Ferroelectric domains in epitaxial PbTiO3 films on LaAlO3 substrate investigated by piezoresponse force microscopy and far-infrared reflectance

Abstract

Domain structures of 100–300 nm thin epitaxial films of ferroelectric PbTiO3 grown by metalorganic chemical vapor deposition technique on LaAlO3 perovskite substrate have been investigated by piezoresponse force microscopy and infrared reflectance spectroscopy techniques. Normal-incidence reflectance spectra reveal both E- and A1-symmetry modes of PbTiO3. The latter ones demonstrate the presence of a minor fraction of a-domains (with in-plane orientation of the spontaneous polarization) in the film. The piezoresponse force microscopy images allow to get local insight in the complex nanodomain architecture composed by few hundred nm large areas of primarily c/a/c/a but also a1/a2/a1/a2 domain pattern types, with participation of all six tetragonal ferroelectric domain states and both 180 ° and 90 ° ferroelectric walls.