Stress modulation and ferroelectric properties of nanograined PbTiO ₃ thick films on the different substrates fabricated by aerosol deposition

Nanograined PbTiO₃ (PT) thick films were deposited on Si, yttria-stabilized zirconia (YSZ), and Ni substrates using an aerosol deposition (AD) method at room temperature. The AD PT thick films on each different substrate were annealed at 500°C and 700°C for 1 h to increase the crystallinity. The stresses in the PT film were modulated by controlling the difference in the coefficient of thermal expansion (CTE) between the films and substrates during the thermal annealing process. The morphology of the AD PT films was examined from the polycrystalline dense structure (thickness ~8 μm), and the changes in the crystallographic phase, in-plane stresses, and ferroelectric properties in annealed films were investigated. In-plane stress analysis showed that the PT films annealed at 500°C and 700°C on each substrate exhibited compressive stress. Owing to the effects of compressive stress in the PT film, the film showed less tetragonality (c/a ratio) and enhanced ferroelectric behaviors. The change in the polarization-electric field (P-E) hysteresis loop of the PT films was explained by the stress induced from CTE mismatch between the films and substrates.