Structure and Ferroelectric Properties of (Bi0.5Na0.5)0.9Ba0.07Sr0.03TiO3 Ceramics by Mn Doping

Abstract

The effect of a small amount of MnO₂ doping on the structure and ferroelectric properties of (Bi_0.5Na_0.5)_0.9Ba_0.07Sr_0.03TiO₃ (BNBST) ceramics prepared by the conventional mixed oxide method was systematically investigated. X-Ray diffraction shows that all ceramics samples have a pure perovskite structure and a morphotropic phase boundary between tetragonal and rhombohedral phase locates in the range of 0.20 < x < 0.75. At x = 0.25, the MnO₂-modified BNBST ceramics exhibit excellent ferroelectric properties composed by a higher remanent polarization P_r (P_r = 25.9 μC/cm²) and lower coercive field E_C (E_C = 2.54 kV/mm) at room temperature. Moreover, the two characteristic dielectric peaks can be observed in this ceramics.