Mapping nanoscale domain patterns in ferroelectric ceramics by atomic force acoustic microscopy and piezoresponse force microscopy

In this paper, nanoscale domain patterns of ferroelectric ceramics were investigated by both atomic force acoustic microscopy (AFAM) and piezoresponse force microscopy (PFM). First, we applied the dual frequency resonance tracking (DFRT) technique on AFAM and realized nanoscale modulus mapping. Then we comparatively mapped the nanoscale domain patterns in a PZT ceramics using PFM, single-frequency AFAM, and DFRT AFAM in the same scanning area. Results show that PFM can give the best contrast domain patterns and is not sensitive to cantilever stiffness. In comparison, both modes of AFAM are sensitive to cantilever stiffness and can give good contrast of domains only using very stiff cantilevers. Furthermore, both modes of AFAM can map the subsurface domain structures and the grain boundaries clearly while PFM usually cannot. Based on the resonance-frequency image obtained by the DFRT AFAM, we also obtained the nanoscale modulus of the whole scanning area which may help understand the possible domain movement under mechanical or electric fields. Finally, we suggest that, to characterize the nanoscale domain properties in ferroelectrics, PFM plus resonance tracking AFAM is the best choice. (C) 2013 AIP Publishing LLC