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Journal Articles

Origin of magnetovolume effect in a cobaltite

Miao, P.*; Tan, Z.*; Lee, S. H.*; Ishikawa, Yoshihisa*; Torii, Shuki*; Yonemura, Masao*; Koda, Akihiro*; Komatsu, Kazuki*; Machida, Shinichi*; Sano, Asami; et al.

Physical Review B, 103(9), p.094302_1 - 094302_18, 2021/03

https://doi.org/10.1103/PhysRevB.103.094302

Times Cited Count：2 Percentile：17.84(Materials Science, Multidisciplinary)

The layered perovskite PrBaCo $_{2}$ O $_{5.5}$ demonstrates a strong negative thermal expansion (NTE) which holds potential for being fabricated into composites with zero thermal expansion. The NTE was found to be intimately associated with the spontaneous magnetic ordering, known as magneto-volume effect (MVE). Here we report with compelling evidences that the continuous-like MVE in PrBaCo $_{2}$ O $_{5.5}$ is intrinsically of discontinuous character, originating from an magnetoelectric transition from an antiferromagnetic insulating large-volume (AFILV) phase to a ferromagnetic less-insulating small-volume (FLISV) phase. Furthermore, the magnetoelectric effect (ME) shows high sensitivity to multiple external stimuli such as temperature, carrier doping, hydrostatic pressure, magnetic field etc. In contrast to the well-known ME such as colossal magnetoresistance and multi-ferroic effect which involve symmetry breaking of crystal structure, the ME in the cobaltite is purely isostructural. Our discovery provides a new path way to realizing the ME as well as the NTE, which may find applications in new techniques.

Journal Articles

Electrode properties of Li $_{2}$ MnO $_{3}$ (2/) for a lithium-battery cathode in several charge-discharge potential ranges

Nakao, Yasuhiro*; Ozawa, Kiyoshi*; Fujii, Hiroki*; Mochiku, Takashi*; Iwai, Hideo*; Tsuchiya, Yoshinori*; Igawa, Naoki

Transactions of the Materials Research Society of Japan, 38(2), p.229 - 233, 2013/12

https://doi.org/10.14723/tmrsj.38.229

Li $_{2}$ MnO $_{3}$ powder with a monoclinic cell related to the space group of 2/ was synthesized by a simplified coprecipitation method. Its electrode properties as a lithium-battery cathode were investigated in the charge-discharge potential ranges of 2.0 - 4.6, 2.0 - 4.8, and 2.0 - 5.0 V. In all the potential ranges, the electrochemical capacities gradually increased during cycling, and the increased capacities significantly depended on the potential ranges. Compared to the discharge capacities for the potential ranges of 2.0 - 4.6 and 2.0 - 5.0 V, the former merely increased from 12.5 to 22.5 mAhg $^{-1}$ between the 1st and 99th cycles, whereas the latter increased from 20.0 to 110.2 mAhg $^{-1}$ during the same cycling. The structural variation in Li $_{2}$ MnO $_{3}$ is induced by the cycling, the rhombohedral phase is detected during cycling in the potential range of 2.0 - 5.0 V.

Journal Articles

Electrochemical characteristics of layered Li $_{1.95}$ Mn $_{0.9}$ Co $_{0.15}$ O $_{3}$ (2/) as a lithium-battery cathode

Ozawa, Kiyoshi*; Nakao, Yasuhiro*; Mochiku, Takashi*; Cheng, Z.*; Wang, L.*; Iwai, Hideo*; Tsuchiya, Yoshinori*; Fujii, Hiroki*; Igawa, Naoki

Journal of the Electrochemical Society, 159(3), p.A300 - A304, 2012/01

https://doi.org/10.1149/2.079203jes

Times Cited Count：14 Percentile：46.73(Electrochemistry)

A manganese-based solid solution with the composition of Li $_{1.95}$ Mn $_{0.9}$ Co $_{0.15}$ O $_{3}$ was synthesized by a simplified coprecipitation method, and its electrochemical characteristics as a lithium-battery cathode were investigated. Rietveld refinement based on neutron diffraction data revealed that the material is assigned to an Li $_{2}$ MnO $_{3}$ -type structure model with a space group symmetry of 2/. In cycling of the cell in the potential range from 2.0 to 4.8 V at current densities of 30 mAhg $^{-1}$ , the discharge capacity characteristically increases from 46.3 to 196.5 mAhg $^{-1}$ as the cycle increases from 1 to 11, and a discharge capacity above 175.5 mAhg $^{-1}$ is obtained between the 23rd and 58th cycles. The cyclic voltammogram and X-ray photoelectron spectroscopy measurements showed that the manganese redox reaction is progressively activated during the first ten-odd cycles.

Journal Articles

Low temperature structure of FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ magnetic superconductor

Mochiku, Takashi*; Hata, Yoshiaki*; Wuernisha, T.*; Igawa, Naoki; Hoshikawa, Akinori*; Ishigaki, Toru*; Yasuoka, Hiroshi*; Hirata, Kazuto*

Physica C, 470(Suppl.1), p.S158 - S159, 2010/12

https://doi.org/10.1016/j.physc.2009.12.047

Times Cited Count：2 Percentile：12.12(Physics, Applied)

We have performed neutron powder diffraction of the superconducting FeSr $_{2}$ YCu $_{2}$ O $_{6+}$ $_{delta}$ and the nonsuperconducting FeSr $_{2}$ Y(Cu $_{0.95}$ Zn $_{0.05}$ ) $_{2}$ O $_{6+}$ $_{delta}$ samples at low temperature and room temperature to investigate the relation between the crystal structure ant the physical properties. Neutron diffraction study indicates that the magnetic order in this compound is not long-range order because we observed no extra reflection due to the magnetic superstructure. We have observed structural anomaly related to Cu in the superconducting sample around 30 K although we could not observe it in the nonsuperconducting sample. There is possibility of the change of the charge distribution around 30 K in the superconducting sample.

Oral presentation

The Ibaraki prefecture materials design diffractometer for J-PARC

Ishigaki, Toru; Harjo, S.; Yonemura, Masao*; Kamiyama, Takashi*; Mori, Kazuhiro*; Mochiku, Takashi*; Aizawa, Kazuya; Arai, Masatoshi; Ebata, Kazuhiro*; Takano, Yoshiki*

no journal, ,

no abstracts in English

Oral presentation

Present status for Ibaraki materials design diffractometer

Ishigaki, Toru; Hoshikawa, Akinori; Yonemura, Masao*; Kamiyama, Takashi*; Mori, Kazuhiro*; Mochiku, Takashi*; Aizawa, Kazuya; Arai, Masatoshi; Ebata, Kazuhiro*; Takano, Yoshiki*; et al.

no journal, ,

no abstracts in English

Oral presentation

Low temperature structure of FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ magnetic superconductor

Mochiku, Takashi*; Hata, Yoshiaki*; Tuerxun, W.*; Igawa, Naoki; Hoshikawa, Akinori*; Ishigaki, Toru*; Yasuoka, Hiroshi*; Hirata, Kazuto*

no journal, ,

FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ is known as the Ba $_{2}$ YCu $_{3}$ O $_{6+delta}$ related super conducting compound with the substitution of the Fe for Cu, only when it is annealed in reduced atmosphere and subsequently in oxidized atmosphere. In this study, we have performed neutron powder diffraction of FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ to investigate the magnetic disorder-ordering mechanism. No magnetic reflection was observed even below the magnetic transition temperature. This result indicated that the material has not long-range magnetic-ordering.

Oral presentation

Oxygen arrangement in FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ system

Mochiku, Takashi*; Hata, Yoshiaki*; Tsuchiya, Yoshinori*; Igawa, Naoki; Hoshikawa, Akinori*; Ishigaki, Toru*; Yasuoka, Hiroshi*; Hirata, Kazuto*

no journal, ,

FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ structure exhibits superconductivity around 60 K, when it is properly annealed in N $_{2}$ and subsequently in O $_{2}$ . In this study, oxygen arrangement in FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ system is investigated by the neutron diffraction method. Cu and Fe in the crystal were ordered by annealing around 700 $^{circ}$ C in N $_{2}$ due to structure phase transition from the tetragonal to monoclinic phase with a superlattice structure. It was revealed that the FeO $_{4}$ tetrahedron was formed and ordered in the crystal while disordered in the original structure without N $_{2}$ -annealing. It was observed that the FeO $_{4}$ tetrahedron changed to the octahedron by the subsequently annealing in O $_{2}$ .

Oral presentation

Oxygen deficiency in FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ magnetic superconductor

Mochiku, Takashi*; Hata, Yoshiaki*; Tsuchiya, Yoshinori*; Igawa, Naoki; Hoshikawa, Akinori*; Ishigaki, Toru*; Yasuoka, Hiroshi*; Ozawa, Kiyoshi*; Hirata, Kazuto*

no journal, ,

It is well known that the superconductive phase is related with the ordering of Cu and Fe, and with the oxygen deficiency in FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ . We investigated the oxygen deficiency of FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ by neutron diffraction method. It was shown that non superconductor phase was stable around the oxygen content 6+ = 7 and that the superconductive phase was appeared at 7.6 of the oxygen content 6+.

Oral presentation

Disorder and physical properties in FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ magnetic superconductor

Mochiku, Takashi*; Hata, Yoshiaki*; Hoshikawa, Akinori*; Iwase, Kenji*; Sulistyanintyas, D.*; Oguro, Hidetoshi*; Ishigaki, Toru*; Igawa, Naoki; Tsuchiya, Yoshinori*; Iwai, Hideo*; et al.

no journal, ,

FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ is expected to coexhibit superconductivity and magnetism, which has a tetragonal structure with the oxygen defect and the substitution between Cu and Fe. We have performed neutron powder diffraction of the FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ system to investigate the relation between the crystal structure and the physical properties.

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Origin of magnetovolume effect in a cobaltite

Electrode properties of Li $_{2}$ MnO $_{3}$ (2/) for a lithium-battery cathode in several charge-discharge potential ranges

Electrochemical characteristics of layered Li $_{1.95}$ Mn $_{0.9}$ Co $_{0.15}$ O $_{3}$ (2/) as a lithium-battery cathode

Low temperature structure of FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ magnetic superconductor

The Ibaraki prefecture materials design diffractometer for J-PARC

Present status for Ibaraki materials design diffractometer

Low temperature structure of FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ magnetic superconductor

Oxygen arrangement in FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ system

Oxygen deficiency in FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ magnetic superconductor

Disorder and physical properties in FeSr $_{2}$ YCu $_{2}$ O $_{6+delta}$ magnetic superconductor