On ferroelectric domain polarization switching mechanism subject to an external electric field by simulations with the phase-field method

The ferroelectric domain formation (FDF) and polarization switching (FDPS) subjected to an external electric field are simulated using the phase-field (PF) method, and the FDPS mechanism under different external electric fields is discussed. The results show that the FDF is a process of nucleation and growth in ferroelectric without applying any external stress. Four kinds of parallelogram shaped ferroelectric domains are formed at the steady state, in which the 180° anti-phase domains regularly align along the -45° direction and the 90° anti-phase domains regularly distribute like a stepladder. Steady electric fields can rotate domain polarization by 90° and 180°, and force the orientation-favorite domains and the average polarization to grow into larger ones. The greater the steady electric field, the larger the average polarization at the steady state. In ferroelectrics subject to an alternating electric field, domain polarization switches to cause a hysteresis loop and an associated butterfly loop with the alternating electric field. The coercive field and remnant field are enhanced with the increase of the electric field frequency or strength, or with the decrease of temperature.