PHASE TRANSFORMATION CHARACTERISTICS OF BARIUM STRONTIUM TITANATE FILMS ON ANISOTROPIC SUBSTRATES WITH (001)//(001) EPITAXY

ABSTRACT

The role of anisotropic misfit strains on the spontaneous polarization of (100) oriented Ba_0.6Sr_0.4TiO₃ thin films on (100) orthorhombic substrates is theoretically analyzed. A modified thermodynamic model is utilized to evaluate the equilibrium polarization values as a function of the anisotropic misfit strains. Results show that ferroelectric phases that cannot be observed in single-crystal Ba_0.6Sr_0.4TiO₃ can be stabilized due to the reduction in the symmetry induced by the anisotropic strain state.

Keywords:

• Ferroelectric thin films
• anisotropy
• monoclinic phase
• thermodynamics

ACKNOWLEDGMENTS

The authors gratefully acknowledge support by the NSF under Grant No. DMR-0132918 and U.S. Army Research Office through Grant W911NF-05-1-0528.