Existence of Large Room Temperature Ferroelectricity in Chemical Solution Grown PbTiO3 Buffered (BiFeO3)1-x-(PbTiO3)x Films on Pt/Si Substrates

Here, we report the existence of large remnant polarization and dielectric constant in PbTiO3 buffered polycrystalline (BiFeO_3)_{1-x} (PbTiO_3)_x thin films of composition x = 0.25, 0.30 and 0.35 around the morphotropic phase boundary. The films were deposited by chemical solution deposition on platinized silicon substrates. Films reveal a perovskite structure with a tendency to retain rhombohedral structure even at higher PbTiO_3 content than that reported in bulk. We observe very large remnant polarization, ~75 microC/cm^2, and high dielectric constant, ~2400 at 1 kHz for x = 0.3, which lies in the MPB composition range. The unbuffered films show less than 1 microC/cm^2 for the same composition.