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

  • The local structure of an alternative Pb(Zn_1/3Nb_2/3)O_3-based perovskite ceramic is investigated. The 0.07BaTiO_3-0.93Pb(Zn_1/3Nb_2/3)O_3 ceramic is synthesized using a combination of Zn_3Nb_2O_8 B-site precursor and BaTiO_3 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. Ba^2+ is found to replace Pb^2+ in A-site with Zn^2+ occupying B-site in Pb(Zn_1/3Nb_2/3)O_3, while in the neighboring structure, Ti^4+ replaces Nb^5+ in B-site with Pb^2+ occupying A-site. With the substitution of BaTiO_3 in Pb(Zn_1/3Nb_2/3)O_3, the bond length between Zn^2+ and Pb^2+ is longer than that of the typical perovskite phase of Pb(Zn_1/3Nb_2/3)O_3. This indicates the key role of BaTiO_3 in decreasing the steric hindrance of Pb^2+ lone pair, and the mutual interactions between Pb^2+ lone pair and Zn^2+ 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 BaTiO_3 in stabilizing the perovskite phase in PbZn_13Nb_23O_3-based materials, which in turn will lead to an improved preparation technique for desired electrical properties.
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