Retention loss phenomena in hydrothermally fabricated heteroepitaxial PbTiO ₃ films studied by scanning probe microscopy

We observed the retention loss phenomena of the nanodomains with an average diameter of 36 nm and that of the square domains with a size of 1 and 25 μ m2 that were reversed by an applying electric field at an atomic force microscopy conductive tip in a heteroepitaxial PbTi O3 thin film, which was fabricated via hydrothermal epitaxy below Curie temperature, TC. While the nanodomains did not undergo significant retention loss until 5.3× 106 s, the square domains revealed some retention loss for a fixed period after long latent periods. The observed phenomena were explained in terms of the instability of the curved cc domain wall and the compressive strain energy. Analyses showed that the nanodomains composed a cylinder extending to the bottom electrode; however, the square domains had a curved cc domain wall, including the compressive strain energy, and these factors caused the retention loss.