Abstract:
By employing a dipole defect model, two-dimensional phase field simulations of domain switching in the crack tip vicinity of a crack embedded in a relaxor ferroelectric single crystal subjected to mechanical loading were carried out. The interaction between the dipole defects and crack, and the influence of the dipole defect concentration density on the switching process has been investigated. Comparison of the results obtained from normal and relaxor ferroelectrics showed that for the latter the polarization switching in the vicinity of the crack tip was suppressed and the field distribution was not symmetric to the crack surface, which was different from those of the former. These were due to the interaction between the dipole defects and crack, and the inhomogeneous field induced by dipole defects. Moreover, the polarization switching rate and switching zone area decreased with the increase of dipole defect concentration density.