Large spontaneous polarization in polar perovskites of PbTiO3–Bi(Zn1/2Ti1/2)O3

Abstract

PbTiO₃–Bi(Zn_1/2Ti_1/2)O₃ is considered to be a promising high-ferroelectric performance material in the Pb/Bi-based perovskite family. In the present study, a whole set of (1 − x)PbTiO₃–xBi(Zn_1/2Ti_1/2)O₃ (0 ≤ x ≤ 1) solid solutions have been prepared by the conventional solid-state and high-pressure vs. high-temperature methods. The effect of Bi(Zn_1/2Ti_1/2)O₃ on the crystal structure has been investigated by synchrotron X-ray powder diffraction. Unlike most PbTiO₃-based perovskites, the present system exhibits a continuously enhanced tetragonality (c/a) and large spontaneous polarization (P_S) properties. The enhanced c/a is ascribed to the large spontaneous polarization displacements induced by the strong Pb/Bi–O hybridization and coupling interactions between Ti/Zn and Pb/Bi cations, which can be evidenced from the lattice dynamics study and first-principles calculations. Accordingly, the T_C (i.e., x = 0.5) is expected to be approximately 1000 °C if its perovskite structure can be stabilized. The present study provides a route to obtain large-P_S in PbTiO₃-based ferroelectric materials by introducing isostructural perovskites with strong polarity.