The plastic behavior of (001) and (110) single crystals was studied by using atomic force microscopy and piezo-response force microscopy, following nano-indentation damage. The plastic deformation mechanisms of ferroelectric single crystals was considered with particular regard to the interaction between the piezo-response force and dislocation activity. Nano-indentation tests indicated that the theoretical strength was approached prior to the first pop-in event. This was consistent with the creation of dislocation nucleation sites required for the onset of plasticity. Surface topographic and piezoelectric analyses indicated that pile-ups around indents resulted from dislocation activity on the primary slip system, {110}p<1¯10>p. More complex indentation-induced domain patterns, observed on (110) samples, were also considered.

Indentation Plasticity of Barium Titanate Single Crystals - Dislocation Influence on Ferroelectric Domain Walls. D.Liu, M.Chelf, K.W.White: Acta Materialia, 2006, 54[17], 4525-31