Size dependence of initial polarization direction in nanosized epitaxial PbTiO3 islands fabricated by hydrothermal epitaxy below Curie temperature

Abstract

Nanosized epitaxial PbTiO3 (PTO) islands with a mono c domain were fabricated via self-assembly on a Nb-SrTiO3 (NSTO) substrate at 160 °C by hydrothermal epitaxy without undergoing the paraelectric to ferroelectric phase transition. The direction of the polarization at the as-fabricated state was observed with an island size up to a lateral area of 104nm2 and thickness of 12 nm (determined by atomic force microscope) using a piezoresponse force microscope. We found a critical size below which the negative polarization is stable at the as-fabricated state and above which the positive polarization is stable. This phenomenon was discussed under two assumptions: that the PTO islands are grown initially with positive polarization during fabrication, and the energy barrier for the transition from the positive polarization state to the negative polarization state is dependent on the ferroelectric island size.

Retention loss behaviors in heteroepitaxial ferroelectric film with a +c monodomain fabricated by hydrothermal epitaxy below Tc

“…Details of the fabrication processes of the PTO islands are provided in the relevant literature. 19 To confirm the proposed model for the observed retention loss in the previous study, further retention loss experiments were carried out. To apply a homogeneous electric field, a heteroepitaxial PTO film capacitor with a Ni top electrode size of 50 m 2 was fabricated on continuous film.…”

Hydrothermal deposition of heteroepitaxial lead zirconate titanate nanostructures and thin films

“…Ahn et al showed, in 2005, that it was possible to produce epitaxial nanoislands of PZT on Nb-SrTiO 3 . 19 The growth of nanoislands on the substrate was also observed for PbTiO 3 by Szafraniak and Alexe, 20 and so this process of the nucleation of discrete nanoislands followed by coalescence to form a complete surface layer appears to be a common one.…”

Ferroelectric properties and fatigue behavior of heteroepitaxial PbZr1−xTixO3 thin film fabricated by hydrothermal epitaxy below Curie temperature

“…It was demonstrated that, with a theoretical approach, 22-24 the Pb-based perovskite ferroelectric thin films ͑PbTiO 3 and PZT͒ could be fabricated by hydrothermal epitaxy at temperatures below T C while avoiding phase transition. [17][18][19][20] As shown in Fig. 3͑a͒, the PZT thin film has a surface morphology of curved steps and terraces; the atomic force microscopy ͑AFM͒ observation shows that the step height was about 20 nm.…”

“…Ahn et al also used hydrothermal epitaxy to fabricate a nanosized epitaxial ͑001͒ PbTiO 3 island at 160°C below T c . 19 After finding a critical size, they deduced that below this critical size, the negative polarization was stable in the as-fabricated state, and above it, the positive polarization was stable. Recently, authors have fabricated a heteroepitaxial PbZr 1−x Ti x O 3 thin film on a cubic NSTO at 210°C, by hydrothermal epitaxy, without the PE to FE phase transition.…”