Investigation of the ferroelectric domain dynamics and its effects on macroscopic behaviors using a synchrotron X-ray photon correlation spectroscopy

使用同步加速器 X 射线光子相关光谱研究铁电畴动力学及其对宏观行为的影响

• 批准号: 2309184
• 负责人: Jong Ryu
• 金额: $ 18万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2309184&HistoricalAwards=false
• 关键词: Investigation; ferroelectric; domain; dynamics; its

NON-TECHNICAL SUMMARYFerroelectric (FE) materials show spontaneous polarization that can be switched by an electric field. These materials consist of domains, the regions where the polarization is oriented in the same directions. FE materials have been used in various electronic devices such as infrared sensors, actuators, and ultrasound transducers. While it is well recognized that the modification of the domain configurations can enhance the electromechanical and dielectric properties of the FE materials, there is a knowledge gap regarding what is the ideal domain size or domain wall density (i.e., boundary regions between adjacent domains) to optimize the macroscopic material properties. The proposed research aims to develop an in-situ characterization method based on the X-ray photon correlation spectroscopy (XPCS). XPCS can investigate the dynamics of the atomic structures of materials over a range of time from milliseconds to hundreds of seconds in the mesoscale length (1 to tens of micrometers). This range is a critical to explaining the effect of atomistic phenomena on the macroscopic behavior and not efficiently accessible by the current existing techniques, such as X-ray diffraction and piezoresponse force microscopy. The newly proposed method compares the shift of X-ray images under applied electric field. The degree of shift will be statistically analyzed to reveal the mechanisms for electromechanical response in the material, including through continuous domain deformation or discrete domain wall motion. The outcome of this research will be a proof-of-concept of the viability of the above approach for further investigations of the effects of domain wall density and domain size on the FE material properties. Additionally, this proposal includes educational plans aimed at promoting STEM careers among underrepresented minority (URM) groups. These plans involve K-12 outreach initiatives, integrating STEM curriculum for university students, and providing research mentorship to high school and college students from URM groups.TECHNICAL SUMMARYThe proposed research aims to investigate the fundamental mechanisms behind the ferroelectric (FE) domain engineering through proof-of-concept research distinguishing X-ray scattering behaviors associated with the intrinsic (i.e., domain extension and dipole rotation) and extrinsic (i.e., discrete domain wall motion) contributions to the electromechanical (i.e., piezoelectric) response. The proposed approach by X-ray photon correlation spectroscopy (XPCS) provides a fundamentally new method to investigate the domain and domain wall effects in the mesoscopic (one to tens of microns) range, which is a critical length scale explaining the effect of atomistic phenomena on the macroscopic material behavior. For comparison, the existing techniques based on X-ray diffraction can estimate domain switching on a macroscopic scale, by using the relative intensity of the corresponding diffraction peak. Furthermore, the theoretical estimation is limited to the domain configuration that can be perfectly described by the diffraction peaks used in the calculation. Similarly, while piezoresponse force microscopy can visualize FE domain patterns, it is difficult to characterize the dynamic atomic structure changes at the mesoscale, due to the scanning speed limitations. In contrast, XPCS acquires the scattering signals in a frame to track the pattern shift in all locations over milliseconds to hundreds of seconds. This project will use Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals to test if the statistical distributions of the XPCS decorrelation functions can distinguish between the effects of intrinsic and extrinsic responses. The goal is to develop a 'two-field' XPCS method and a statistical analysis tool for assessing the contributions of intrinsic and extrinsic mechanisms to the piezoelectric and dielectric properties. This project also aims to educate the next generation of engineers and scientists through multidisciplinary research involving materials science, X-ray characterization, and data science. The research outcome will be also used to educate K-12, undergraduate, as well as graduate-level students from underrepresented minority groups through various initiatives, such as outreach activities and innovative curricular efforts.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要（FE）材料显示自发极化，可以通过电场切换。这些材料由域组成，域，偏振的区域以相同的方向为导向。 FE材料已用于各种电子设备，例如红外传感器，执行器和超声传感器。虽然众所周知，域配置的修改可以增强Fe材料的机电和介电特性，但关于理想的域大小或域壁密度（即相邻域之间的边界区域）是什么是知识差距，以优化宏观的材料。拟议的研究旨在基于X射线光子相关光谱（XPC）开发一种原位表征方法。 XPC可以在中尺度长度（1至几十微米）的一段时间内研究材料原子结构的动力学。该范围对于解释原子现象对宏观行为的影响至关重要，而不是通过当前现有技术（例如X射线衍射和Piezoresponse Force显微镜）有效访问的范围。新提出的方法比较了在应用电场下X射线图像的移位。统计分析的移位程度将揭示材料中机电响应的机制，包括通过连续域变形或离散域壁运动。这项研究的结果将是上述方法可行性的概念，以进一步研究域壁密度和域大小对FE材料特性的影响。此外，该提案还包括旨在促进代表性不足的少数民族（URM）群体中的STEM职业的教育计划。这些计划涉及K-12涉及宣传计划，为大学生的STEM课程整合，并为来自URM Group的高中和大学生提供研究指导。技术总结旨在研究拟议的研究旨在研究铁电（FE）域工程背后的基本机制，通过量身定向研究通过与X-Ray的行为进行了与X-RAY的行为相关联（I.外部（即离散域壁运动）对机电（即压电）响应的贡献。 X射线光子相关光谱（XPC）提出的方法提供了一种从根本上进行研究，以研究介质（一个至数十万微米）范围的域和域壁效应，这是一个临界长度尺度，解释了原子现象对宏观材料行为的影响。为了进行比较，基于X射线衍射的现有技术可以通过使用相应的衍射峰的相对强度来估计宏观尺度上的域切换。此外，理论估计仅限于域构型，该域配置可以由计算中使用的衍射峰完美地描述。同样，虽然压电力显微镜可以可视化Fe结构域模式，但由于扫描速度限制，很难表征中尺度上的动态原子结构变化。相比之下，XPC在框架中获取散射信号，以跟踪所有位置的模式移动，以毫秒至数百秒。该项目将使用Pb（MG1/3NB2/3）O3-PBTIO3单晶测试XPCS去相关函数的统计分布是否可以区分固有和外在响应的影响。目的是开发一种“两场” XPC方法和一个统计分析工具，以评估固有和外在机制对压电和介电特性的贡献。该项目还旨在通过涉及材料科学，X射线表征和数据科学的多学科研究来教育下一代工程师和科学家。研究结果还将通过各种举措来教育K-12，本科生以及来自代表性不足的少数群体的研究生水平的学生，例如宣传活动和创新的课程工作。这项奖项反映了NSF的法定使命，并认为通过基金会的知识优点和广泛的cribitia cribitia criperia criperia criperia criperia crigitia criperia the Insportauction均值得通过评估。