Synthesis and structural characterization of a novel perovskite oxyfluoride BaY0.5Zr0.5O2.5F0.5

Abstract

In this study, a novel perovskite oxyfluoride BaY0.5Zr0.5O2.5F0.5 was prepared by a solid-state reaction using BaCO3, ZrO2, Y2O3 and BaF2 as raw materials. The synthetic process of BaY0.5Zr0.5O2.5F0.5, the effect of the mole ratio of raw materials, and sintering temperature on the phase composition were investigated, and the structure of BaY0.5Zr0.5O2.5F0.5 was characterized. The results indicated that the pure oxyfluoride compound BaY0.5Zr0.5O2.5F0.5 was successfully synthesized after sintering at 1400 °C for 24 h with 15% mol excess BaF2. The grains of BaY0.5Zr0.5O2.5F0.5 were of a regular columnar shape with a size of 0.5–2 μm. The space group of BaY0.5Zr0.5O2.5F0.5 was Pm-3m with a = 4.2819 Å. In this simple perovskite structure, Ba atoms occupied the body center of the structure, Y and Zr atoms were disordered in the B site, and O and F atoms were disordered in the X site, with the occupation of 83% O atoms and 17% F atoms. In addition, introducing F− ions into oxygen vacancies made BaY0.5Zr0.5O2.5F0.5 more stable and decreased the lattice content. This study provides new insights into the modification method of perovskite.