研究者詳細 - 堀部　陽一

論文 - 堀部　陽一

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Charged Domain Walls and Crystallographic Microstructures in Hybrid Improper Ferroelectric Ca3-xSrxTi2O7 査読有り

Nakajima Hiroshi, Shigematsu Koji, Horibe Yoichi, Mori Shigeo, Murakami Yasukazu

MATERIALS TRANSACTIONS 2019年07月

記述言語：英語掲載種別：研究論文（学術雑誌）

The charged domain walls in ferroelectric materials exhibit intriguing physical properties. We examine herein the charged-domain-wall structures in Ca3−xSrxTi2O7 using transmission electron microscopy. When viewed along the [001] axis, the wavy charged domain walls are observed over a wide range (>5 µm). In contrast, short charged-domain-wall fragments (from 10 to 200 nm long) occur because they are intercepted and truncated by the conventional 180° domain walls. These results reveal the unusual charged domain structures in Ca3−xSrxTi2O7 and will be useful for understanding their formation process.

DOI： 10.2320/matertrans.MT-MI2019006

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007681964

Effect of Ca doping on modulated structures in multiferroic Bi1-xCaxFeO3 査読有り

Hiroyama T., Hirata A., Inoue Y., Horibe Y., Koyama Y.

Journal of the Physical Society of Japan 88 054601 2019年04月

2.45GHz電磁波を用いたカーボンナノウォールの成長査読有り

青柳佑海人, 藤原孝将, 小椋裕美, 小野裕介, 大久保貴広, 大久保智子, 西川雅仁, 森正和, 堀部陽一, 仁科勇太, 狩野旬, 池田直

日本物理学会講演概要集 ( 一般社団法人日本物理学会 ) 74.1 ( 0 ) 1817 - 1817 2019年01月

マルチフェロイック六方晶マンガン酸化物における特異なドメイン構造　～透過型電子顕微鏡を用いたドメイン観察～査読有り

堀部陽一

セラミックス 54 99 - 102 2019年01月

コールドクルーシブル溶解法で溶製した高純度Fe-3 mass%Si合金の磁気特性と機械的特性査読有り

中川翔太, 渡辺稜介, 佐々木巌, 竹澤昌晃, 堀部陽一, 波多聰, 開道力, 小川俊文, 恵良秀則

日本金属学会誌 82 ( 12 ) 476 - 483 2018年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）

Magnetic properties and mechanical properties of high purity Fe-3 mass%Si alloy by cold crucible levitation melting was investigated. The raw material of the alloy made from electrolytic iron and pure silicon with a purity of 99.99 mass% and 99.999 mass% in amount of impurities excluding Fe and Si were suppressed to 90 ppm or less. In the magnetic property, the iron loss of the alloy was reduced to a third of 35H210, a silicon steel sheet of the same Si composition commercially. This reduction shows the effect of high purity. In the magnetic domain observation, the equal behavior as magnetic properties was observed. In mechanical property, it proved that the high purity Fe-3 mass%Si alloy was easy to draw because the elongation of the alloy was higher than the commercially available silicon steel sheet.

DOI： 10.2320/jinstmet.J2018008

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130007492739

Magnetic properties and crystal structure of high-purity Fe-(6,6.5,7) mass%Si alloys 査読有り

Matsuyama K., Sasaki I., Nakagawa S., Era H., Takezawa M., Horibe Y., Hata S., Kaidou C., Ogawa T., Kubo S.

2018 IEEE International Magnetic Conference, INTERMAG 2018 2018年10月

Transport, magnetic, thermoelectric, and structural properties of hollandite titanates BaxTi8O16+δ 査読有り

Y. Yamashita, T. Okuda, S. Mori, Y. Horibe, R. Murata, and T. Katsufuji

Physical Review Materials 2 074409 2018年08月

遷移金属酸化物における相分離を利用したチェッカーボード型ナノ組織の作製とその特徴招待有り査読有り

堀部陽一, 森茂生

まてりあ 57 ( 6 ) 271 - 276 2018年06月

Peculiar Optical Characteristics of Different Silicate Source and Synthesis Technique in Europium Doped Li<inf>2</inf>SrSiO<inf>4</inf> 査読有り

Woo H., Horibe Y., Jha K., Jang K., Jeong J.

Journal of the Korean Physical Society 72 ( 11 ) 1350 - 1355 2018年06月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2018, The Korean Physical Society. In this work, a silicate based phosphor doped with divalent and trivalent europium (Eu(2+/3+)) ions have been synthesized by two different synthesis processes, PGMS (propylene glycol modified silane) assisted sol-gel and solid state reaction (SSR) method. The structural, morphological and optical properties were studied in detail. The emission intensity of Li2SrSiO4:Eu3+phosphors synthesized through the PGMS assisted sol-gel increased up to 10 times more than that prepared by SSR method. However, Li2SrSiO4:Eu2+phosphor prepared by PGMS exhibited lower emission characteristics and decreased to one-third of that prepared by SSR. The Eu3+doped Li2SrSiO4synthesized by SSR method using different silicate (Si) sources revealed peculiar optical properties and this is the first kind of its report. The obtained results suggest that the optical properties of Eu(3+/2+)doped in silicate host can be regulated by the alteration of Si source besides sample preparation method. These results open a way to understand the mechanisms responsible for such optical properties and to develop new materials for white LEDs.

DOI： 10.3938/jkps.72.1350

Scopus

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Electric property measurement of free-standing SrTiO<inf>3</inf>nanoparticles assembled by dielectrophoresis 査読有り

Budiman F., Kotooka T., Horibe Y., Eguchi M., Tanaka H.

Japanese Journal of Applied Physics 57 ( 6 ) 2018年06月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2018 The Japan Society of Applied Physics. Free-standing strontium titanate (SrTiO3/STO) nanoparticles (NPs) were synthesized by the sol-gel method. X-ray diffractometry revealed that the required minimum annealing temperature to synthesize pure and highly crystalline STO NPs was 500 °C. Moreover, morphological observation by field emission scanning electron microscopy showed that the STO NPs have a spherical structure and their size depended on annealing condition. Electrical properties were measured using a low-temperature probing system. Here, an electrode was fabricated by electron beam lithography and the synthesized STO NPs were aligned at the electrodes by dielectrophoresis. The conductance of a sample was proportional to temperature. Two conduction mechanisms originating from hopping and tunneling appeared in the Arrhenius plot.

DOI： 10.7567/JJAP.57.06HE07

Scopus

CiNii Article

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85047895168&origin=inward

Effect of the size of the particles in a raw SiO<inf>2</inf>material on the optical properties of Eu(2+/3+)-Doped Li<inf>2</inf>SrSiO<inf>4</inf> 査読有り

Kim T., Namkhai P., Jang K., Horibe Y., Woo H.

New Physics: Sae Mulli 68 ( 6 ) 593 - 598 2018年06月

記述言語：英語掲載種別：研究論文（学術雑誌）

© The Korean Physical Society. All rights reserved. Lithium-strontium-silicate phosphors activated with divalent or trivalent europium ions were synthesized through a conventional solid-state reaction method by using SiO2 with micron-size and nanosize particles as a silicate source. The crystal structures are almost the same in the samples prepared with micron size and nanosize SiO2. However, we newly found that the optical properties of Eu(2+/3+)-activated phosphors depended very much on the size of the particles in the raw SiO2 material adopted as the Si source. The maximal emission wavelength of the Eu2+-doped phosphor prepared with the micron-size SiO2 source was also revealed to be shifted to shorter wavelength by 13 nm as compared to that of Eu2+-doped phosphor prepared with a nanosize SiO2 source.

DOI： 10.3938/NPSM.68.593

Scopus

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Size Dependent Magnetic and Electric Properties of Superoxygenated Free Standing La2CuO4 Nanoparticles 査読有り

Budiman Faisal, Horibe Yoichi, Tanaka Hirofumi

応用物理学会学術講演会講演予稿集 ( 公益社団法人応用物理学会 ) 2017.2 ( 0 ) 2817 - 2817 2017年08月

Crystallographic features of the state appearing in the multiferroic material Bi<inf>1-x</inf>La<inf>x</inf>FeO<inf>3</inf> around x = 0 20 査読有り

Yoshida H., Nomoto M., Inoshita T., Inoue Y., Horibe Y., Koyama Y., Koyama Y.

Materials Science Forum 879 2222 - 2227 2017年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

© 2017 Trans Tech Publications, Switzerland.The simple-perovskite system Bi1-xLaxFeO3 (BLFO) is one of mixed-oxide systems having the multiferroic BiFeO3 as an end material, which shows the ferroelectric and antiferromagnetic orders in its ground state. Because of the paraelectric nature of LaFeO3 as another end material, the ferroelectric-to-paraelectric state change can be expected to occur in the mixed-oxide system BLFO. The interesting feature of BLFO is that there are both the PbZrO3-type and incommensurately modulated (IM) states in the intermediate La-content range between the ferroelectric-R3c and paraelectric-Pnma states. Although the detailed features of these two states have not been understood sufficiently, in this study, we focus on the IM state around x = 0.20, and have investigated the crystallographic features of prepared BLFO samples with 0.15 ≤ x ≤ 0.35, mainly by transmission electron microscopy. It was found that six kinds of superlattice reflections were, for instance, present in the reciprocal lattice of the state at 300 K for x = 0.20, in addition to fundamental reflections due to the cubic simple-perovskite structure. To understand the appearance of these superlattice reflections, we regarded the state as a modulated-structure state in this study. Concretely, the modulated structure was assumed to be characterized by the appearance of both the incommensurate wave with qI = <1/(4+δ) 1/(4+δ) 0>c and the commensurate wave with qII = <1/4 0 0>c in the normal-Imma structure. In addition, the appearance of the two modulation waves could also produce the superlattice reflections at the <1/4 1/4 1/4>c-, <1/2 0 0>c-, and <1/2 1/2 0>c-type positions in the reciprocal lattice. From the comparison with the experimental data obtained in this study, our modulated-structure model seems to be appropriate for the IM state in the vicinity of the PbZrO3-type/IM state boundary.

DOI： 10.4028/www.scientific.net/MSF.879.2222

Scopus

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Characteristic features of the modulated structure appearing in the multiferroic material Bi<inf>1-x</inf>Sm<inf>x</inf>FeO<inf>3</inf> around x = 0.15 査読有り

Nomoto M., Inoshita T., Inoue Y., Horibe Y., Koyama Y., Koyama Y.

Materials Science Forum 879 1393 - 1398 2017年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

© 2017 Trans Tech Publications, Switzerland.In Bi1-xSmxFeO3 (BSFO) having the multiferroic BiFeO3 as an end material, when the Sm content increases from x = 0, it has been reported that the ferroelectric-R3c state is changed into the paraelectric-Pnma state around x = 0.14. The R3c/Pnma state boundary around x = 0.14 can be regarded as a temperature-independent morphotropic-phase boundary (MPB). The notable feature in BSFO is that, in addition to these two states, the antiferroelectric PbZrO3-type state was also found in the vicinity of the MPB. Although the PbZrO3-type state appears as a modulated structure, its detailed features have not been understood yet. We have thus examined the crystallographic features of prepared BSFO samples around x = 0.14, mainly by transmission electron microscopy. The PbZrO3-type state was confirmed to be present in samples with x = 0.15 on the basis of x-ray powder diffraction profiles measured from prepared samples at 300 K. On the other hand, the observation made by transmission electron microscopy indicated that the state for x = 0.15 is characterized by a coexistence state consisting of the ferroelectric-R3c and antiferroelectric PbZrO3-type states. In particular, the crystal structure of the PbZrO3-type state could be identified as a modulated structure with two transverse modulation waves, whose wave vectors are given by qi = [1/2 0 0]o and q2 = [0 1/2 0]o in the orthorhombic-Pnma notation. In addition, eigenvectors of these two transverse waves were also determined to be parallel to the same [001]o direction.

DOI： 10.4028/www.scientific.net/MSF.879.1393

Scopus

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Large-scale phase separation with nano-twin domains in manganite spinel (Co,Fe,Mn)<inf>3</inf>O<inf>4</inf> 査読有り

Horibe Y., Takeyama S., Mori S.

AIP Conference Proceedings 1763 2016年08月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

© 2016 Author(s).The effect of Mn concentration on the formation of nano-domain structures in the spinel oxide (Co,Fe,Mn)3O4 was investigated by electron diffraction, bright-, and dark-field imaging technique with transmission electron microscopy. Large scale phase separation with nano-twin domains was observed in Co0.6Fe1.0Mn1.4O4, in contrast to the highly aligned checkerboard nano-domains in Co0.6Fe0.9Mn1.5O4. Diffusion of the Mn3+ ions with the Jahn-Teller distortions is suggested to play an important role in the formation of checkerboard nano-domain structure.

DOI： 10.1063/1.4961358

Scopus

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Features of the ferroelectric domain structure in the multiferroic material YbMnO<inf>3</inf> 査読有り

Inoshita T., Inoue Y., Horibe Y., Koyama Y.

MRS Advances 1 ( 9 ) 591 - 596 2016年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

© 2016 Materials Research Society. The multiferroic material YbMnO3 has been reported to exhibit both ferroelectric and antiferromagnetic orders in the ground state. Of these two orders, the ferroelectric order is associated with the P63/mmc-to-P63cm structural transition, which occurs around 1270 K. The interesting feature of the ferroelectric state is that a cloverleaf domain structure with a pseudo-six-fold symmetry is observed in transmission electron microscopy images with the beam incidence parallel to the hexagonal axis. To understand the origin of the formation of the cloverleaf domain structure, we have examined the crystallographic features of the ferroelectric state in YbMnO3 by transmission electron microscopy. In this study, particularly, we adopted the experimental condition that electron beam incidences are perpendicular to the hexagonal axis. It was, as a result, found that there existed various ferroelectric domain structures including the cloverleaf domain structure under the present condition. The notable feature of domain structures found in this study is that each domain structure basically consists of six domains, whose domain boundaries are terminated at one point. Because this feature makes us reminiscent of a discommensurate structure in an incommensurate state, we took high-resolution electron micrographs of areas including domain boundaries. Their analysis indicated that a domain boundary could be identified as a discommensuration with a phase slip of π/3. It is thus understood that the cloverleaf domain structure should be one of domain morphologies for a discommensurate structure, which is related to the break of the translational symmetry.

DOI： 10.1557/adv.2016.154

Scopus

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Crystallographic features in the vicinity of the morphotropic phase boundary in the multiferroic material Bi<inf>1-x</inf>Sm<inf>x</inf>FeO<inf>3</inf> 査読有り

Nomoto M., Inoshita T., Inoue Y., Horibe Y., Koyama Y.

MRS Advances 1 ( 9 ) 573 - 578 2016年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

© 2016 Materials Research Society. The multiferroic material Bi 1-x Sm xFeO 3 shows ferroelectric and antiferromagnetic properties in the ground state of the Bi-rich side. When the Sm content increases from x = 0 in BiFeO 3 , the (ferroelectric-R3c → paraelectric-Pnma) state change occurs around x = 0.14. According to the previous studies on Bi 1-x Sm xFeO 3 , the state boundary between the R3c and Pnma states can be identified as a morphotropic phase boundary (MPB), which is nearly parallel to the temperature axis in the state diagram. The notable feature of Bi 1-x Sm xFeO 3 is that a remarkable piezoelectric response was also found near the MPB. However, the origin of the remarkable response has not been understood sufficiently. In this study, thus, the crystallographic features in the vicinity of the MPB have been examined by x-ray powder diffraction and transmission electron microscopy. It was confirmed that the R3c and Pnma states were present for 0 ≤ x ≤ 0.15 and for 0.16 ≤ x ≤ 0.30, respectively. In addition to these states, there also existed the PbZrO 3 -type state around x = 0.15, which was identified as a modulated structure. Based on the analysis of the modulated structure, furthermore, it was suggested that the PbZrO 3 -type state could be regarded as a 2q state, which is characterized by two transverse modulation waves with k1 = [1/2 0 0]o and k2 = [0 1/2 0] o in the orthorhombic-Pnma notation.

DOI： 10.1557/adv.2016.155

Scopus

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特集「顕微鏡法による材料開発のための微細構造研究最前線(10)」—顕微鏡イメージング技術の進展と材料科学の新展開— 企画にあたって査読有り

佐藤和久, 赤瀬善太郎, 佐藤幸生, 千星聡, 高橋淳, 垂水竜一, 堀部陽一, 本間智之

まてりあ ( 公益社団法人日本金属学会 ) 55 ( 12 ) 575 - 575 2016年01月

Electronic phase transition in hollandite titanates BaxTi8O16+δ 査読有り

R. Murata, T. Sato, T. Okuda, Y. Horibe, H. Tsukasaki, S. Mori, N. Yamaguchi, K. Sugimoto, S. Kawaguchi, M. Takata, and T. Katsufuji

Physical Review B 92 220408 (R) 2015年12月

The hysteresis properties analysis of Fe-4 wt% Si prepared by high purity metallurgy 査読有り

Z. Lei, T. Horiuchi, I. Sasaki, C. Kaido, M. Takezawa, S. Hata, Y. Horibe, T. Ogawa, and H. Era

Journal of the Magnetics Society of Japan 40 8 - 12 2015年12月

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