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A three-dimensional multiscale peridynamics model for Ferroelectric/Multiferroic Tunnel Junctions

铁电/多铁隧道结的三维多尺度近场动力学模型

基本信息

批准号：
286791468
负责人：
Professor Dr.-Ing. Timon Rabczuk, Ph.D.
金额：
--
依托单位：
Institut für Strukturmechanik (ISM)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/286791468?language=en
关键词：
three dimensional multiscale peridynamics model

项目摘要

In this project, a three-dimensional multiscale peridynamics (PD) model for fracture in ferroelectric/multiferroic tunnel junctions is proposed. A ferroelectric tunnel junction (FTJ) is a ferroelectric sandwich layer used as a barrier material between electrodes for tunneling of electrones. By using ferromagnetic electrodes the functionality of FTJs can be extended to create multiferroic tunnel junctions (MTJs). FTJs/MTJs have been widely used in electronic devices such as ferroelectric memories, microsystems, tunable microwaves, binary data storage, ferroelectric random access memories (FRAMs), among others. Fracture in FTJ/MTJs can influence their reliability. For instance, it might lead to the reduction of the electric field seen by the ferroelectric thin-film. One popular fracture mechanism in ferroelectric thin-films is caused by the polarization switching and results in a systematic loss of the remanent switchable polarization as a function of the number of bipolar switching cycles. A molecular dynamics (MD) model for FTJ/MTJs should be devised at the fine scale while a state-based thermomechanical-electromagnetic PD continuum model needs to be developed at the coarse-scale. The transfer of length scales is accomplished through higher order gradient (HOG) models of the PD and the MD models so that they show the same dynamic dispersion. The advantage of the PD model over existing models such as XFEM is its ease in handling discontinuities as they are a natural outcome of the analysis. No representation of the crack topology is needed. Moreover, due to the non-local character of the PD model, it can be coupled to the MD model in a more natural way. The approach will be verified and validated by comparison to available experimental data and used in order to answer some urgent questions related to the fracture behavior in FTJ/MTJs.

在本项目中，提出了铁电/多铁隧道结断裂的三维多尺度周期动力学模型。铁电隧道结(FTJ)是一种铁电夹层，用作电极之间的势垒材料，用于电子的隧道传输。通过使用铁磁电极，FTJ的功能可以被扩展以创建多铁隧道结(MTJ)。FTJ/MTJ已广泛应用于铁电存储器、微系统、可调谐微波、二进制数据存储、铁电随机存取存储器等电子器件中。FTJ/MTJ的断裂会影响其可靠性。例如，它可能会导致铁电薄膜所看到的电场的减小。铁电薄膜中一种常见的断裂机制是由极化转换引起的，并导致剩余的可转换极化作为双极转换循环次数的函数的系统损失。FTJ/MTJ的分子动力学模型需要在精细尺度上建立，而基于状态的热力-电磁局部放电连续介质模型则需要在粗尺度上建立。长度尺度的传递是通过PD模型和MD模型的高阶梯度(HOG)模型来完成的，因此它们表现出相同的动态色散。PD模型相对于现有模型(如XFE)的优势在于，它易于处理不连续，因为它们是分析的自然结果。不需要裂纹拓扑的表示。此外，由于PD模型的非局部性，它可以更自然地耦合到MD模型。该方法将通过与现有实验数据的比较来验证和验证，并用于回答与FTJ/MTJ断裂行为有关的一些紧迫问题。