Enhanced piezoelectric and antiferroelectric properties of high-TC perovskite of Zr-substituted Bi(Mg1/2Ti1/2)O3-PbTiO3

Abstract

Bi(Mg1/2Ti1/2)O3-PbTiO3 is a promising high-TC piezoelectrics in the Bi-based perovskite family of BiMeO3-PbTiO3. In this study, zirconium is utilized to further improve the high temperature piezoelectric properties of Bi(Mg1/2Ti1/2)O3-PbTiO3. Substitution of Zr for Ti is observed to decrease the tetragonality (c/a) near the morphotropic phase boundary, while TC can be well maintained by the substitution of smaller and ferroelectrically active Ti by a larger and ferroelectrically weaker Zr cation. A softer coercive field and enhanced domain mobility is observed, ultimately leading to a strong ferroelectric activity. The piezoelectric property of Zr-substituted Bi(Mg1/2Ti1/2)O3-PbTiO3 is enhanced to 260 pC/N, when compared with Bi(Mg1/2Ti1/2)O3-PbTiO3 (225 pC/N). Good high temperature piezoelectric property was found in the tetragonal phase of Zr-substituted Bi(Mg1/2Ti1/2)O3-PbTiO3. Thermal depoling of aligned domains for this composition occurs at approximately 300 °C. Thus, Zr-substituted Bi(Mg1/2Ti1/2)O3-PbTiO3 could be used for high temperature actuator applications. Furthermore, an apparent ferroelectric-antiferroelectric phase transition was observed as a function of both the composition in the rhombohedral phase and the temperature. An antiferroelectric relaxor exists in the Zr-substituted Bi(Mg1/2Ti1/2)O3-PbTiO3.