Synthesis, structure, and properties of solid solutions based on bismuth ferrite

Abstract

Solid solutions of Bi1 − x Pb x Fe1 − x Zr x O3 (x = 0.1−0.2) are synthesized by the methods of liquid-phase and modified solid-phase synthesis. Also, solid solutions of [Bi0.9(Pb0.9Ln0.1)0.1][Fe0.9(Zr0.65Ti0.35)0.1]O3, and [Bi0.9(Pb0.9Ln0.1)0.1][Fe0.9(Zr0.53Ti0.47)0.1]O3 (Ln - La, Pr, Gd, Yb) are made, including synthesis of their precursors with organic ligands. Comprehensive investigations involving thermal analysis, IR spectroscopy, X-ray powder diffraction, atomic force microscopy, dielectric and magnetic measurements, and neutron powder diffraction are performed. The full-profile analysis of X-ray and neutron diffraction patterns by the Rietveld method shows that, over the whole temperature interval of 10–700 K under study, the Bi0.9Pb0.1Fe0.9Zr0.1O3 and Bi0.8Pb0.2Fe0.8Zr0.2O3 compounds are characterized by the perovskite structure (space group R3c). The magnetic measurements reveal an antiferromagnetic phase transition in the Bi0.9Pb0.1Fe0.9Zr0.1O3 and Bi0.8Pb0.2Fe0.8Zr0.2O3 solid solutions. The Neel temperature (T N ) decreases considerably with growing PbZrO3 concentration as compared to the Neel point in pure BiFeO3 (T N = 633 K). The perovskite structure with a hexagonal distortion is found in lanthanide-substituted solid solutions and specific features of the surface morphology of the ceramics are analyzed. The magnetic measurements suggest the presence of an antiferromagnetic phase transition in the solid solutions under study, with a considerable drop of T N in the Ln-alloyed compound as compared to the T N value in pure BiFeO3