Domain structure of epitaxial PbTiO3 thin films on LaAlO3(100) grown by metal organic chemical vapor deposition

Abstract

Lead titanate (PbTiO3) thin film has been deposited on lathanum aluminate LaAlO3(100) (using pseudocubic index) single crystalline substrate by metal organic chemical vapor deposition at 550–700 °C. Microstructure of the films has been studied by the four-circle x-ray diffraction and transmission electron microscopy methods. Due to the noncubic symmetry of the LaAlO3 substrate at room temperature, the grown films exhibited more complex domain structure than those grown on cubic MgO or SrTiO3 substrates. The x-ray pole figure of LaAlO3 pseudocubic (002) peak has revealed two separate peaks at room temperature, indicating the existence of the two types of domain in the substrate. Consequently, the epitaxially grown PbTiO3 films were found to exhibit two distinguishable c domains, and eight a-domain peaks, as demonstrated by the x-ray pole figures employing PT(002) and PT(200) Bragg peaks. The domain structure and the domain formation mechanism are discussed in this article.