Mixture domain states in PbTiO3 film with potentials for functional application

We investigated the microstructure of PbTiO3 films epitaxially grown on DyScO3 (110) substrates using synchrotron-based 3D reciprocal space mapping and X-ray reflection interface microscopy. The results show that an in-plane anisotropic mixture domain state (a* + a/c) exists in the PbTiO3 films, where a* domains reside between a/c twin stripe domains. Furthermore, when compared with traditional a domains in a/c twins, the a* domain is found to possess a similar in-plane lattice parameter but a much smaller out-of-plane lattice (∼0.5%). We also discovered a temperature-driven transition between a* and a/c pointing to potential applications in functional devices due to the huge mechanical response (4.85%) and polarization rotation between the a* and c domains.