Can interface dislocations degrade ferroelectric properties?

The role of dislocations in ferroelectric materials was investigated by a thermodynamic analysis. A drastic variation in the polarization near the dislocation is observed due to the coupling of the stress field of the dislocation and polarization. These polarization gradients result in string depolarizing fields that suppress the polarization in a region that extends over several nanometers. The deterimental effect of such regions increases in ultrathin ferroelectric thin films and play a crucial extrinsic role in size effect studies of ferroelectrics.