Normal‐Relaxor‐Diffuse Ferroelectric Phase Transition and Electrical Properties of Bi ( Mg 1/2 Ti 1/2 ) 3 – PbZrO 3 – PbTiO 3 Solid Solution Ceramics Near the Morphotropic Phase Boundary

Perovskite‐type x Bi ( Mg 1/2 Ti 1/2 ) O 3 –(0.56 −  x ) PbZrO 3 –0.44 PbTiO 3 ( x BMT – PZ – PT ) ternary solid solution ceramics were synthesized via a conventional solid‐state reaction method. The phase transition behaviors, dielectric, ferroelectric, and piezoelectric properties were investigated as a function of the BMT content. The X‐ray diffraction analysis showed that the tetragonality of x BMT – PZ – PT was enhanced with increasing the BMT content, and a morphotropic phase boundary ( MPB ) between rhombohedral and tetragonal phases was identified approximately in the composition of x  = 0.08. In addition, the dielectric diffuseness and frequency dispersion behavior were induced with the addition of BMT and a normal‐relaxor‐diffuse ferroelectric transformation was observed from the PZ ‐rich side to the BMT ‐rich side. The electrical properties of x BMT – PZ – PT ceramics exhibit obviously compositional dependence. The x  = 0.08 composition not only possessed the optimum properties with ε T 33 / ε 0  = 1450, Q m  =  69, d 33  = 390 pC/N, k p  = 0.46, P r  = 30 μC/cm 2 , E c  = 1.4 kV/mm, T c  = 325°C, and a strain of 0.174% ( d 33 *   = 436 pm/V) under an electric field of 4 kV/mm as a result of the coexistence of two ferroelectric phases near the MPB , but also owned a good thermal‐depolarization behavior with a d 33 value of >315 pC/N up to 290°C and a frequency‐insensitive strain behavior.