Preparation and characterization of piezoelectric (Pb0.76Ca0.24)TiO3 films

Tetragonal (Pb_0.76Ca_0.24)TiO₃ thin films have been prepared on Pt-Ti-SiO₂-Si substrates using sol-gel processing. Besides XRD, SEM and AFM characterization, ferroelectric hysteresis loop and dielectric measurements were used to characterize the electric properties. Piezoelectric-mode AFM was also used to investigate local ferroelectric switching. Experimental results show that the films are pure perovskite with a dense structure and small surface roughness. A high contrast in ferroelectric switching image was obtained. This is attributed to the large electrostriction coefficient and weak clamping effect from the substrate which is related with high piezoelectric anisotropy of this material. The discrepancy between the values of coercive fields from micro and macro measurement is attributed to the nonuniform distribution of electric field in the film in local measurement