Strain effects and thickness dependence of ferroelectric properties in epitaxial BiFeO3 thin films

A “misfit strain-temperature” phase diagram for BiFeO3 thin film was constructed based on the Landau–Devonshire theory with the mechanical substrate effect. It is found that the polarization instabilities result in the formation of the monoclinic phases in BiFeO3 thin films. The effective substrate lattice parameter has been introduced to calculate the film thickness dependence of the polarization and the dielectric constants. The theoretical results are in agreement with the experimental data for the thickness dependence of ferroelectric properties of the BiFeO3 epitaxial thin films on SrTiO3 and Si substrates.Published versio