Unusual Strong Incommensurate Modulation in a Tungsten-Bronze-Type Relaxor PbBiNb5O15

Kun Lin, Zhengyang Zhou, Laijun Liu, Hongqiang Ma, Jun Chen, Jinxia Deng, Junliang Sun, Li You, Hidetaka Kasai, Kenichi Kato, Masaki Takata, Xianran Xing

    Research output: Contribution to journalArticlepeer-review

    27 Citations (Scopus)

    Abstract

    Pb- or Bi-based perovskite oxides have been widely studied and used because of their large ferroelectric polarization features induced by stereochemically active 6s2 lone pair electrons. It is intriguing whether this effect could exist in other related systems. Herein, we designed and synthesized a mixed Pb and Bi A site polar compound, PbBiNb5O15, with the TTB framework. The as-synthesized material turns out to be a relaxor with weak macroscopic ferroelectricity but adopts strong local polarizations. Whats more, unusual five orders of incommensurate satellite reflections with strong intensities were observed under the electron diffraction, suggesting that the modulation is highly developed with large amplitudes. The structural modulation was solved with a (3 + 1)D superspace group using high-resolution synchrotron radiation combined with anomalous dispersion X-ray diffraction technique to distinguish Pb from Bi. We show that the strong modulation mainly originates from lone-pair driven Pb2+-Bi3+ ordering in the large pentagonal caves, which can suppress the local polarization in x-y plane in long ranges. Moreover, the as-synthesized ceramics display strong relaxor ferroelectric feature with transition temperature near room temperature and moderate dielectric properties, which could be functionalized to be electromechanical device materials.

    Original languageEnglish
    Pages (from-to)13468-13471
    Number of pages4
    JournalJournal of the American Chemical Society
    Volume137
    Issue number42
    DOIs
    Publication statusPublished - 2015 Oct 28

    ASJC Scopus subject areas

    • Catalysis
    • Chemistry(all)
    • Biochemistry
    • Colloid and Surface Chemistry

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