Suppression of antiphase domain boundary formation in Ba 0.5Sr 0.5TiO 3 films grown on vicinal MgO substrates

The epitaxial growth of Ba 0.5Sr 0.5TiO 3 (BST) thin films on MgO vicinal substrates by pulsed-laser deposition and molecular-beam epitaxy was described. The [001] oriented MgO substrates with 2° and 5° miscut toward [010] were considered. It was shown that the nucleation of antiphase domain boundaries in the direction parallel to the step edges was greatly reduced in BST films grown on the vicinal substrates compared to the films grown on flat substrates. It was observed that the reduction in antiphase domain boundaries gives rise to a higher dielectric constant when the electrodes were parallel to the direction of the steps, by about 280-460, than in the perpendicular direction.