Crystallographic features of the state appearing in the multiferroic material Bi1-xLaxFeO3 around x = 0 20

Haruka Yoshida, Masashi Nomoto, Takumi Inoshita, Yasuhide Inoue, Yoichi Horibe, Yasumasa Koyama

研究成果: Conference contribution


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.

ホスト出版物のタイトルTHERMEC 2016
編集者Christof Sommitsch, Mihail Ionescu, Brajendra Mishra, Brajendra Mishra, Ernst Kozeschnik, T. Chandra
出版社Trans Tech Publications Ltd
出版ステータスPublished - 2017
イベント9th International Conference on Processing and Manufacturing of Advanced Materials, THERMEC 2016 - Graz, Austria
継続期間: 2016 5 292016 6 3


名前Materials Science Forum


Other9th International Conference on Processing and Manufacturing of Advanced Materials, THERMEC 2016

ASJC Scopus subject areas

  • 材料科学(全般)
  • 凝縮系物理学
  • 材料力学
  • 機械工学


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