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

• DOI: 10.1021/jacs.5b08230
• Publication Date: 2015-10-16T14:02:05Z
• Authors: Kun Lin; Zhengyang Zhou; Laijun Liu; Hongqiang Ma; Jun Chen; Jinxia Deng; Junliang Sun; Li You; Hidetaka Kasai; Kenichi Kato; Masaki Takata; Xianran Xing
• Keywords: Bronze; Modulation (music)

Pb- or Bi-based perovskite oxides have been widely studied and used because of their large ferroelectric polarization features induced by stereochemically active 6s(2) lone pair electrons. It is intriguing whether this effect could exist in other related systems. Herein, we designed synthesized a mixed Pb Bi A site polar compound, PbBiNb5O15, with the TTB framework. The as-synthesized material turns out to be relaxor weak macroscopic ferroelectricity but adopts strong local polarizations. What's more, unusual five orders incommensurate satellite reflections intensities were observed under electron diffraction, suggesting that modulation highly developed amplitudes. structural was solved (3 + 1)D superspace group using high-resolution synchrotron radiation combined anomalous dispersion X-ray diffraction technique distinguish from Bi. We show mainly originates lone-pair driven Pb(2+)-Bi(3+) ordering pentagonal caves, which can suppress x-y plane long ranges. Moreover, ceramics display feature transition temperature near room moderate dielectric properties, functionalized electromechanical device materials.