Ferroelectric property of a hydrothermally-grown PbTiO3 film with an aerosol-deposited seed layer

The hydrothermal method is a unique method for the growth of ferroelectric materials because their materials can be grown at a relatively low reaction temperature below 250 °C. To grow a PbTiO3 (PT) film on a metal Ni substrate, we first deposited a PT seed layer on the Ni substrate by using the aerosol deposition (AD) method; then we grew PT film on top of the PT seed layer by using the hydrothermal process. X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that the AD PT film acted well as a seed layer and that a highly-dense PT film had been successfully grown following the crystal structure of the seed layer. Both the PT seed layer and the hydrothermally-grown PT film had distorted crystal structures with decreased tetragonality. The output voltage due to impact on the film confirmed that the hydrothermally-grown PT film had a spontaneous polarization along the ‘c’ axis. The hydrothermally-grown PT film exhibited ferroelectric hysteresis loops without mechanical breakage during several cyclic measurements.