The Influence of Electric and Magnetic Fields on Microstructure in Multiferroic Composite Materials - a Phase-Field-Crystal Approach

利用外加电场和磁场影响多晶材料的微结构的能力在微结构工程中具有潜在的应用。为了探索这种潜力，并了解电磁场和固态物质传输之间的复杂相互作用，我们考虑一个相场晶体（PFC）模型，捕获多铁性复合材料的磁和电晶体相互作用的基本物理。在第一个创建阶段，我们集中在两个方面：首先是PFC模型中磁场的影响，以了解基本现象，其次是PFC模型的粗粒化，以实现幅度扩展（APFC）模型，以实现3D模拟。我们将把这两种方法结合在一起，并逐步添加额外的功能，直到我们到达一个多铁性复合（A）PFC模型。与高效和可扩展的数值算法一起，这将允许2D和3D模拟，这将用于研究外部电场和磁场对扩散时间尺度上缺陷结构和晶界演变的作用。2D和3D中的大规模模拟还将允许获得关于在外部场的影响下的晶粒生长的统计数据，并利用实验数据进行验证，例如，在SPP 1959的其他项目中分析的薄膜铁样品。

The ability to use external electric and magnetic fields to influence the microstructure in polycrystalline materials has potential applications in microstructural engineering. To explore this potential and to understand the complex interactions between electromagnetic fields and solid-state matter transport we consider a phase-field-crystal (PFC) model that captures the basic physics of magneto- and electrocrystalline interactions for multiferroic composite materials. In the first founding period we have concentrated on two aspects: first the influence of magnetic fields in the PFC model, to understand the basic phenomena and second a coarse graining of the PFC model towards an amplitude expansion (APFC) model to enable 3D simulations. We will bring both approaches together and add additional features step by step until we arrive at a multiferroic composite (A)PFC model. Together with efficient and scalable numerical algorithms this will allow 2D and 3D simulations, which will be used to examine the role of external electric and magnetic fields on the evolution of defect structures and grain boundaries, on diffusion time scales. Large scale simulations in 2D and 3D will also allow to obtain statistical data on grain growth under the influence of external fields and to validate with experimental data, e.g., thin film iron samples analyzed in other projects of the SPP1959.