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

Research output: Chapter in Book/Report/Conference proceedingConference 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.

Original languageEnglish
Title of host publicationTHERMEC 2016
EditorsChristof Sommitsch, Mihail Ionescu, Brajendra Mishra, Brajendra Mishra, Ernst Kozeschnik, T. Chandra
PublisherTrans Tech Publications Ltd
Number of pages6
ISBN (Print)9783035711295
Publication statusPublished - 2017
Event9th International Conference on Processing and Manufacturing of Advanced Materials, THERMEC 2016 - Graz, Austria
Duration: 2016 May 292016 Jun 3

Publication series

NameMaterials Science Forum
ISSN (Print)0255-5476
ISSN (Electronic)1662-9752


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


  • BiLaFeO
  • Modulated structure
  • Multiferroic material
  • Transmission electron microscopy

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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