Effect of Grain Size on Effective Permittivity of Ferroelectric Films Based on Effective Medium Theory

Abstract

Based on effective medium theory, the temperature dependence of effective dielectric permittivity, εe(T), on core radius (a) and thickness (t) of non-ferroelectric dead layer (DL) on the surface of inhomogeneous grains of ferroelectric film made up of cylindrical ferroelectric grains was theoretically investigated. It was found that εe(T) increases with increasing core radius but decreases with increasing DL thickness. In this work, an equation expressing the relationship among εe, a and t was derived. This equation is very useful for the preparation of a ferroelectric film to desired properties.