Controlling the Behavior of Ferroelectric Materials through Strain Engineering

通过应变工程控制铁电材料的行为

• 批准号: 1434147
• 负责人: Nadya Mason
• 金额: $ 51万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1434147&HistoricalAwards=false
• 关键词: Controlling; Behavior; Ferroelectric; Materials; through

Society and industry are increasingly calling upon novel materials to enable new capabilities and new applications. One example of a class of materials that is growing in terms of its use and technological impact are ferroelectric materials. These materials can produce a voltage or electric current when subjected to force (i.e., when compressed or bent) or vice-versa, they can produce movement when a voltage is applied to them. Ferroelectric materials are already utilized in a wide array of applications ranging from positioning systems (e.g., movement of the tips on atomic force microscopes) to energy harvesting (e.g., producing electric current from shoes during walking). This project will explore new ways to control the behavior and properties of ferroelectric materials by developing new materials, referred to here as flexoelectric materials, that are ferroelectric and that are made using modern material deposition methods which produce materials that have varying amounts of atomic level strain (i.e., deformation) built into them. In other words, by depositing the materials in a very controlled way, the normal distances between atoms in the material can be changed in a desired way and this displacement of atoms from their normal equilibrium will result in changes in the material properties. The project will train the next generation of scientists and engineers who can function in a multi-disciplinary team environment and will broadly enhance the infrastructure in the United States as it pertains to the synthesis and fabrication of complex materials. The project will also utilize education and outreach programs that are designed to broaden the participation of underrepresented minorities in science and engineering. The goal of the project is to develop new insights into how inhomogeneous strains (such as strain gradients) can be produced and used to control flexoelectric materials. In particular, scientific framework will be developed to utilize modern thin-film deposition and processing routes to expand the fundamental understanding and utilization of flexoelectric effects (the coupling between a strain gradient and electric polarization). The project will explore the nature and limits of flexoelectricity in ferroelectrics by combining design, synthesis, processing, and characterization of materials. In situ and ex situ processing methodologies will be developed to produce large and tunable inhomogeneous strains (i.e., strain gradients) via the fabrication of flexible and free-standing ferroelectric films. The program will answer two central questions: 1) how can large and deterministic strain gradients be produced, and 2) how does the presence of a large strain gradient impact the field, stress, and temperature susceptibilities of a ferroelectric material? In situ synthesis of large strain gradients in films via the production of compositional and defect gradients will be explored. Ex situ fabrication and processing methods to produce large strain gradients in substrate-supported materials will be explored, together with released and free-standing versions of materials, and the evolution of properties in materials with large strain gradients. This work will impact the fields of ferroic materials, including ferroelectric-based properties, and will have has direct impact on devices that utilize ferroelectrics including memory and logic, sensors and actuators, thermal and energy conversion applications.

社会和工业越来越需要新材料来实现新的功能和新的应用。在其使用和技术影响方面正在增长的一类材料的一个例子是铁电材料。这些材料在受到力时可以产生电压或电流（即，当被压缩或弯曲时），或者反之亦然，当向它们施加电压时，它们可以产生运动。 铁电材料已经用于从定位系统（例如，原子力显微镜上尖端的移动）到能量收集（例如，在行走过程中从鞋中产生电流）。 该项目将探索通过开发新材料来控制铁电材料的行为和特性的新方法，在此称为挠曲电材料，其是铁电的并且使用现代材料沉积方法制成，该方法产生具有不同原子级应变量的材料（即，变形）内置于其中。 换句话说，通过以非常受控的方式沉积材料，材料中原子之间的正常距离可以以期望的方式改变，并且原子从其正常平衡的这种位移将导致材料性质的变化。 该项目将培养下一代科学家和工程师，他们可以在多学科团队环境中发挥作用，并将广泛加强美国的基础设施，因为它涉及复杂材料的合成和制造。 该项目还将利用教育和外联方案，旨在扩大代表性不足的少数民族在科学和工程领域的参与。该项目的目标是开发新的见解，了解如何产生不均匀的应变（如应变梯度），并用于控制挠曲电材料。特别是，将开发科学框架，利用现代薄膜沉积和加工路线，扩大对挠曲电效应（应变梯度和电极化之间的耦合）的基本理解和利用。 该项目将通过结合材料的设计、合成、加工和表征来探索铁电体中挠曲电性的性质和限制。将开发原位和非原位处理方法以产生大的和可调的非均匀应变（即，应变梯度）。该计划将回答两个核心问题：1）如何产生大的和确定性的应变梯度，以及2）大应变梯度的存在如何影响铁电材料的场，应力和温度敏感性？将探讨通过产生成分和缺陷梯度在膜中原位合成大应变梯度。 将探索在衬底支撑材料中产生大应变梯度的非原位制造和加工方法，以及材料的释放和独立版本，以及具有大应变梯度的材料的性能演变。这项工作将影响铁电材料的领域，包括基于铁电的特性，并将对利用铁电材料的设备产生直接影响，包括存储器和逻辑，传感器和致动器，热和能量转换应用。