Ferroelectric BiFeO3-PbTiO3 thin films on Pt/Si substrates

In this work we report on the preparation and properties of bismuth ferrite lead titanate films [(1-x)BiFeO_3-xPbTiO₃] with tetragonal compositions (x = 0.8 and 0.7) and compare them with compositions close to the morphotropic phase boundary (MPB; x = 0.4 and 0.3). The films were prepared by pulsed laser deposition on Pt/Si substrates, and exhibited a dense columnar grain growth. X-ray diffraction analysis revealed that the films have a perovskite structure with a preferred (111) texture. The dielectric properties, polarization-field hysteresis, and leakage current behavior of the films is also reported. For MPB compositions, the films exhibited remanent polarizations with 2P_r up to 100 muC cm^-2 and E_c ~ 185 kV cm^-1 under a maximum applied field of 500 kV cm^-1, while the tetragonal compositions exhibited 2P_r values in the range of 45-52 muC cm^-2 with a coercive field E_c ~ 118 kV cm^-1.