Challenges and opportunities of Coherent X-Ray Diffraction for 3D nanoscale imaging of domain in ferroelectric thin film during in-situ biasing

Overview & Synopsis

Understanding ferroelectric and ferroelastic domain behaviors at the local scale is essential to address structure/properties relationship in ferroelectric thin film. However, the case of polycrystalline thin films is particularly complex to model. Several effects (i.e. stress, substrate clamping, interface, grain boundary) affect the behavior of the domains in 3D. While 2D structures of domain are well documented thanks to piezo force microscopy or in-situ transmission electron microscopy, their 3D dynamic structures remain hardly measurable due to the lack of an adequate in-situ characterization technique. On the other hand, coherent X-ray diffraction imaging technique has been intensively developed during the last two decades in modern synchrotron light sources and can now offer 3D imaging with spatial resolution up to 10nm, hence compatible with ferroelastic domain size. More recently, this technique has also been extended to in-situ strain monitoring in polycrystalline thin films used for coatings . In this work, we proposed to implement this approach to polycrystalline ferroelectric thin films. Firstly, it will been shown how we succeed in collecting the diffraction signal from a single grain within a prototypal lead zirconate titanate (PZT) film during the application of an electrical cycle. Then phase retrieval strategy and its accuracy will be discussed through a numerical example [Fig]. This research contributes to a better understanding of the local behaviors in ferroelectric polycrystalline films and in the improvement of their performance for different applications.