Modeling the paraelectric aging effect in the acceptor doped perovskite ferroelectrics: role of oxygen vacancy

Abstract

The time dependence of physical properties in the paraelectric phase was probed recently in a Mn(3+) doped (Ba0.8Sr0.2)TiO3 ceramic, providing a simple situation (without spontaneous polarization or domain walls) to quantify the role of the oxygen vacancy during aging. In the present study, we propose a quantitative model for paraelectric aging to understand how the distribution of the oxygen vacancy evolves with time and consequently influences the dielectric response of the paraelectric phase. First, by comparing dielectric behavior of paraelectric aging in a Mn(3+) doped (Ba0.75Sr0.25)TiO3 ceramic and the dielectric tunable effect, an internal bias field E(in) related to the oxygen vacancy is shown to exist in the paraelectric phase. Second, by introducing such a time dependent E(in) in a Landau-type model, we reproduce the dielectric response of Mn(3+) doped (Ba0.8Sr0.2)TiO3 ceramic during paraelectric aging. It is suggested that the increase of dielectric permittivity can be ascribed to the decrease of E(in) with time. The investigation of paraelectric aging is helpful for understanding the role of the oxygen vacancy in influencing the physical properties of ferroelectric materials.

Large activation energy in aged Mn-doped Sr0.4Ba0.6Nb2O6 ferroelectric ceramics

“…In addition, because the models interpreting the aging process is still under debate, the oxygen vacancy also may move a long distance to domain walls in the domain boundary model. 18,52 This different migration path of oxygen vacancy might be the explanation for the larger activation energy in SBN.…”

Giant electrostrain accompanying structural evolution in lead-free NBT-based piezoceramics

“…47 Based on the Landau-Devonshire theory, the free energy (F) of the states without and with defects can be described by Landau polynomials: F=αP 2 +βP 4 +γP 6 , the state without defects where α, β and γ are expansion factors, E d is the local defect field caused by V A and V O , P is the order parameter, i.e., the spontaneous polarization. [48][49][50] Fig. 8(c) and (d) present the schematic Landau free energy with respect to the polarization for the states without and with defects, respectively.…”

“…48,51 Furthermore, the introduced local defects possess the lowest potential barrier and the free energy of material system can be effectively lowered. [47][48][49][50]53 The existence of these local defects can facilitate the growth of ferroelectric domains under a given external field. [47][48][49][50]53 These synergistic contributions help reduce the electric-field required to trigger the formation of long-range polar phase and also the giant electrostrain in SBT5 composition.…”

Rapid stability of ferroelectric polarization in the Ca, Ce hybrid doped BaTiO3 ceramics

“…However, for the application of ferroelectric materials, most of these physical properties are subjected to changes with time (namely aging effect)5. On one hand, the aging effect is one of the most ineluctable obstacles to the reliability and stability of ferroelectric materials, because the properties like polarization reduces over time567. On the other hand, some studies on the aging behaviour have also found that the utilization of the aging effect can lead to a very large recoverable electro-strain891011.…”

“…Many researchers dedicate to study the lead zirconate titanate (PZT) family1215, the barium titanate (BT) family689131416171819202122 and some other lead-free compositions23 to develop reasonable theories to explain the aging phenomenon. There are three theories that have been proposed: grain boundary effect, domain wall effect and volume effect58.…”