Local Structure Analysis of Bi_0.5Na_0.5TiO₃, Bi_0.5Na_0.4Li_0.1TiO₃, and 0.95Bi_0.5Na_0.5TiO₃⋅0.05BaMn_1/3V_2/3O₃

Abstract

The potential lead-free piezoelectric bismuth sodium titanate, Bi0.5Na0.5TiO3 (BNT) solid solution, was investigated by means of an atomic pair-distribution function (PDF) method. BNT has been presumed thus far to exhibit the rhombohedral space group R3c at room temperature. The A site in BNT with an ABO3 perovskite structure was modified by Li and Ba atoms. Although average structures of the obtained Bi0.5Na0.4Li0.1TiO3 (BNLT) and 0.95Bi0.5Na0.5TiO3⋅0.05BaMn1/3V2/3O3 (0.95BNT⋅0.05BMV) solid solutions were similar to that of pure BNT, the local structures of these BNT-based compounds were slightly changed. In pure BNT, Bi atoms were shifted from the lattice point of the average structure. The bonds between Bi and O split in two PDF peaks owing to the off-center shift of Bi atoms. The modification of the A-site atoms in BNLT and 0.95BNT⋅0.05BMV to the BNT structure produces an apparent change in their local structures around Bi atoms.