Composition and phase structure in laser deposited and post-annealed Pb 1−3 y/2 Nd y(Zr xTi 1− x)O 3 thin films

Abstract

Pulsed XeCl excimer laser with a wavelength of 308 nm was used to ablate a Nd-modified lead–zirconate–titanate (PNZT), Pb 1−3 y/2 Nd y (Zr x Ti 1− x )O 3, ceramic target with y=0.02 and x=0.55 (Pb 0.97Nd 0.02(Zr 0.55Ti 0.45)O 3) with various laser-beam fluences between 0.2 and 3.0 J/cm 2. The target composition was near the morphotropic phase boundary (MPB) with a relative atomic Zr-content of B-site cations (Zr/(Zr+Ti)) x≈0.53 between the ferroelectric tetragonal and high-temperature rhombohedral phases of PZTs at room temperature. The films were deposited on single-crystal sapphire (Al 2O 3(11̄02)) and MgO(100) substrates without substrate heating. The phase structure and composition of both as-grown and post-annealed films were studied with X-ray diffraction measurements together with scanning electron microscopy (SEM) and energy dispersive spectroscopy of X-rays (EDS). The as-grown PNZT thin films after deposition were amorphous and crystallized during post-annealing in different phase structures depending on the ablation process conditions. The relative atomic zirconium content, Zr/(Zr+Ti), of the films depends on the laser-beam fluence used in the ablation, but is insensitive to post-annealing conditions.