X-ray characterization of the domain structure of epitaxial lead titanate thin films on (001) strontium titanate

The coherency of the domain walls forming between the a and c domains in epitaxial lead titanate films forces a tilt in the a-domains with respect to the surface normal of the (001)SrTiO3 substrate. It is shown that the measurement of the relative volume fraction of the domains requires mapping of the x-ray diffraction intensity distribution in the reciprocal space. Maps for lead titanate films of different thickness show that a domains are essentially absent in films less than 50 nm thick and approach 25% volume fraction at a thickness of 350 nm. The tilt angle, which lies in the range 2.65±0.5°, remains unchanged with thickness.