Crystal structure and ferroelectric properties of Bi_0.5Na_0.5TiO₃-modified Bi_0.5+0.5xNa_0.5−0.5xTi_1−xMn_0.75xMo_0.25xO₃ solid solutions

Abstract

In this study, Bi_0.5+0.5xNa_0.5−0.5xTi_1−xMn_0.75xMo_0.25xO₃ (BNTMM) ceramics were synthesized and the influence on their crystal structure and ferroelectric properties of the Bi, Mn and Mo substitutions for Na and Ti was investigated. Based on variations in the lattice parameters, the solubility limit was determined to be x = 0.0075. From crystal structural refinement in the single phase region, it was found that the Bi, Mn and Mo substitutions for Na and Ti may exert an influence on the covalency of B–O (B = Ti, Mn, and Mo) and (Bi,Na)–O bonds, leading to a structural distortion of BO₆ octahedra and (Bi,Na)O₁₂ polyhedra, which may affect the remnant polarization (P_r). The highest P_r value of 40.3 µC/cm² was obtained for x = 0.0075 and the corresponding coercive field E_c was 70.3 kV/cm.