Strain-driven domain structure control and ferroelectric properties of BaTiO3 thin films

We have studied the domain structure formation in annealed BaTiO 3 films grown on SrTiO 3 . We show that it is possible to utilize the 2.28% lattice mismatch strain at the SrTiO 3 /BaTiO 3 interface to obtain uniaxially c -axis-oriented BaTiO 3 films with a thickness of up to about 200 nm. This thickness is much larger than the typical critical thickness for BaTiO 3 films on SrTiO 3 and such films therefore can potentially be useful for optical waveguide applications. We also looked at the polarization properties of the uniaxial BaTiO 3 films. Our measurements and analysis indicate that the heavily distorted interface region, with a thickness of approximately 2 nm is non-ferroelectric.