Effect of electrical treatment on the polarization of modified PbTiO3 thin films

Hysteresis loops have been traced and switching currents have been measured in Ca-substituted PbTiO3 thin films prepared by a sol-gel method, deposited by spin coating on Pt/TiO2/SiO2/(100)Si, and thermally treated with different heating rates. The enhancing effect on the hysteresis loops and the switching currents of the previous application of an electric signal is remarkable. On the other hand, remanent polarization and the switching time deduced from switching currents show a strong dependence on the time elapsed after the treatment. The experimental results may be explained by the existence of defects originated during the thermal processing, and their redistribution due to the application of a previous sine wave electric signal.