Effect of crystallographic orientation on ferroelectric properties of PbZr0.2Ti0.8O3 thin films

We report on the effect of cooling rate on the crystallographic orientation and ferroelectric properties of PbZr0.2Ti0.8O3 (PZT) thin films grown on a lattice matched bottom electrode such as c-axis oriented Y-Ba-Cu-O (YBCO). The cooling rate from deposition temperature influences the crystallographic orientation of the ferroelectric c axis of the PZT film as well as the electrical properties of the YBCO bottom electrode. As the volume fraction of the ferroelectric phase with the c axis in the plane of the film becomes higher, the hysteresis loops become more rounded and the polarization values become smaller. Highly c-axis oriented films, obtained by cooling from the growth temperature at 20°C/min, show an almost square hysteresis loop with the largest polarization values.