The effect of misfit strain on the phase diagram and pyroelectric effect in (110) oriented Pb(Zr1−xTix)O3 thin films

Abstract

Abstract The phase diagram and pyroelectric effect of (110) oriented Pb ( Zr 1 − x Ti x ) O 3 thin films with different Ti composition are investigated by a phenomenological Landau–Dovenshire theory. The tetragonal ( a 1 ) phase, the orthorhombic ( a 2 c ) phase, and the triclinic (γ) phase are stable. The compressive misfit strain favors the orthorhombic ( a 2 c ) phase, whereas the tensile misfit strain makes the triclinic (γ) phase and the tetragonal ( a 1 ) phase stable. At room temperature, the misfit strain induces the first order phase transition from the orthorhombic a 2 c phase to the triclinic γ phase in the Pb ( Zr 1 − x Ti x ) O 3 (x=0.4, 0.5, 0.6) thin films. Moreover, even in the γ phase of Pb ( Zr 1 − x Ti x ) O 3 (x=0.4, 0.5) thin films, the first order γ1–γ2 phase transition may happen with increasing the tensile misfit strain. The Pb ( Zr 0.5 Ti 0.5 ) O 3 thin film with the Ti composition around the morphotropic phase boundary has the largest dielectric and pyroelectric properties, which is in agreement with the experimental result. A critical electric field exists and results in the non-monotonic variation of dielectric and pyroelectric properties with the misfit strain in Pb ( Zr 0.5 Ti 0.5 ) O 3 thin film. The positive pyroelectric coefficient is obtained in the γ2 phase of Pb ( Zr 1 − x Ti x ) O 3 (x=0.4, 0.5, 0.6) thin films.