Dielectric and piezoelectric properties of (110) oriented Pb(Zr1−xTix)O3 thin films**Project supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions, China, the Research Fund of Jiangsu Province Cultivation Base for State Key Laboratory of Photovoltaic Science and Technology, China, Major Projects of Natural Science Research in Jiangsu Province, China (Grant No. 15KJA43002), and Qing Lan Project of Education

Abstract

A phenomenological Landau–Devonshire theory is developed to investigate the ferroelectric, dielectric, and piezoelectric properties of (110) oriented Pb(Zr1−xTix)O3 (x = 0.4, 0.5, 0.6, and 0.7) thin films. At room temperature, the tetragonal a1 phase, the orthorhombic a2c phase, the triclinic γ1 phase, and the triclinic γ2 phase are stable. The appearance of the negative polarization component P2 in the a2c phase and the γ1 phase is attributed to the nonlinear coupling terms in the thermodynamic potential. The γ phase of the Pb(Zr1−xTix)O3 thin films has better dielectric and piezoelectric properties than the a2c phase and the a1 phase. The largest dielectric and piezoelectric coefficients are obtained in the Pb(Zr0.5Ti0.5)O3 thin film. The piezoelectric coefficient of 110–150 pm/V is obtained in the (110) oriented Pb(Zr0.5Ti0.5)O3 thin film, and the Pb(Zr0.3Ti0.7)O3 thin film has the remnant polarization and relative dielectric constant of 50 μC/cm2 and 100, respectively, which are in agreement with the experimental measurements reported in the literature.