Nanoindentation initiated dislocations in barium titanate (BaTiO3)

Plastic behavior during loading of ferroelectric bulk materials is commonly explained by domain switching processes. In this study the authors show that dislocation induced deformation also occurs during nanoindentation of BaTiO3. Studies were conducted using a spheroconical shaped indenter together with observations using atomic force microscopy (AFM) and focussed ion beam cross sections for transmission electron microscopy (TEM) of the contact areas. Force/displacement measurements showed the sudden appearance of “pop-in” events, which AFM/TEM observations revealed were associated with plastic deformation and dislocation arrays at the surface. TEM cross sections of the indents showed paired parallel slip lines with 45° to the original surface.