Structural and electrical properties of Bi_0.5Na_0.5TiO₃ templates produced by topochemical microcrystal conversion method

Bi_0.5Na_0.5TiO₃ (BNT) templates with a single phase perovskite structure were produced from a plate-like precursor particles of bismuth-layer-structured ferroelectric Bi_4.5Na_0.5Ti₄O₁₅ (BNT4) through a topochemical microcrystal conversion process. First, the plate-like BNT4 precursor particles were prepared via molten salt synthesis. The layered structure BNT4 transformed into a single phase perovskite BNT templates after its topochemical reaction with the complementary Na₂CO₃ and TiO₂ reactants at 950°C for 4 h in a NaCl flux. The as synthesized BNT templates exhibited large grains (range from 10 to 15 μm), had plate-like morphology and exhibits a single-phase perovskite structure with a pseudo-cubic symmetry. Furthermore, the temperature dependences of dielectric constant and loss at different frequencies showed a relaxor behavior, and polarization versus electric field curves exhibited a typical ferroelectric response.