Dielectric properties of ferroelectric thin films with surface transition layers

Abstract

By taking into account surface transition layers (STL), the dielectric properties of ferroelectric thin films described by the transverse Ising model are discussed in the framework of the mean field approximation. Functions of the intra-layer and inter-layer couplings are introduced to characterize STL, which makes the model more realistic compared to previous treatment of surface layers using uniform surface exchange interactions and a transverse field. The effects of physical parameters on the dielectric properties are quantified. The results obtained indicate that STL has very strong influence on the dielectric properties of ferroelectric thin films. Some of our theoretical results are in accord with the available experimental data.

Sol-gel Derived (Pb0.65Sr0.35)(Zr0.5, Ti0.5)O3 Ferroelectric Thin Films: Structural and Electrical Properties

“…where ε0 the permittivity of free space, εr dielectric constant of the insulating film, A the area and d the thickness) and loss tangent (𝑡𝑎𝑛𝛿 =    ) was obtained directly from the measurement [9]. The variation of ɛ and tanδ as a function of temperature at different frequencies is shown in the Figure 4.…”

Thermodynamic properties of a quasi-harmonic model for ferroelectric transitions

“…Many theoretical studies have been performed (see e.g. [4][5][6]) where the common merit is the elucidation of the physical properties of ferroelectric materials: investigation of the phase transition mechanisms, physical characteristics and associated peculiarities, explanation of their microscopic origin and nature, and further explanation of other effects such as surface, size, doping, substrate defect effects and bulk behavior [38][39][40][41][42][43][44]. Even though many consistent microscopic theories, interpreting the observed phenomena in terms of microscopic models and atomic interactions, studying the behavior of thermodynamic quantities and clarifying the character of anomalies at the critical points, have been developed, a careful theoretical modeling of the properties of ferroelectrics that helps in the replication/analysis of ferroelectric phase transitions within a single model parameters approach has not yet been developed.…”

Polarization Properties of Ferroelectric Thin Films Under Different Boundary Conditions

“…[23][24][25][26] Considering the multilayer structures of surface layers, we have introduced a different film design to describe the STL in Ref. 27, which investigates the role of the intra-layer (within layer) and inter-layer (across layers) interactions (J a (m) and J e (m) as shown in Fig. 1) between two pseudo-spins in the formation of dielectric properties of ferroelectric thin films.…”