From Atomic Scale Strain Probing to Smart 3D Interface Design

非技术描述：该项目探索了对异质界面原子尺度应变的基本理解，从而可以设计具有新的或显着改进的材料特性的纳米结构。这项研究对用于存储器、数据存储设备、超导体和固体氧化物燃料电池的先进材料（薄膜形式）产生了直接影响。所获得的基本知识也揭示了在许多其他具有异质界面的陶瓷纳米复合材料系统中观察到的界面现象，如微电子和光电器件，薄膜太阳能电池等。（特别是应变映射结果），包括：（1）进一步发展“苹果的艺术”教学模式，（2）在普渡大学和国家实验室对本科生和研究生进行多学科培训，以及（3）通过高中教师研究计划、校园外展活动和面向所有自学者和材料科学家的研究网站，将研究成果传播给更广泛的受众。技术规格：该项目的重点是外延陶瓷纳米复合材料中异质界面的设计，合成和表征，特别是横向和垂直界面的原子结构和应变分布。该项目的目标是通过探索横向和垂直应变界面的性质来实现基于氧化物的三维（3D）应变异质结构。这些新材料有望具有增强的物理和化学性能，如铁电体、多铁性、超导体和离子导体。具体任务是：（1）对新的层状氧化物系统（例如，Bi 3Fe 2 Mn 2 Ox（BFMO）基系统），（2）探索垂直排列纳米复合材料（货车）中的应变演化（例如，BiFeO 3（BFO）和La0.7Sr0.3MnO3（LSMO）基货车体系），以及（3）通过组合上述横向和垂直纳米结构实现3D界面设计。所有的氧化物薄膜都是通过脉冲激光沉积（PLD）制备的。各种表征技术，如高分辨率X射线衍射（XRD），结合几何相分析-扫描透射电子显微镜（GPA-STEM）的应变映射和电气和离子传输性能测量正在使用。预计基础应变研究可以揭示这些复杂系统的生长机制。此外，新的3D异质氧化物薄膜的开发可以导致具有3D界面设计的新功能，包括增强的铁电性和多铁性，增强的磁阻特性的电子传输路径，以及用于电化学电池的离子导体。

NON-TECHNICAL DESCRIPTION: The project explores the fundamental understanding of atomic-scale strain at heterogeneous interfaces which allows the design of nanostructures with new or significantly improved materials properties. This study is having direct impact on advanced materials (in thin film form) for memories, data storage devices, superconductors, and solid oxide fuel cells. The fundamental knowledge gained is also shedding light on the interfacial phenomena observed in many other ceramic nanocomposite systems with heterogeneous interfaces such as microelectronic and optoelectronic devices, thin film solar cells, etc. The education and outreach activities are integrated with the research (in particular, with the strain mapping results) and include: (1) further development of a teaching model "The Art of Laying Apples", (2) multidisciplinary training of undergraduate and graduate students at Purdue University and national laboratories, and (3) dissemination of research results to a much broader audience through a high school teacher's research program, on-campus outreach activities and a research website for all self-learners and materials scientists. TECHNICAL DETAILS: The project focuses on the design, synthesis, and characterization of heterogeneous interfaces in epitaxial ceramic nanocomposites, in particular on the atomic structure and strain distribution at the lateral and vertical interfaces. The goal of the project is to achieve oxide-based 3-dimensional (3D) strained hetero-structures by exploring the nature of lateral and vertical strained interfaces. These new materials are expected to have enhanced physical and chemical properties as ferroelectrics, multiferroics, superconductors, and ionic conductors. The specific tasks are: (1) conducting an atomic scale quantitative strain mapping/analysis on new layered oxide systems (e.g., Bi3Fe2Mn2Ox (BFMO)-based systems), (2) exploring the strain evolution in vertically aligned nanocomposites (VAN) (e.g., BiFeO3 (BFO) and La0.7Sr0.3MnO3 (LSMO)-based VAN systems), and (3) achieving 3D interface designs by combining the aforementioned lateral and vertical nanostructures. All the oxide thin films are being prepared by pulsed laser deposition (PLD). Various characterization techniques such as high resolution X-ray diffraction (XRD), combined geometric phase analysis-scanning transmission electron microscopy (GPA-STEM) for strain mapping and electrical and ionic transport property measurements are being used. It is anticipated that the fundamental strain study could reveal the growth mechanisms of these complex systems. Moreover, development of new 3D heterogeneous oxide thin films could lead to novel functionalities with 3D interface designs including enhanced ferroelectric and multiferroic properties, electron transport path for enhanced magnetoresistance properties, and ionic conductors for electrochemical cells.