We observed the retention loss of dot domains (36 nm diameter) and square domains with sizes of 1 and 25 mu m(2) that were reversed by applying an electric field at an atomic force microscopy (AFM) conductive tip on a heteroepitaxial PbTiO3 thin film with + polarization in the virgin state, which was fabricated via hydrothermal epitaxy below T-c. Through theoretical calculations, it was discussed that the retention loss phenomena of a domain reversed by using an AFM tip were derived from the summation of the depolarization field energy and the strain-polarization coupling energy. Since the retention loss of the reversed domain with a straight c/c domain wall by applying a homogeneous electric field did not occur, we suggest that a cylindrical domain, which has a nearly straight c/c domain wall that extends to the bottom electrode on the given thin film, would be free from the retention loss. (c) 2006 American Institute of Physics.