Modeling of the evolution of dielectric loss with processing temperature in ferroelectric and dielectric thin oxide films

Abstract

It was experimentally found that the evolution of dielectric loss with processing temperature displays a common trend in ferroelectric and dielectric thin oxide films: firstly an increase and then a decrease in dielectric loss when the processing temperature is gradually raised. Such a dielectric response of ferroelectric/dielectric thin films has been theoretically addressed in this work. We propose that at the initial stage of the crystallization process in thin films, the transformation from amorphous to crystalline phase should increase substantially the dielectric loss; then, with further increase in the processing temperature, the coalescent growth of small crystalline grains into big ones could be helpful in reducing the dielectric loss by lowering grain boundary densities. The obtained experimental data for (Ba,Sr)TiO 3 thin films with 500 nm in thickness were analyzed in terms of the model developed and shown to be in a reasonable agreement with the theoretical results. a)

Thermal Annealing Effect on the Structure, Optical and Electrical Properties of Lanthanum Manganite Thin Films Prepared by Reactive Co-Sputtering

“…This polycrystallinity could explain the drop of the dielectric constant. These results agree with what has been observed and modeled for ferroelectric (Ba,Sr)TiO 3 thin films and pyrochlore-type Pb(Mg,Nb,Ti)O 3 dielectric films [30].…”

Impedance spectroscopic and dielectric analysis of Ba0.7Sr0.3TiO3 thin films

“…Thin films of Ba0.7Sr0.3TiO3 with a thickness of 500 nm were deposited on Pt/TiO2/SiO2/Si (1 0 0) substrates by ion beam sputtering from a single stoichiometric target [12]. After deposition, the films were then post annealed at Ta = 700 • C for 30 min in a conventional furnace in air ambient.…”

Modeling of enhanced electrocaloric effect above the Curie temperature in relaxor ferroelectrics

“…To address these concerns, theoretical investigations beyond the 4 above-discussed Maxwell relation and classic phenomenological thermodynamics are required. It should be emphasized that the "demon energy" employed in first-principlesbased atomistic simulations, which governs the effective entropy change associated with a variation in the electric field [7,8], excludes the influence of dielectric permittivity, whose dispersion with temperature has been found to have a strong influence on the calculated EC entropy conversion [22]. Most recently, Valent et al [5] investigated the EC effect using a lattice model developed based on the mean-field theory.…”