Existence of local polar domains in perovskite oxyfluoride, BaFeOF

Katsumata, Tetsuhiro*; Suzuki, Ryo*; Sato, Naoto*; Oda, Ryoya*; Motoyama, Shingo*; Suzuki, Shumpei*; Nakashima, Mamoru*; Inaguma, Yoshiyuki*; Mori, Daisuke*; Aimi, Akihisa*; et al.

Chemistry of Materials, 36(8), p.3697 - 3704, 2024/04

https://doi.org/10.1021/acs.chemmater.3c03275

A perovskite-type oxynitride BaFeOF was prepared by high-pressure synthesis. Since the SHG signal was observed in the obtained material, suggesting the existence of spontaneous polarization, the mechanism of polarization was investigated by synchrotron high-energy X-ray diffraction. The obtained pair distribution functions were fitted, and a local polarization mechanism with different orientations was found. Since BaFeOF is also a magnetic material, a magnetic domain and a ferroelectric domain are considered to coexist.

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

https://doi.org/10.1021/acs.chemmater.2c03540

Correlated Li-ion migration in the superionic conductor LiGePS

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

https://doi.org/10.1039/D1TA00552A

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

https://doi.org/10.1039/C5TA05567A

no abstracts in English

Mechanistic studies on lithium intercalation in a lithium-rich layered material using LiRuO epitaxial film electrodes and 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

https://doi.org/10.1039/C4TA02795G

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 LiRuO 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 LiRuO. 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 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.

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

https://doi.org/10.1021/cm301267e

An A-site ordered perovskite-structure oxide, LaCuFeO, 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 LaCuFeO to high-pressure LaCuFeO 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 and Fe at the A and B sites, respectively.

Topotactic synthesis and crystal structure of a highly fluorinated Ruddlesden-Popper-type iron oxide, SrFeOF (x 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

https://doi.org/10.1021/cm201075g

Topotactic reaction of the Ruddlesden-Popper phase SrFeO ( 0.18) with polytetrafluoroethylene yields a highly fluorinated phase SrFeOF (x 0.44), compared with SrFeOF prepared by the reaction of SrFeO and F gas. Structure analyses based on powder neutron diffraction, synchrotron powder diffraction, and Fe Mssbauer spectroscopy measurements demonstrate that the new oxyfluoride perovskite has no anion deficiencies and adopts the tetragonal structure (space group 4/) with lattice constants = 3.87264(6) and = 21.3465(6) 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.

Densified low-hygroscopic form of PO 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

https://doi.org/10.1039/c1jm10889a

PO compound is an archetypical glass-forming oxide with a high hygroscopicity. We found that the quenching from the POmelt under ultrahigh pressures enables obtaining densified PO 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 PO glass reveals a cardinal decrease of the volume of nanovoids in the glassy matrix.

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

Dopieralski, P.*; Anjukandi, P.*; Rckert, M.*; Shiga, Motoyuki; Ribas-Arino, J.*; Marx, D.*

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

https://doi.org/10.1039/c0jm03698f

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 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.

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/AgO were used at several levels of the irradiation rig at various neutron flux and 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.