Local Structure Analysis of Lead Zinc Niobate-Barium Titanate Ceramic by X-Ray Absorption Spectroscopy and Density Functional Calculation

Abstract

The local structure of an alternative Pb(Zn1/3Nb2/3)O3-based perovskite ceramic is investigated. The 0.07BaTiO3-0.93Pb(Zn1/3Nb2/3)O3 ceramic is synthesized using a combination of Zn3Nb2O8 B-site precursor and BaTiO3 perovskite phase stabilizer. Then, x-ray absorption spectroscopy and density functional theory are employed to calculate the local structure configuration and formation energy of the prepared samples. Ba2+ is found to replace Pb2+ in A-site with Zn2+ occupying B-site in Pb(Zn1/3Nb2/3)O3, while in the neighboring structure, Ti4+ replaces Nb5+ in B-site with Pb2+ occupying A-site. With the substitution of BaTiO3 in Pb(Zn1/3Nb2/3)O3, the bond length between Zn2+ and Pb2+ is longer than that of the typical perovskite phase of Pb(Zn1/3Nb2/3)O3. This indicates the key role of BaTiO3 in decreasing the steric hindrance of Pb2+ lone pair, and the mutual interactions between Pb2+ lone pair and Zn2+ and the formation energy is seen to decrease. This finding of the formation energy and local structure configuration relationship can further extend a fundamental understanding of the role of BaTiO3 in stabilizing the perovskite phase in PbZn13Nb23O3-based materials, which in turn will lead to an improved preparation technique for desired electrical properties.