Engineering polarization rotation in ferroelectric bismuth titanate

We report a combined experimental-theoretical study showing that collective application of rare earth doping on Bi-site of ferroelectric bismuth titanate (Bi4Ti3O12) and epitaxial strain leads to only a small increase in c-axis polarization, resolving conflicts of previous experimental data on c-axis oriented thin films. However, as shown by our first principles calculations, a modest c-axis polarization can be induced by simultaneous Bi(A) and Ti(B) site doping in bismuth titanate. This approach, correlating doping, epitaxial strain, and polarization in ferroic oxides, could be useful to tailor oxide compositions, assisting in the growth of epitaxial films along easy growth directions yielding reasonable polarization. (C) 2013 AIP Publishing LLC.