Correlation between local hysteresis and crystallite orientation in PZT thin films deposited on Si and MgO substrates

(0 0 1)-Oriented tetragonal ferroelectric PbZr0.53Ti0.47O3 (PZT) thin films (90 nm of thickness) have been grown on TiOx/Pt/TiO2/SiO2/Si and TiOx/Pt/MgO substrates. The existence of (1 0 0)-oriented crystallites in the c-axis matrix of the (0 0 1)-oriented films has been evidenced by using four circles X-ray diffraction. Depending on the substrate, the ratio of the lattice parameters c/a was found to be 1.02 (Si) and 1.07 (MgO) and this was correlated with the coercive field values. Local piezoelectric hysteresis loops produced by atomic force microscopy have been taken with profit to characterize the switching properties of the ferroelectric domains at the scale of individual crystallites. In each case, (1 0 0)-oriented crystallites require much higher voltage than (0 0 1)-oriented crystallites for switching. These results are explained by taking into account the strain imposed by the substrate in the film. We conclude that piezoelectric hysteresis loops produced by atomic force microscopy provide very rich information for addressing the local switching property of individual crystallites in PZT thin films.