Domain structure of epitaxial PbTiO3 films grown on vicinal (001) SrTiO3

Abstract
Epitaxial PbTiO3 films have been grown on vicinal (001) SrTiO3 substrates by pulsed laser deposition. Vicinal SrTiO3 substrates with misorientations up to 9° from (001) were used, and the influence of the direction of misorientation on the resulting domain structure was studied. 4-circle x-ray diffraction analysis indicates that thin (40 nm) PbTiO3 films are completely c-axis oriented [rocking curve full-width-at-half-maximum (FWHM) of 0.25° for the 002 reflection] and that thicker films (∼ 200 nm) contain mixed a-axis and c-axis PbTiO3 domains due to twinning along {011} planes. The [100] axis of the a-axis domains is misoriented by 2.1° to 3.3° toward 〈100〉 substrate directions with respect to the substrate normal. In contrast to growth on well-oriented (001) SrTiO3 surfaces where the four equivalent tilts of the [100] axis of the a-axis domains are equally likely, on vicinal SrTiO3 the a-axis domains are preferentially oriented in an uphill direction with respect to the crystallographic miscut.