Effective Properties of 2D and 3D Porous Ferroelectric Composites
Please login to view abstract download link
The design of novel ferroelectric materials with tailored properties has become an area of growing interest over last decades, as they have been demonstrated to be suitable candidates for applications in microelectronic circuits and microwave devices. The functional performance of ferroelectric composites strongly depends on microstructural characteristics, the control of which enables tailoring of their effective properties. Here, we propose a simple yet effective numerical approach to characterize the effective electric properties and polarization hysteresis behaviour of 2D and 3D porous ferroelectric-dielectric composites. The approach integrates the phenomenological model proposed by Miller et al. for the description of the field-dependent polarization of pure ferroelectrics into a finite element method analysis that solves continuum electrostatics equations for local electric fields in the composites. We apply this approach to composite structures generated using the Metropolis Monte Carlo algorithm and composed of pores, in the form of either monodisperse circular disks or spheres with specified volume fractions and degree of impenetrability, randomly distributed in a continuous ferroelectric matrix. The calculated electric field-dependent effective polarization hysteresis loop and permittivity of such ferroelectric composites with different compositions reveal their strong dependence on the degree of disks impenetrability, volume fraction, and dimensionality. Furthermore, simulations unveil a critical influence of the structural parameters and percolation threshold on the coercive field, remnant polarization, and saturation polarization of the composites. This study adds an important dimension to our understanding of the role of connectedness, porosity, and disorder in determining the effective characteristics of ferroelectric composites.
