Figure 5. (A-C) PFM images with a 3 μm 3 μm region; (D) Average autocorrelation function < C(r) >; (E and F) Amplitude-voltage, phase-voltage, and local piezoresponse loop of the unpoled 0.555PNN-0.145PZ-0.30PT ceramics. PFM: Piezoelectric force microscopy.