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

Abstract

AbstractBismuth 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.