Theoretical Study On Size Effects Of The Phase Transition And Dielectric Properties In Quasi-low Dimensional Ferroelectric Materials

due to their excellent ferroelectric, piezoelectric, dielectric and pyroelectric properties, and wide applications in many fields. With the development of the modern techniques and the extensive application of functional devices made up of FE materials, size effects on ferroelectricity have aroused great interest due to the miniaturization and integration requirement of the microelectronic industry. In this dissertation, based on the Landau thermodynamic theory and the transverse Ising model, from the macroscopic and microcosmic views, we theoretically studied the size effect on the phase transition behaviors and dielectric properties of the low dimensional FE materials, such as FE thin films, FE nano ceramics and FE particles. The main work and results are as follows:1. Many surface factors, such as impurities, defects, interfacial stress, the electrode and substrate used, can lead to the existence of the imperfect layers near the FE thin film surface region. The larger imperfect surface layer to volume ratio...