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

Zulhadjri, Zulhadjri (2020) Structure-property relationships in the lanthanide-substituted PbBi2Nb2O9 Aurivillius phase synthesized by the molten salt method. Journal of Alloys and Compounds, 860 (-). pp. 1-9. ISSN 0925-8388

Text Artikel Jalco 2021.pdf - Published Version Restricted to Registered users only until 31 December 2022. Download (3MB) | Request a copy

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.

Actions (login required)

View Item