Structure-property relationships in the lanthanide-substituted PbBi2Nb2O9 Aurivillius phase synthesized by the molten salt method

Tio Putra Wendari, Syukri Arief, Nandang Mufti, Andon Insani, Jacob Baas, Graeme R. Blake, Zulhadjri*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Samples of PbBi2Nb2O9, PbBi1.5La0.5Nb2O9, and PbBi1.5Nd0.5Nb2O9 have been prepared by the molten salt method. The structure, morphology, and electrical properties were investigated. All samples are single-phase and crystallize in an orthorhombic structure with A21am symmetry. Neutron diffraction data indicate that the Ln3+ cations prefer to occupy the perovskite A-site, whereas Pb/Bi occupy the perovskite A-site and the Bi2O2 layer. Changes in unit cell volume are observed on substitution and are attributed to the ionic radii of the Ln3+ cations and also correlated to changes in the B-O bond distances in the BO6 octahedra, which are also observed in IR spectra. SEM images reveal anisotropic plate-like grains, which increase in size with the presence of Ln3+ ions. The ferroelectric transition temperature (Tc) decreases with decreasing degree of BO6 distortion as the influence of the 6s2 lone pair of Bi3+ is diminished. Relaxor ferroelectric behavior is observed with Ln3+ substitution, driven by the disorder of the A-site cations. The room temperature ferroelectric polarization increases with Ln3+ substitution, ascribed to the decreased dielectric loss.

Original languageEnglish
Article number158440
Number of pages9
JournalJournal of Alloys and Compounds
Volume860
DOIs
Publication statusPublished - 15-Apr-2021

Keywords

  • Aurivillius phase
  • Cation disorder
  • Ferroelectric properties
  • Rare-earth substitution
  • Structural analysis

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