Coupling electro-mechanical behaviors in the interdigital electrode device of ferroelectrics

Abstract

The electro-mechanical coupling behaviors of ferroelectric devices with interdigital electrodes may become complicated due to the material inhomogeneity and local field concentration under the complex working conditions. In this paper, a ferroelectric model, drawn from the typical interdigital electrode structure of a ferroelectric sensor, is established based on phase field theory, to study the polarization evolution and explore the evolution laws in ferroelectrics. Numerical results show that there appears ferroelectric creep even under an applied electric field below the coercive field value. Also, the configurational force theory is introduced to investigate the mechanical behaviors related to polarization switching in the ferroelectric samples with interdigital electrodes. It is found that configurational force and polarization have similar evolution laws in both time evolving and space distribution. And considering the configurational force as the driving force, it is possible to predict the potential direction of polarization evolution and explore its evolution mechanism in ferroelectrics, demonstrating the configurational force as a useful parameter for describing mechanical behavior during the polarization evolution and a powerful tool for investigating the evolution mechanism of microstructure with coupling effects in ferroelectric materials. Graphic abstract