Micro-/macro-responses of a ferroelectric single crystal with domain pinning and depinning by dislocations

Phase field simulations are conducted to investigate the micro-structural signature and the macro-response of a ferroelectric single crystal with domain pinning and depinning phenomena bydislocation arrays. It is shown that due to the presence of the dislocation arrays, a domain withpolarizations antiparallel to an applied field can survive under the small amplitude of applied field. The residual domain serves as a pre-existing nucleus during the following macroscopic switching via only domain wall motion. The pinned domain will be depinned when the external electric fieldamplitude exceeds a critical value, which highly depends on the dislocation spacing in the dislocationarray. Due to the pinning and depinning effect, an asymmetric hysteresis loop of polarization versuselectric field might appear when a bias field is applied.