Domain Structure and Enhanced Electrical Properties in Sodium Bismuth Titanate Ceramics Sintered from Crystals with Different Morphologies

Sodium bismuth titanate (Na_0.5Bi_0.5TiO₃, NBT) crystals with different morphology, wires, plates and cubes, were synthesized by hydrothermal method. The domain structure in as-synthesized poled NBT ceramics was observed. The results demonstrate that the domain width of the poled NBT ceramics sintered from wire crystals is slightly larger than that of the NBT ceramics sintered from cube crystals, while the NBT ceramics sintered from plate crystals possess the largest domain width. In particular, the poled NBT ceramics sintered from plate crystals exhibit the optimum piezoelectric coefficient and remnant polarization of 87 pC/N and 36.7 μC/cm², respectively, which are 55% and 37% higher than those of the NBT ceramics sintered from cube crystals. The expanded domain width and large grain size are responsible for the improvement of ferroelectric, piezoelectric, and dielectric properties in NBT ceramics.