Dependence of lattice distortion of monoclinic phase on film thickness in Pb(Zr0.58Ti0.42)O3 thin films

In this paper, the chosen composition of PZT film falls in rhombohedral phase region and the dependence of lattice distortion on film thickness in sol-gel derived Pb(Zr_0.58Ti_0.42)O₃ thin films was systematically investigated. The results confirm that the Pb(Zr_0.58Ti_0.42)O₃ films have monoclinic phase even though the composition falls in the rhombohedral phase region. The mixed textures of (1 0 0) and (1 1 1) occur in the PZT films. In the case of mixed textures, a method using ψ-scan XRD to characterize the phase type of Pb(Zr_0.58Ti_0.42)O₃ film is presented. It is found that the phase type of (1 0 0)-oriented grains is M_A phase, and that of (1 1 1)-oriented grains is M_B phase. Moreover, the lattice constants of both M_A and M_B phases are sensitive to the film thickness. The lattice distortion of monoclinic phase becomes smaller as film thickness increases.