EXPERIMENTAL-STUDY AND MODELING OF SWITCHING PROCESSES IN FERROELECTRIC THIN-FILMS

An impact of different factors on the shape of dielectric hysteresis l oop in ferroelectric thin films is discussed. The factors include: pol ycrystallinity and disorientation of polarization directions, polariza tion nonuniformity and depolarization fields, contact potential differ ence and interaction of volume impurity centers with polarization fiel d. A comparison between model conclusions and experimental data show t hat with account of the interaction between polarization and internal electric field one can explain the nature of all main distortions of t he dielectric hysteresis loop in thin films at realistic parameters of the layers. The results obtained permit to explain the distortions pe culiar to real hysteresis loops and also to obtain quality parameters of the samples, which are important for making improvement in the film preparation techniques.