A study was made of the strain field around the 90° domains and misfit dislocations in PbTiO3/SrTiO3 (001) epitaxial thin films, at the nanoscale, using the geometric phase analysis combined with high-resolution transmission electron microscopy and high-angle annular dark field scanning transmission electron microscopy. The films typically contain a combination of a/c-mixed domains and misfit dislocations. The PbTiO3 layer was composed from the two types of the a-domain (90° domain): a typical a/c-mixed domain configuration where a-domains were 20 to 30nm wide and nano sized domains with a width of about 3nm. In the latter case, the nano sized a-domain does not contact the film/substrate interface; it remains far from the interface and stems from the misfit dislocation. Strain maps obtained from the geometric phase analysis of high-resolution transmission electron microscopy images show the elastic interaction between the a-domain and the dislocations. The normal strain field and lattice rotation match each other between them. Strain maps reveal that the a-domain nucleation takes place at the misfit dislocation. The lattice rotation around the misfit dislocation triggers the nucleation of the a-domain; the normal strains around the misfit dislocation relax the residual strain in a-domain; then, the a-domain growth takes place, accompanying the introduction of the additional dislocation perpendicular to the misfit dislocation and the dissociation of the dislocations into two pairs of partial dislocations with an APB, which was the bottom boundary of the a-domain. The novel mechanism of the nucleation and growth of 90° domain in PbTiO3/SrTiO3 epitaxial system was proposed based on above the results.Configuration and Local Elastic Interaction of Ferroelectric Domains and Misfit Dislocation in PbTiO3/SrTiO3 Epitaxial Thin Films. T.Kiguchi, K.Aoyagi, Y.Ehara, H.Funakubo, T.Yamada, N.Usami, T.J.Konno: Science and Technology of Advanced Materials, 2011, 12[3], 034413