Studying the effects of Zr-doping in (Bi0.5Na0.5)TiO3via diffraction and spectroscopy

Abstract

The structural properties of (Bi_0.5Na_0.5)Ti_1−xZr_xO₃ (where 0 ≤ x ≤ 0.7) have been investigated using powder diffraction and X-ray absorption spectroscopy. Diffraction measurements on (Bi_0.5Na_0.5)TiO₃ confirm that both monoclinic Cc and rhombohedral R3c phases are present at room temperature. Doping small amounts of Zr into the B site of (Bi_0.5Na_0.5)TiO₃ initially stabilizes the rhombohedral phase before the orthorhombic Pnma phase begins to form at x = 0.5. Analysis of the Ti K-edge and Zr L₃-edge XANES spectra show that the crystallographic phase change has very little effect on the local structure of Ti⁴⁺/Zr⁴⁺ cations, suggesting that there is little change in the cation off-center displacement within the BO₆ octahedra with each successive phase change.