MPB phase diagram and ferroelectric properties in the PbTiO3-BiScO3 system

Perovskite solid solutions (1 - x)PbTiO3(PT)-xBiScO(3)(BS) were prepared under ordinary pressure. Single phase tetragonal perovskite was obtained up to the composition x = 0.375, and morphotropic phase boundary (MPB) from tetragonal to rhombohedral phase was also situated on this composition. The dielectric measurements suggested existence of critical compositions around both x = 0.15 and x = 0.3. The Curie temperature (T-C) was higher than that of PT at x = 0.1-0.2. Below and above x = 0.3, the dielectric constant at T-c increased and decreased with increasing BS content, respectively. These dielectric behaviors seemed to be associated with the connectivity of TiO6 octahedron and ScO6 octahedron in the perovskite structure.