Substrate influence on the shape of domains in epitaxial PbTiO3 thin films

Abstract

Epitaxial PbTiO 3 thin films were grown on SrTiO 3 ͑001͒ and DyScO 3 ͑110͒ substrates by pulsed laser deposition. We used high-resolution transmission electron microscopy to investigate the 90°d omain structure in the films. They were found to have a predominant fraction of c domains along with a certain minor volume fraction of a domains that is clearly higher in case of the DyScO 3 substrates. In PbTiO 3 on SrTiO 3 the a domains were found to have a wedge shape, whereas in PbTiO 3 on SrRuO 3 / DyScO 3 they have a nearly uniform width. The presence of steps in the domain walls has been observed in the films on both substrates, but the steps are clearly more dominant in the case of SrTiO 3 than of SrRuO 3 / DyScO 3 and are responsible for the observed wedge shape. The observed difference in the films induced by the two substrates is attributed to a higher stiffness of SrTiO 3 than of SrRuO 3 / DyScO 3 as we corroborated with nanoindentation experiments.

Strain on ferroelectric thin films

“…This was later confirmed by calculations [162]. In addition, the domains were observed to start from dislocations standing off the interface [71]. This shape minimizes the strain at the interface due to the clamping on the substrate and enables the misorientation to be compensated.…”

“…This shape minimizes the strain at the interface due to the clamping on the substrate and enables the misorientation to be compensated. This shape is however a function of the stiffness of the substrate, a higher stiffness leading to a higher interface strain and therefore minimizing the width of the a domain a the interface with substrate [71,162]. As a consequence, the a domain walls observed on the SrRuO 3 electrode deposited on DyScO 3 were parallel [71].…”

“…This shape is however a function of the stiffness of the substrate, a higher stiffness leading to a higher interface strain and therefore minimizing the width of the a domain a the interface with substrate [71,162]. As a consequence, the a domain walls observed on the SrRuO 3 electrode deposited on DyScO 3 were parallel [71]. It has to be noted that domains were intentionally generated in these PbTiO 3 films deposited on SrTiO 3 by modifying the deposition conditions.…”

“…1 implies to take a closer look at the situation near the interface with the surface. Instead of parallel domain walls, steps have been observed by transmission electron microscopy [71] in the domain wall profile leading to wedge-shaped a domains. This was later confirmed by calculations [162].…”

Reconstructions at complex oxide interfaces

“…[8,[28][29][30] However, surface treatments for perovskite-type scandates have hardly been addressed in literature. [31][32][33] Recently, Dirsyte et al showed that annealing of DyScO 3 at high temperatures in …”