Converse Transduction in the Presence of Strong Electrical Field Gradients in Ferroelectrics (ConTraGrad)

铁电体强电场梯度下的逆传导 (ConTraGrad)

• 批准号: 391065131
• 负责人: Professor Dr.-Ing. Marc Kamlah
• 金额: --
• 依托单位: Professur für Mikrostrukturierte Mechatronische Systeme
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/391065131?language=en
• 关键词: Converse; Transduction; Presence; Strong; Electrical

The overall objective of this project is gaining a deeper insight into the behavior of the ferroelectric class of piezoelectric materials when subject to high electric fields and strong electrical gradients covering both, the piezoelectric and flexoelectric effects. Flexoelectricity refers to the electromechanical coupling between the mechanical strain gradient and the electrical polarization in a dielectric. Recently, more and more interest in scientific research has been shifted towards flexoelectricity in ferroelectrics. The investigation will be executed as collaboration between the Technische Universität München (TUM) and the Karlsruhe Institute of Technology (KIT). The TUM group will mainly be responsible for performing the experimental investigations while the KIT group will be working on the theoretical investigation, i.e. modeling and simulation. The objectives and the work will be organized in two parts. The first objective, primarily related to the occurrence of high electric fields, is to study actuators with singlesided interdigitated electrode (IDE)-patterns by means of a theory for large signal hysteresis behavior in view of understanding and optimizing the actuator deformation after poling, as well as investigating the actuation potential with special consideration ofpossible piezoelectric non-linearity. The second objective, related to strong electrical gradients in the first place, concerns the converse flexoelectric effect. For the actuators with single sided IDE-patterns subject of this proposal, this involves investigating the relevance of the converse flexoelectric effect on one side and understanding thecontribution of the converse flexoelectric effect to the actuation behavior on the other. The application of strong electrical gradients is expected to lead to new types of behavior. In view of the above objectives, we propose to study: 1) piezoelectric non-linearity: frozen domains within the material become mobile (i.e. usable), in effectincreasing the magnitude of the piezoelectric coefficients. 2) converse flexoelectricity: strong non-uniform electric fields with pronounced gradients lead to activating the converse flexoelectric effect. 3) piezoelectric-flexoelectric coupling: information on the interplay between the two effects is currently quasi non-existent. The knowledge gained from this project has important practical consequences. For instance, it might enable realization of fail-safe actuators that function in temperatures that exceed the Curietemperature of piezoelectric ceramics. The actuators can then serve as the active components for devices in extreme environments.

该项目的总体目标是更深入地了解铁电类压电材料在高电场和强电场梯度下的行为，压电效应和挠曲电效应是指机械应变之间的机电耦合。最近，越来越多的科学研究兴趣转向了铁电体的弯曲电性，这项研究将通过 Technische 之间的合作进行。慕尼黑大学（TUM）和卡尔斯鲁厄理工学院（KIT）将主要负责进行实验研究，而 KIT 小组将致力于理论研究，即建模和模拟工作。第一个目标主要与高电场的发生有关，是通过大信号滞后理论来研究具有单面叉指电极（IDE）图案的执行器。考虑到理解和优化极化后的致动器变形，以及特别考虑可能的压电非线性来研究致动电位，第二个目标首先与强电梯度相关，涉及逆挠曲电效应。对于本提案主题的具有单面 IDE 模式的执行器，这涉及研究一侧的逆挠曲电效应的相关性并了解逆挠曲电效应的贡献另一方面，强电梯度的应用预计会导致新类型的行为。鉴于上述目标，我们建议研究：1）压电非线性：材料内的冻结域。变得可移动（即可用），实际上增加了压电系数的大小2）逆挠曲电：具有明显梯度的强非均匀电场导致激活逆挠电。 3）压电-挠电耦合：目前几乎不存在有关两种效应之间相互作用的信息，例如，它可能有助于实现具有功能的故障安全执行器。在超过压电陶瓷居里温度的温度下，执行器可以作为极端环境下设备的有源组件。