page)