Abstract In this study, electromechanical responses of BiFeO 3 /BaTiO 3 (BFO/BTO) (0-3) nanocomposites with different volume fractions of BFO nanoparticles are investigated using phase field model based on the Landau-Ginzburg theory. A rich phase coexistence, including tetragonal ( T ), orthorhombic ( O ), and rhombohedral ( R ) phases, is characteristically formed in the domain structure of the nanocomposite due to interactions between BFO nanoparticles and BTO matrix through the interfaces. In particular, the O and R phases emerged in the original T -BTO matrix arises from the disruption of long-range R phase in BFO nanoparticles and high strain near the interfaces. The coexistence of multiphases generates high densities of domain walls and triple junctions of multiphase domains, which make polarization field more susceptible to an external strain. As a result, an anomalously large piezoelectric response is found in the BFO/BTO (0-3) nanocomposites. We further demonstrate that the direct piezoelectric effect is strongly dependent of the volume fraction of constituent phases, suggesting a route for the rational design of polarization domains and piezoelectric effects.

中文翻译：

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(0-3) 多相共存无铅铁电纳米复合材料的机电性能增强

摘要 本研究利用基于Landau-Ginzburg 理论的相场模型研究了具有不同体积分数的BFO 纳米颗粒的BiFeO 3 /BaTiO 3 (BFO/BTO) (0-3) 纳米复合材料的机电响应。由于 BFO 纳米颗粒和 BTO 基质之间通过界面相互作用，在纳米复合材料的域结构中特征性地形成了丰富的相共存，包括四方 ( T )、正交 ( O ) 和菱面体 ( R ) 相。特别是，原始 T-BTO 基质中出现的 O 和 R 相是由于 BFO 纳米粒子中长程 R 相的破坏和界面附近的高应变引起的。多相的共存产生高密度的畴壁和多相畴的三重结，这使得极化场更容易受到外部应变的影响。结果，在 BFO/BTO (0-3) 纳米复合材料中发现了异常大的压电响应。我们进一步证明直接压电效应强烈依赖于组成相的体积分数，这为极化域和压电效应的合理设计提供了一条途径。