Ferroic Domain Dynamics by In-Situ Transmission Electron Microscopy Techniques

原位透射电子显微镜技术的铁磁畴动力学

• 批准号: 2281587
• 金额: --
• 依托单位: Queen's University Belfast
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2281587
• 关键词: Ferroic; Domain; Dynamics; Situ; Transmission

Ferroic materials are routinely being used as key components for a wide variety of devices, such as sensors and actuators, and are particularly promising for devices such as memories and resistors. Ferroics' key characteristics are the development of equivalent ground states, known as domains that form to minimise the system's free energy. In general, domains appear after the material undergoes a ferroic phase transition, which have their origins in structural shear (ferroelastics), or electrical dipole moments (ferroelectrics). The reversible switching of domains is what ultimately enables ferroics' functionality.All domains are physically separated by domain walls (DWs) which can have dimensions in the nanoscale regime. It has been shown that these interfaces exhibit novel properties, and are the active element in the ferroic material (instead of the bulk itself), making them especially attractive for nano-electronics. This, along the current trend on device miniaturisation, has brought a new area of research focused on domain engineering, where the functional properties of ferroics can be tuned by modifying the geometry, strain or electrical landscape. Examples of technologies that could directly benefit from a more comprehensive understanding and control over domains and domain boundaries are memory devices and optical and sonar detectors.The aims of this project are two-fold, a) to obtain a deeper understanding of domain dynamics in ferroelastic domains at the micro and nanoscale as a function of applying external stimuli (temperature and strain) and b) to create novel configurations that will allow deterministic control of the ferroelastic domains (injection and subsequent motion). The latter will involve the creation of device-like structures, where strain will be introduced via biasing of a piezoelectric layer. The piezoelectric material will transfer the necessary strain to the ferroelastic sample for domain motion.A substantial part of this project involves the development of sample preparation techniques, especially by Focused ion beam. The project will use in-situ TEM heating and biasing carried out in combination with other microscopy techniques such as atomic force microscopy to image and probe domain motion.This project and its aims, represent a unique opportunity to study fundamental aspects of ferroelastic domains, along with device-like samples that will provide a different insight for future devices, in particular, for electronic applications.Areas considered relevant to the project;- Materials Characterisation- Condensed Matter Physics

铁基材料通常被用作传感器和致动器等各种器件的关键部件，并且特别有希望用于存储器和电阻器等器件。铁电体的关键特征是发展出等效基态，即所谓的畴，它的形成使系统的自由能最小化。一般来说，畴在材料经历铁性相变之后出现，其起源于结构剪切（铁弹性）或电偶极矩（铁电体）。畴的可逆转换是铁电体功能的最终实现。所有的畴都被畴壁（DW）物理地分隔开，畴壁可以具有纳米级的尺寸。已经表明，这些界面具有新颖的特性，并且是铁性材料中的活性元素（而不是块体本身），使它们对纳米电子学特别有吸引力。这一点，沿着当前的趋势，对设备封装，带来了一个新的研究领域，重点是域工程，其中铁性材料的功能特性可以通过修改的几何形状，应变或电气景观进行调整。可以直接受益于对域和域边界更全面的理解和控制的技术示例包括存储设备以及光学和声纳检测器。该项目的目标有两个方面，a）更深入地了解微纳米级铁弹畴中畴动力学随外部刺激的变化（温度和应变）和B）以产生将允许铁弹域的确定性控制（注入和随后的运动）的新颖配置。后者将涉及创建类似器件的结构，其中应变将通过压电层的偏置引入。压电材料将把必要的应变传递给铁弹样品以实现磁畴运动。本项目的一个重要部分涉及样品制备技术的发展，特别是聚焦离子束。该项目将使用原位TEM加热和偏置，并结合其他显微镜技术（如原子力显微镜）来成像和探测畴运动。该项目及其目标代表了一个独特的机会，可以研究铁弹畴的基本方面，沿着类似器件的样品，这将为未来的器件提供不同的见解，特别是，电子应用。与项目相关的领域;-材料特性-凝聚态物理