Multiple property enhancement in bismuth ferrite‐based ferroelectrics by balancing nanodomain and relaxor state

Abstract

Bismuth ferrite‐barium titanate (BF‐BT)‐based ferroelectrics have received widespread attention due to its adjustable structure features and multifunctional characteristics. Property optimization (ferroelectricity, piezoelectricity, electrostrain, electrostriction) for different application scenarios can be realized by increasing BT content gradually, while it is still difficult to integrate multiple performance advantages in the same component. To solve the problem and achieve the simultaneous enhancement of property parameters, defect engineering was adopted in this work to balance domain configuration and relaxor state via selective oxides modification strategy. Compared with the nanodomain engineered relaxor ferroelectrics with improved electrostrain and degraded ferroelectricity, the defect‐mediated ceramics doped with MnO2 present both enhanced electrostrain and ferroelectricity. Multiscale structure analysis (crystal structure, defect structure, and domain structure) and property characterization (ferroelectricity, strain property, and leakage current density) suggested that the defect dipoles induced by Mn substitution can effectively refine domain size and maintain ferroelectric state at room temperature, and the easier domain switching caused by weak‐correlated polar dipoles greatly improves both the strain and ferroelectricity. Especially, the defect dipoles‐mediated nanodomain and property enhancement can be only observed in BFO‐Mn ceramics, and infeasible for other oxides (e.g., CuO and CeO2). We believe that this work can provide some guidance to modify electrical properties in BF‐BT‐based ferroelectrics.

Constructing Relaxor/Ferroelectric Pseudocomposite To Reveal the Domain Role in Electrostrain of Bismuth Ferrite–Barium Titanate Based Ceramics

“…Previous studies have shown that both ion substitution and the addition of a third constituent can destroy the long-range ferroelectric orders and then obtain a domain size with appropriate miniaturization, resulting in an enhanced electrostrain effect. , Therefore, it seems that the formation of a nanodomain is the key point for improved strain response. However, it should also be noted that even though homogeneously labyrinth-like nanodomain can be formed in MnO 2 modified BF-BT ceramics, the obtained strain is still lower than that in RFE components with grain dependent nanodomain configuration. All these phenomena make the domain conformation, especially the coexistence of grain dependent miniaturized strong and weak piezoresponse domain structures, closely related to the strain behavior in BF-BT-based ceramics.…”

Property Regulation Principle in Mn‐Doped BF–BT Ceramics: Competitive Control of Domain Switching By Defect Dipoles and Domain Configuration

“…The similar miniaturized domain structures have also been observed in 0.5 mol% MnO 2 doped 0.69BF–0.3BT–0.01BZH ceramics. [ 15 ] The difference is that more MnO 2 content needs to be added in this work to realize the nanodomain structure. [ 15 ] This is related to the choice of matrix, the more relaxed the matrix is, the easier it is to induce the emergence of nanodomains.…”

“…[ 15 ] The difference is that more MnO 2 content needs to be added in this work to realize the nanodomain structure. [ 15 ] This is related to the choice of matrix, the more relaxed the matrix is, the easier it is to induce the emergence of nanodomains. On the contrary, the PIN‐PMN‐PT single crystal is in a pure rhombohedral phase with lower structure disorder, thus the domain does not shrink after introducing Mn.…”

“…[ 15 ] Especially, the phenomenon of nanodomain induced by Mn doping in BF–BT relaxor ferroelectrics is opposite to that found in Mn‐doped PIN‐PMN‐PT relaxor single crystal, where enlarged domain size can be observed. [ 17 ] Although the phenomenon of domain size refinement by Mn doping has been reported in our previous work, [ 15 ] there are still some open questions needs to be answer. First, what are the reasons for the formation of nanodomain and why they are inconsistent with the Mn‐doped PIN‐PMN‐PT single crystal.…”

Controlling the domain size to enhance the piezoelectricity of BiFeO3–BaTiO3via heterovalent doping

“…It is mostly owing to the fact that an increase in density benets leakage current reduction, but a drop in density degrades piezoelectric characteristics. 49 Thermal stability…”