Film thickness dependence of electro-optic effects in epitaxial Ba0.7Sr0.3TiO3 thin films

Based on the phenomenological Landau-Devonshire thermodynamic theory, the film thickness dependence of ferroelectric and electro-optic properties of epitaxial Ba0.7Sr0.3TiO3 thin films is investigated. Theoretical analysis shows that the films of 600 nm thick grown on (001) LaAlO3 and (001) (LaAlO3)(0.3)(Sr2AlTaO6)(0.35) substrates have the large linear electro-optic effects, which are in good quantitative agreement with the experimental ones reported for the Ba0.7Sr0.3TiO3 thin films. Moreover, the obvious quadratic electro-optic effect is theoretically predicted for the film of 600 nm thick on (001) MgO substrate. (C) 2007 American Institute of Physics.