Non-180 domain wall movement, which makes a large contribution to the piezoelectric response of ferroelectric bulk materials, were found to be much more difficult in epitaxial films, because of substrate clamping and inter-domain pinning. Through theoretical calculations and experimental studies we show that by choosing the film composition on the morphortropic phase boundary, it is possible to form a mobile , 2-domain architecture in an epitaxial PbZrxTi1-xO3 film with a (101) orientation. Transmission electron microscopy, X-ray diffraction analysis, and atomic force microscopy revealed that the (101) films feature a self-assembled polydomain structure, consisting of two domain sets of a tetragonal phase. Experiment results on the (101) films exhibits a reversible longitudinal strain as high as 0.35% under applied ac electric fields of ~30kV/cm, corresponding to an effective piezoelectric coefficient on the order of 1,000 pm/V. This result suggests an optimized design of ferroelectric thin film heterostructures for better electromechanical performance.
Citation: Advanced Functional Materials
Pub Type: Journals
domains, piezoelectric, self-assembled, thin films