Ferroelectric ceramics have the potential to be widely applied in the modern industry and military power systems due to their ultrafast charging/discharging speed and high energy density. Considering the structural design and electrical properties of ferroelectric capacitor, it is still a challenge to find out the optimal energy storage of ferroelectric ceramics during the phase-transition process of amorphous/nanocrystalline and polycrystalline. In this work, a finite element model suitable for the multiphase ceramic system is constructed based on the phase field breakdown theory. The nonlinear coupling relationship of multiple physical fields between multiphase ceramics was taken into account in this model. The basic structures of multiphase ceramics are generated by using the Voronoi diagram construction method. The specified structure of multiphase ceramics in the phase-transition process of amorphous/nanocrystalline and polycrystalline was further obtained through the grain boundary diffusion equation. The simulation results show that the multiphase ceramics have an optimal energy storage in the process of amorphous polycrystalline transformation, and the energy storage density reaches the maximum when the crystallinity is 13.96% and the volume fraction of grain is 2.08%. It provides a research plan and idea for revealing the correlation between microstructure and breakdown characteristics of multiphase ceramics. This simulation model realizes the nonlinear coupling of the multiphase ceramic mesoscopic structure and the phase field breakdown. It provides a reference scheme for the structural design and performance optimization of ferroelectric ceramics.

High-density ferroelectric BiFeO₃ (BFO) nanodot arrays were developed through template-assisted tailoring of epitaxial thin films. By combining piezoresponse force microscopy (PFM) and Kelvin probe force microscopy (KPFM) imaging techniques, we found that oxygen vacancies in nanodot arrays can be transported in the presence of an electric field. Besides triple-center domains, quadruple-center domains with different vertical polarizations were also identified. This was confirmed by combining the measurements of the domain switching and polarization vector distribution. The competition between the accumulation of mobile charges, such as oxygen vacancies, on the interface and the geometric constraints of nanodots led to the formation of these topological domain states. These abnormal multi-center topological defect states pave the way for improving the storage density of ferroelectric memory devices.

Two-dimensional α-In₂Se₃ exhibits simultaneous intercorrelated in-plane and out-of-plane polarization, making it a highly promising material for use in memories, synapses, sensors, detectors, and optoelectronic devices. With its narrow bandgap, α-In₂Se₃ is particularly attractive for applications in photodetection. However, relatively little research has been conducted on the out-of-plane photoconductive and bulk photovoltaic effects in α-In₂Se₃. This limits the potential of α-In₂Se₃ in the device innovation and performance modification. Herein, we have developed an α-In₂Se₃-based heterojunction with a transparent electrode of two-dimensional Ta₂NiS₅. The out-of-plane electric field can effectively separate the photo-generated electron–hole pairs in the heterojunction, resulting in an out-of-plane responsivity (R), external quantum efficiency (EQE), and specific detectivity (D*) of 0.78mA/W, 10−3% and 1.14×108 Jones, respectively. The out-of-plane bulk photovoltaic effect has been demonstrated by changes in the short circuit current (SCC) and open circuit voltage (Voc) with different optical power intensity and temperature, which indicates that α-In₂Se₃-based heterojunctions has application potential in mid-far infrared light detection based on its out-of-plane photoconductive and bulk photovoltaic effects. Although the out-of-plane photoconductive and bulk photovoltaic effects are relatively lower than that of traditional materials, the findings pave the way for a better understanding of the out-of-plane characteristics of two-dimensional α-In₂Se₃ and related heterojunctions. Furthermore, the results highlight the application potential of α-In₂Se₃ in low-power device innovation and performance modification.

与传统铁电材料相比，具有准同型相界(MPB)的铁电体具有增强的介电、压电和电光性能。通过传统固相烧结技术获得致密的(1-x)Ba2NaNb5O15-xSr2KNb5O15 (BNN-SKN)钨青铜结构陶瓷二元固溶体系，系统研究了BNN-SKN的结构、介电和铁电性能，探究迄今尚未确定的MPB区域。Ccm2与P4bm共存的MPB在x = 0.7附近，随着SKN含量的增加，所测样品的相变温度及介电常数均在x = 0.7附近取得极值，Tm = 170.1 ℃, eTR= 1 211, em = 3 326，给出了BNN-SKN体系的铁电性能，并讨论了该二元体系铁电性变化的影响因素。

掺杂HfO2铁电薄膜在非易失性存储器件中的重要应用前景使其成为当前凝聚态物理与材料科学领域的一个研究热点。近年来，结果表明：La掺杂HfO2拥有优异的铁电性能，铁电剩余极化强度为45 mC/cm2，是目前HfO2基薄膜材料中报道的最高值。由于Nd与La的化学性质相近，Nd掺杂同样有望增强HfO2的铁电性，但相关研究工作却鲜有报道。使用氧化物分子束外延技术，在La0.67Sr0.33MnO3(底电极)/SrTiO3(001)衬底上外延生长高质量Nd掺杂HfO2(Nd:HfO2)薄膜。X射线衍射以及高分辨电镜表征结果均显示Nd掺杂有助于诱导HfO2从单斜相向正交相的转变，压电力显微镜和铁电测试仪进一步证实正交相Nd:HfO2具有良好的铁电性。此外，高分辨电子显微镜表征还发现Nd:HfO2靠近界面处存在四方相结构，衔接(111)晶向的Nd:HfO2和(001)晶向的钙钛矿氧化物衬底。Nd:HfO2薄膜的外延生长和铁电性的系统研究，扩充了掺杂HfO2的研究体系。

采用丝网印刷工艺在PMNPT弛豫铁电单晶晶片表面涂覆了中温及高温两种银浆，通过快速烧结工艺分别在650和850 ℃条件下制备了银电极。采用扫描电子显微镜观察银电极表面及金属晶体界面的微观结构，采用能谱分析了界面的元素分布情况。银电极厚度为几十微米，呈多孔结构，与晶体结合良好。经过烧结后，晶体中的Pb、Nb、Ti等原子向银电极发生了迁移，而高温银浆烧结后在界面形成几微米厚的过渡层，晶体中原子向电极中的迁移大幅度减少。不同晶向的PMNPT晶片在高温下向银电极扩散过程中具有很强的晶面效应，［110］方向晶体中Pb、Nb、Ti原子向电极中的扩散程度小于［100］方向晶体。

在骨修复领域中，通过构建天然骨再生微环境可加速骨修复进程。细胞微环境中的重要一环是生物电信号，它广泛存在于人体各种组织中，对干细胞分化、组织修复等具有关键调控作用。而电活性材料具有独特的电学特性，因此可借助电活性组织工程材料在骨缺损处模拟再生电学微环境，激发人体固有修复潜力，加速骨缺损的修复。本文根据所应用电学特性的区别，按铁电、压电、驻极效应和导电特性等类型，系统地综述了采用各种类型电活性材料促进骨修复的研究状况，为进一步研究提供了新思路。