Understanding the effect of porosity on the polarisation-field response of ferroelectric materials

Abstract

This paper combines experimental and modelling studies to provide a detailed examination of the influence of porosity volume fraction and morphology on the polarisation-electric field response of ferroelectric materials.The broadening of the electric field distribution and a decrease in the electric field experienced by the ferroelectric ceramic medium due to the presence of low-permittivity pores is examined and its implications on the shape of the hysteresis loop, remnant polarisation and coercive field is discussed. The variation of coercive field with porosity level is seen to be complex and is attributed to two competing mechanisms where at high porosity levels the influence of the broadening of the electric field distribution dominates, while at low porosity levels an increase in the compliance of the matrix is more important. This new approach to understanding these materials enables the seemingly conflicting observations in the existing literature to be clarified and provides an effective approach to interpret the influence of pore fraction and morphology on the polarisation behaviour of ferroelectrics. A new general rule to describe the relationship between the polarisation and porosity is also proposed. Such information provides new insights in the interpretation of the physical properties of porous ferroelectric materials to inform future effort in the design of ferroelectric materials for piezoelectric sensor, actuator, energy harvesting, and transducer applications.

Electromechanical Properties of Robocasted Barium Titanate Ceramics

“…Furthermore, pores could orient in a similar fashion as particles, thus changing the anisotropy of the properties. Zhang et al showed that the reduction of the remanent polarization with increasing porosity is lower in case of pores aligned to the applied electric field, [ 56 ] indicating that the effect on the piezoelectric charge coefficient is lower for aligned pores. Thus, pores seem to be the major contributor of the BT50 samples, which is even more apparent when compared with the BT52 samples.…”

Multifunctional nanopatterned porous bismuth ferrite thin films

“…The obtained (d 33 ) eff value for dense thin films is comparable to the values previously reported for dense BiFeO 3 thin films prepared by soft chemical deposition. 26,33 Recently, Zhang et al 34 reported experimental and modelling studies on the effect of the macro porosity volume fraction and morphology on the polarisation-electric field response of ferroelectric bulk materials. The results of the authors corroborate the results described here as they observed that porosity up to 25% volume leads to a decrease in coercive field with increasing porosity, and this was justified by the increase of compliance of the ceramic matrix which facilitates non-1801 domain switching.…”

On the importance of pyrolysis for inkjet-printed oxide piezoelectric thin films

“…However, the relationship between coercive field and porosity is not trivial and often nonlinear, as it can be influenced by the level of porosity and its distribution in the film. 31,32 PZT films pyrolyzed at the highest temperature (475 1C) display a remanent polarization of 23.7 mC cm À2 . Fig.…”