Dielectric, Ferroelectric, and Piezoelectric Properties of Bi(Ni1/2Ti1/2)O3-Modified BiFeO3BaTiO3 Ceramics with High Curie Temperature


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New piezoelectric ceramics, 0.71BiFe1−x(Ni1/2Ti1/2)x O3−0.29BaTiO3+0.6 wt% MnO2 [BFNTx–BT] (= 0–0.09), were fabricated using conventional mixed-oxide method. It was found that the introduction of BNT into BF-BT system caused insignificant change in crystal structure, which is a single-phase perovskite structure. However, an obvious variation in microstructure took place. The ceramics with composition of = 0.03 showed enhanced piezoelectric, electromechanical, and ferroelectric properties with piezoelectric constant d33 = 156 pC/N, planar electromechanical coupling factors kp = 0.308, remnant polarization Pr = 22.5 μC/cm2, and coercive field Ec = 28.2 kV/cm, with a high Curie temperature Tc = 431°C, respectively. The combination of good piezoelectric properties and high Tc makes these ceramics suitable for elevated temperature piezoelectric devices.