Abstract
The evolution of tetragonality with thickness has been probed in epitaxial -axis oriented films with thicknesses ranging from 500 down to . High resolution x ray pointed out a systematic decrease of the -axis lattice parameter with decreasing film thickness below . Using a first-principles model Hamiltonian approach, the decrease in tetragonality is related to a reduction of the polarization attributed to the presence of a residual unscreened depolarizing field. It is shown that films below display a significantly reduced polarization but still remain ferroelectric.
- Received 17 December 2003
DOI:https://doi.org/10.1103/PhysRevLett.94.047603
©2005 American Physical Society