In situ observation of ferroelastic domain evolution in a near-morphotropic Pb(Zr,Ti)O₃ ceramic by piezoresponse force microscopy

Ferroelastic domain evolution under compressive loading was observed in a near-morphotropic polycrystalline lead zirconate titanate ceramic using piezoresponse force microscopy (PFM). The PFM images show several evolution processes including overwriting of one lamellation by a differently oriented lamellation. Using electron backscatter diffraction and PFM data, we confirm that switching processes generally follow a primary principle: that positive work is done by external loads. However, this can occur by a combination of energetically favourable and unfavourable processes happening concurrently. The evidence suggests that switching processes are significantly constrained by pre-existing domain structures, such that the process is mainly one of pattern evolution. Since tetragonal and rhombohedral phases can coexist in the material, the analysis was carried out for both phases; the results enable the phase to be identified in some cases, provided that switching follows a positive work principle. The observations are discussed in the context of models of ferroelectric/ferroelastic switching.