Structural evidence for the nonmonotonic trend of TC in tetragonal PbTiO3BiScO3 solid solutions

Abstract

High-TC piezoelectric (1−x)PbTiO3xBiScO3 shows a nonmonotonic trend of TC in the tetragonal phase with respect to content of BiScO3. To understand this behavior, the structure of (1−x)PbTiO3xBiScO3 solid solutions is studied by means of neutron powder diffraction. The cation displacements of Pb/Bi and Ti/Sc exhibit a coupling property and a different impact by the substitution content of BiScO3. Its nonmonotonic trend of TC is quantitatively related to the calculated spontaneous polarization in the whole tetragonal range. The unique role of Bi-substitution not only contributes to enhance the component of polarization of Pb/Bi but also to increase the TC.