The unusual temperature dependence of the switching behavior in a ferroelectric single crystal with dislocations

The unusual temperature-induced switching behavior in a ferroelectric single crystal with dislocation arrays is investigated by using phase field simulations. The results show that the influence of temperature on the hysteresis loop of a ferroelectric is dependent on the dislocation arrays. In the presence of dislocation arrays, the dependence of the coercive field on the temperature is different from that of a dislocation-free ferroelectric. The coercive field increases when the temperature increases from room temperature to a critical temperature, which is attributed to the pinning of domains by the dislocation arrays. Above the critical temperature, both the coercive field and the remnant polarization decrease with temperature. It is found that double hysteresis loops can be induced by dislocation arrays when the temperature is higher than the Curie temperature. This work exhibits the complex role of temperature and dislocations in the polarization switching of ferroelectric single crystal. (paper)