Construction of 3D-Ferroelectric Polarization Microstructure and Detection of Polarization Invariants under Induced Flexoelectric Strains

Abstract

Ferroelectric thin films that are heterophased and polycrystalline possess strain sensitive piezoelectric behavior. However, a direct insight into polarization orientations within a given grain and how mechanical stresses reconfigures the ferro elastically coupled polarization orientations remains ambiguous. A polarization component resolved imaging in a Piezoresponse Force Microscope (PFM) was developed in combination with correlative structure and phonon studies that provide insights into grain orientation, domains and bending stress driven phase transitions. The method correlates the polarization invariant and the respective grain orientations present underneath. The technique facilitates an experimental inverse model approach to determine crystallographic grain orientation from the ferroelectric domain. A three point bending stage introduces a flexoelectric strain in Ba0.85,Ca0.15Zr0.1Ti0.9O3_BCZT thin films and simultaneous polarization imaging. This novel technique potentially captures the formation of new polarization invariant of a monoclinic phase that appears under high pressures. The experimental findings pave way for development of inverse modelling of heterophased and polycrystalline systems.