Dislocations and a domains coupling in PbTiO3 thin films

The interaction of domain structure and defects in ferroelectric thin films has been studied for decades. However, the role of dislocations and thermal stability of microstructures is still poorly studied. By combining transmission electron microscopy, x-ray diffraction experiments, and phase-field simulations, we show that dislocation pairs induced by post-annealing above 550 degrees C provide a stress field stabilizing a domains in 30 nm thick tetragonal PbTiO3 films on SrTiO3 substrate, initially exhibiting pure c domains. Based on phase-field simulations, we further discuss the effects of single dislocations and dislocation pairs on the nucleation of a-domains and the occurrence of non-ferroelastic 180 degrees domains. Dislocations, and the possibility to tune them using an appropriate thermal annealing process, offer a path for modulating the domains and domain wall states and, thus, the physical properties of ferroelectric films.

Automated summary

The interaction between domain structure and defects in ferroelectric thin films has been a focus of research. This study demonstrates the role of dislocations in stabilizing the domains of PbTiO3 films on a SrTiO3 substrate during post-annealing above 550 degrees C. The effects of single dislocations and dislocation pairs on domain formation were also explored.