Structure‐property relationships in BiScO 3 –PbTiO 3 –PbMg 1/3 Nb 2/3 O 3 ceramics near the morphotropic phase boundary

The phase structure, dielectric, ferroelectric, and piezoelectric properties of (1−2 x )BiScO 3 – x PbTiO 3 – x PbM g 1/3 Nb 2/3 O 3 ceramics ( x = 0.30‐0.46) were studied. It was found that an increase in x leads to a structural phase transition between the rhombohedral and tetragonal phase via an intermediate monoclinic phase and to a crossover from the nonergodic relaxor state to the ferroelectric one. It was proposed that at x > 0.42 the phase transition changes from second to first order. The assumption about the existence of a tricritical point on the phase diagram at x ≈ 0.42 with the enhanced dielectric response has been made. The observed structure‐property relationships of the studied solid solutions are discussed. It is shown that the solid solutions with x = 0.42 are characterized by the high piezoelectric parameters ( d 33 = 509 pC /N, d 31 = −178 pC/N, d h = 153 pC/N), which makes possible their applications in sonar equipment.