Indentation plasticity of barium titanate single crystals: Dislocation influence on ferroelectric domain walls

The plastic behaviors of barium titanate (0 0 1) and (1 1 0) single crystals are studied with atomic force microscopy and piezoresponse force microscopy (PFM) following nanoindendation damage. Plastic deformation mechanisms of ferroelectric barium titanate single crystals are discussed with a focus on the interaction between PFM response and dislocation activities. Nanoindentation tests indicate that the theoretical strength is approached prior to the first pop-in event, consistent with the creation of dislocation nucleation sites required for the onset of plasticity. Surface topographic and piezoelectric analyses indicate that pile-ups around indents result from dislocation activities on the primary slip system, {110}pc〈11¯0〉pc. The more complex indentation-induced domain patterns observed on (1 1 0) barium titanate are also discussed.